SECTION IX - REPRODUCTIVE SUCESS AND FAILURE
33. Abortion
The definition of abortion is the
termination of pregnancy by any means before the fetus is sufficiently
developed to survive. In the United States this definition is confined to the
termination of pregnancy before 20 weeks based upon the date of the first day
of the last normal menses. Another commonly used definition is the delivery of
a fetus-neonate that weighs less than 500 g.
SPONTANEOUS ABORTION
When abortion occurs without medical or
mechanical means to empty the uterus, it is referred to as spontaneous. Another
widely used term is miscarriage.
PATHOLOGY
Hemorrhage into the decidua basalis and
necrotic changes in the tissues adjacent to the bleeding usually accompany
abortion. The ovum becomes detached, and this stimulates uterine contractions
that result in expulsion. When the sac is opened, fluid is commonly found
surrounding a small macerated fetus, or alternatively there may be no visible
fetus in the sac, the so-called blighted ovum.
Blood or carneous mole is an ovum that is
surrounded by a capsule of clotted blood. The capsule is of varying thickness,
with degenerated chorionic villi scattered through it. The small,
fluid-containing cavity within appears compressed and distorted by thick walls
of old blood clot.
In later abortions,
several outcomes are possible. The retained fetus may undergo maceration. The
bones of the skull collapse and the abdomen becomes distended with
blood-stained fluid. The skin softens and peels off in utero or at the
slightest touch, leaving behind the corium. Internal organs degenerate and
undergo necrosis. Amnionic fluid may be absorbed when the fetus becomes
compressed upon itself and desiccated to form a fetus compressus. Occasionally,
the fetus eventually becomes so dry and compressed that it resembles parchment,
so-called fetus papyraceous.
RESUMPTION OF OVULATION. Ovulation may resume as early as 2 weeks
after an abortion. Lahteenmaki and Luukkainen (1978) detected a surge of
luteinizing hormone (LH) 16 to 22 days after abortion in 15 of 18 women
studied. Moreover, plasma progesterone level, which had plummeted after the
abortion, increased soon after the LH1 surge. These hormonal events are in
temporal agreement with histological changes observed in endometrial biopsies
as described by Boyd and Holmstrom (1972). Therefore, it is important that
effective contraception be initiated soon after abortion.
ETIOLOGY. More than 80 percent of abortions occur in the first 12
weeks, and the rate decreases rapidly thereafter ( Harlap and Shiono, 1980).
Chromosomal anomalies cause at least half of these early abortions, and their
incidence likewise decreases thereafter ( Fig. 33-1). The risk of spontaneous
abortion increases with parity as well as with maternal and paternal age
(Warburton and Fraser, 1964; Wilson and associates, 1986 ). The frequency of
clinically recognized abortion increases from 12 percent in women less than 20
years old to 26 percent in those over age 40. The effect of advancing maternal
age is illustrated in Figure 33-2. For the same paternal ages, the increase is
from 12 to 20 percent. Finally, the incidence of abortion is increased if a
woman conceives within 3 months of a term birth ( Harlap and Shiono, 1980).
The exact
mechanisms responsible for abortion are not always apparent, but in the very
early months of pregnancy, spontaneous expulsion of the ovum is nearly always
preceded by death of the embryo or fetus. For this reason, etiological
considerations of early abortion involve ascertaining whenever possible the
cause of fetal death. In the subsequent months, the fetus frequently does not
die in utero before expulsion, and other explanations for its expulsion must be
invoked.
FETAL FACTORS ABNORMAL ZYGOTE DEVELOPMENT. The most common morphological finding in
early spontaneous abortions is an abnormality of development of the zygote,
embryo, early fetus, or at times the placenta. In an analysis of 1000
spontaneous abortions, Hertig and Sheldon (1943) observed pathological
("blighted") ova in which the embryo was degenerated or absent in
half. Such an abnormal ovum can be seen in Figure 33-3.
Poland and
co-workers (1981) identified morphological disorganization of growth in 40
percent of abortuses that were expelled spontaneously before 20 weeks. Among
embryos of less than 30 mm crown-rump length, the frequency of abnormal
morphological development was 70 percent. Of the embryos on which tissue culture
and chromosomal analyses were performed, 60 percent had chromosomal
abnormalities. For fetuses of 30 to 180 mm crown-rump length, the frequency of chromosomal
abnormalities was 25 percent.
ANEUPLOID ABORTION. Chromosomal abnormalities are common among
embryos and early fetuses that are aborted spontaneously, and account for much
or most of early pregnancy wastage. Approximately 50 to 60 percent of early
spontaneous abortions are associated with a chromosomal anomaly of the
conceptus ( Table 33-1). Jacobs and Hassold (1980) reported that approximately
one fourth of chromosomal abnormalities were due to maternal gametogenesis
errors and 5 percent to paternal errors. In a study of fetuses and newborns
with trisomy 13, Robinson and colleagues (1996) reported that in 21 of 23
cases, the extra chromosome was of
maternal origin.
Autosomal trisomy is the most frequently identified chromosomal
anomaly associated with first-trimester abortions ( Table 33-1). As discussed
in Chapter 36, trisomies can be the result of an isolated nondisjunction, maternal
or paternal balanced translocation, or balanced chromosomal
inversion. Balanced structural chromosomal rearrangements are present in 2
to 3 percent of couples with a history of recurrent abortions ( American
College of Obstetricians and Gynecologists, 1995). Translocations may be
identified in either parent. Balanced chromosomal inversions may also be
identified in couples with recurrent abortions. Trisomies for all autosomes
except chromosome number 1 have been identified in abortuses, but autosomes 13,
16, 18, 21, and 22 are most common.
Monosomy
X (45,X) is the next most
common chromosomal abnormality and is compatible with live-born females (Turner
syndrome). Triploidy is often associated with hydropic placental
degeneration. Incomplete hydatidiform moles may have fetal development that is
triploid or trisomic for chromosome number 16. Fetuses associated with these
frequently abort early, and the few carried longer are all grossly malformed.
Advanced maternal and paternal age are not associated with this abnormality. Tetraploid
abortuses are rarely live born and are most often aborted very early in
gestation.
Chromosomal
structural abnormalities are
unusual causes of abortion and have been identified only since the development
of banding techniques. Some of these infants are live born with balanced
translocations and can be normal. Autosomal monosomy is extremely rare
and is incompatible with life. Sex chromosomal polysomy (47,XXX or 47,XXY) is
unusual in abortus material but is commonly seen in live births.
EUPLOID ABORTION. Kajii and co-workers (1980) reported that
three fourths of aneuploid abortions were before 8 weeks, while euploid
abortions peaked at about 13 weeks. Stein and associates (1980) presented
evidence that the incidence of euploid abortions increases dramatically after
the maternal age of 35 years. The reasons for euploid abortions are generally
unknown, but the following are possibilities:
1.
A
genetic abnormality such as an isolated mutation or polygenic factors.
2.
Various
maternal factors.
3.
Possibly
some paternal factors.
Simpson (1980) observed
that approximately 0.5 percent of live births have chromosomal abnormalities,
while at least 2 percent of live births have diseases associated with a
single-gene mutation or a polygenic mechanism of inheritance.
MATERNAL FACTORS. A variety of medical disorders, environmental
conditions, and developmental abnormalities have been implicated in euploidic
abortion.
INFECTIONS. Some chronic infections have been implicated
in causing abortion. Brucella abortus and Campylobacter fetus are
well-known causes of chronic abortion in cattle, but they are not a significant
cause in humans ( Sauerwein and associates, 1993). Evidence that Toxoplasma
gondii causes abortion in humans is inconclusive. There is no evidence in
humans that either Listeria monocytogenes or Chlamydia trachomatis produce
abortions ( Feist and associates, 1999; Osser and Persson, 1996; Paukku and
associates, 1999). Herpes simplex, however, has been associated with an
increased incidence of abortion following genital infection in early pregnancy.
Temmerman and colleagues (1992) reported that spontaneous abortion was
independently associated with maternal human immunodeficiency virus-1 (HIV-1)
antibody, with maternal syphilis seroreactivity, and with vaginal colonization
with group B streptococci. Serological evidence supportive of a role for Mycoplasma
hominis and Ureaplasma urealyticum in abortion was provided by Quinn
and co-workers (1983). Conversely, Temmerman and associates (1992) found no
association between genital mycoplasma and spontaneous abortion. Interestingly,
Berg and associates (1999) reported that erythromycin treatment for women with
mycoplasma culture-positive amnionic fluid undergoing genetic amniocentesis
resulted in a significant decrease in midtrimester losses (11 versus 44
percent).
CHRONIC DEBILITATING DISEASES. In early pregnancy, chronic wasting diseases
such as tuberculosis or carcinomatosis have seldom caused abortion. Hypertension
is seldom associated with abortion before 20 weeks, but rather may lead to
fetal death and preterm delivery. Celiac sprue has been reported to cause both
male and female infertility and recurrent abortions ( Sher and colleagues,
1994).
ENDOCRINE ABNORMALITIES
HYPOTHYROIDISM There does not appear to be an increased
incidence of abortion associated with clinical hypothyroidism (Montoro and
associates, 1981). Thyroid autoantibodies were associated with an increased
incidence of abortion despite the lack of overt hypothyroidism ( Dayan and Daniels,
1996; Stagnaro-Green and associates, 1990). Conversely, others have found no
increase in the incidence of antithyroid antibodies in women who have recurrent
abortions when compared with normal controls (Esplin and colleagues, 1998;
Pratt and associates, 1994).
DIABETES MELLITUS. As reviewed recently by Greene (1999),
spontaneous abortion and major congenital malformations are both increased in
women with insulin-dependent diabetes. The risk is related to the degree of
metabolic control in the first trimester. In a prospective study, Mills and
associates (1988) reported that early glucose control (within 21 days of
conception) resulted in a similar spontaneous abortion rate compared with
nondiabetic controls. Lack of glucose control, however, resulted in a marked
increase in the abortion rate. In a study from the Children's Hospital of
Pittsburgh, Dorman and associates (1999) reported a significantly higher rate
of spontaneous abortion (27 versus 8 percent) for diabetic women compared with
nondiabetic partners of type I diabetic men. There was a temporal decline in
the spontaneous abortion rate in these diabetic women from 26 percent before
1969 to 5.7 percent from 1980 to 1989. These authors postulated that this
decrease may be secondary to changes in medical care such as glucose
self-monitoring.
PROGESTERONE DEFICIENCY. Insufficient progesterone secretion by the
corpus luteum or placenta has been associated with an increased incidence of
abortion. It has been suggested that abnormal levels of one or more hormones
might help to forecast abortion. Unfortunately, reduced levels of these
hormones are usually the consequence rather than the cause ( Salem and
co-workers, 1984). There are well-documented cases of luteal phase defects, but
they are uncommon.
NUTRITION. There is no conclusive evidence that dietary deficiency
of any one nutrient or moderate deficiency of all nutrients is an important
cause of abortion. The nausea and vomiting that develop rather commonly during
early pregnancy, and any inanition so induced, are rarely followed by
spontaneous abortion.
DRUG USE AND ENVIRONMENTAL FACTORS. A variety of different agents has been
reported, but not confirmed, to be associated with an increased incidence of abortion.
TOBACCO. Smoking has been associated with an increased risk for
euploidic abortion ( Harlap and Shiono, 1980). For women who smoked more than
14 cigarettes a day, the risk was approximately twofold compared with controls
( Kline and associates, 1980). Armstrong and associates (1992) calculated that
the abortion risk increased in a linear fashion by a factor of 1.2 for each 10
cigarettes smoked per day.
ALCOHOL. Both spontaneous abortion and fetal anomalies may result
from frequent alcohol use during the first 8 weeks of pregnancy ( Floyd and
associates, 1999). Spontaneous abortion was increased even when alcohol was
consumed "in moderation." Kline and co-workers (1980) reported that
the abortion rate was doubled in women drinking twice weekly and trebled in
women who consumed alcohol daily compared with nondrinkers. Armstrong and
colleagues (1992) computed that abortion risk increased by an average of 1.3
for each drink per day. In contrast, Cavallo and associates (1995) , in a
prospective study of 546 women, reported that a low level of alcohol
consumption during pregnancy was not associated with a significant risk for
abortion. Somewhat worrisome is the fact that in one cross-sectional study from
the Centers for Disease Control and Prevention, Floyd and associates (1999)
found that half of all pregnant women in the study drank alcohol during the 3
months preceding pregnancy recognition and 5 percent drank moderate to heavy
levels!
CAFFEINE. Coffee consumption at greater than four cups per day
appears to slightly increase the risk of abortion ( Armstrong and associates,
1992). The risk appears to increase with increasing amounts. In a study by
Klebanoff and associates (1999), maternal paraxanthine (a caffeine metabolite)
levels were associated with a significant twofold risk of spontaneous abortion
only if extremely high. These authors concluded that moderate consumption of
caffeine was unlikely to be associated with spontaneous abortion.
RADIATION. In sufficient doses, radiation is a recognized
abortifacient. As discussed in Chapter 42, the human dose is not precisely
known.
CONTRACEPTIVES. There is no evidence to support that oral
contraceptives or spermicidal agents used in contraceptive creams and jellies
are associated with an increased incidence of abortion. Intrauterine devices,
however, are associated with an increased incidence of septic abortion after
contraceptive failure ( Chap. 58, p. 1538).
ENVIRONMENTAL TOXINS. In some studies abortion rates in exposed
women were not increased ( Axelsson and Rylander, 1982). Rowland and associates
(1995) reported an increased risk for spontaneous abortion among dental
assistants exposed to 3 or more hours of nitrous oxide in offices without
scavenging equipment, but not in offices using such equipment. In a
meta-analysis, Boivin (1997) concluded that there was an increased risk of
spontaneous abortion for women occupationally exposed to anesthetic gases based
on data from the prescavenging era.
In most instances,
there is little information to indict any specific environmental agent;
however, there is evidence that arsenic, lead, formaldehyde, benzene, and ethylene
oxide may cause abortion (Barlow and Sullivan, 1982). Video display terminals
and exposure to the accompanying electromagnetic fields do not increase the risk
of abortion (Schnorr and co-workers, 1991). Short-waves and ultrasound also do
not increase the risk ( Taskinen and colleagues, 1990 ).
IMMUNOLOGICAL FACTORS. Much attention has focused on the immune
system as important in recurrent pregnancy loss. Two primary pathophysiological
models that have evolved are the autoimmune theory (immunity against self) and
the alloimmune theory (immunity against another person).
AUTOIMMUNE FACTORS. It has been determined from compiled studies
that approximately 15 percent of over 1000 recurrent pregnancy loss patients
have recognized autoimmune factors (Kutteh and Pasquarette, 1995). The most
significant antibodies have specificity against negatively charged
phospholipids and are most commonly detected by testing for lupus anticoagulant
(LAC) and anticardiolipin antibody (ACA). Women with both a history of early
fetal loss and high levels of antibodies may suffer a 70 percent miscarriage
recurrence ( Dudley and Branch, 1991). Pooling studies totaling 1500 women with
recurrent loss yields an average incidence of 17 percent for anticardiolipin
antibody and 7 percent for the lupus anticoagulant. In contrast, only 1 to 3
percent of normal obstetrical patients are found to have either of these
(Harris and Spinnato, 1991; Lockwood and colleagues, 1989). In a prospective
study of 860 women screened for anticardiolipin antibody in the first
trimester, Yasuda and colleagues (1995) reported that 7 percent were positive.
Spontaneous abortion occurred in 25 percent of the antibody-positive group compared
with 10 percent of the negative group. In another recent study, however,
Simpson and associates (1998) found no association between early pregnancy loss
and the presence of either anticardiolipin antibody or lupus anticoagulant.
Despite these controversies with early abortion, there is a consensus regarding
increased midtrimester pregnancy losses and the antiphospholipid antibody
syndrome ( Blumenfeld and Brenner, 1999; Cowchock, 1997; Simpson and
associates, 1998).
The lupus
anticoagulant is an immunoglobulin (IgG, IgM, or both) that interferes with one
or more of the phospholipid-dependent tests of in vitro coagulation. The term is
a misnomer because it is associated with clinically important increases in
thromboembolic events. Importantly, the lupus anticoagulant is most often
diagnosed in patients who do not meet the diagnostic criteria for lupus.
Antiphospholipid
antibodies are acquired antibodies targeted against a phospholipid. They can be
of the IgG, IgA, or IgM isotope. The mechanism of pregnancy loss in these women
is thought to involve placental thrombosis and infarction. One mechanism may
involve the inhibition of prostacyclin release ( Fig. 33-4). This product of
endothelial cells is a potent vasodilator and inhibitor of platelet
aggregation. On the other hand, platelets produce thromboxane A 2, a
vasoconstrictor and platelet aggregator. These antibodies therefore may reduce
prostacyclin production, facilitating a thromboxane dominant milieu that leads
to thrombosis. In addition, they have been shown to inhibit protein C
activation.
Investigators have
proposed various treatments for the antiphospholipid antibody syndrome,
including low-dose aspirin, prednisone, heparin, and intravenous immunoglobulin
(Coulam, 1995). These treatments are thought to counteract the adverse action
of antibodies by affecting both the immune and coagulation systems. Cowchock
and colleagues (1992) performed a randomized trial comparing prednisone to
low-dose heparin therapy in 20 women with antibodies and recurrent pregnancy
loss. Live-birth rates were equal (75 percent) for both groups. However, those
women receiving a glucocorticoid demonstrated a significantly greater incidence
of maternal and fetal morbidity. Kutteh (1996) described 50 such women who were
treated with either heparin and low-dose aspirin or aspirin alone. Heparin was
initiated at 5000 units subcutaneously twice daily with a positive pregnancy
test and titrated according to the partial thromboplastin time and platelet count.
Although 76 percent of women in the heparin plus aspirin group delivered viable
infants, only 44 percent of those treated with aspirin alone had a live birth. Maternal
and obstetrical complications were low in both groups. Recent data indicate
that antibodies bind directly to heparin in vitro and function in a similar way
in vivo, thereby decreasing the adverse effects of the antibodies ( Ermel and
associates, 1995).
Branch and
associates (2000) conducted a placebo-controlled pilot study of immune globulin
for the treatment of the antiphospholipid antibody syndrome during pregnancy
and found that intravenous immune globulin did not improve pregnancy outcomes
above that achieved with heparin and low-dose aspirin.
ALLOIMMUNE FACTORS. A number of women with recurrent pregnancy
loss have been diagnosed as having an alloimmune cause. They have received a
variety of therapies targeted at stimulating maternal immune tolerance of fetal
material. Diagnosis of an alloimmune factor has centered on several tests:
1.
Maternal
and paternal HLA comparison.
2.
Assessment
of maternal serum for the presence of cytotoxic antibodies to paternal
leukocytes.
3.
Maternal
serum testing for blocking factors for maternal-paternal mixed lymphocyte
reactions.
In essence, those couples determined to have
significant HLA-type homology, or in which the women were found to have minimal
antipaternal antibodies, were judged to represent an alloimmune disorder.
The validity of
this model remains doubtful. For example, human HLA sharing clearly does not
preclude successful pregnancies ( Ober and co-workers, 1983). Most importantly,
other studies have compared HLA sharing frequency in couples with recurrent
losses with those with reproductive success and observed no differences (Bellingard,
1995; Houwert-de Jong, 1989; Sargent, 1988; and their associates). Although
some investigators have found the presence of lymphocytotoxic antibodies and
mixed lymphocyte culture inhibitors to be associated with women with successful
pregnancies, Coulam (1992) has conclusively shown these to be a function of the
duration and number of pregnancies rather than a reason for pregnancy loss.
Furthermore, the results of these three tests were found to have no predictive
value in assessing risks for subsequent pregnancy outcome in a population of
women with recurrent losses ( Cowchock and Smith, 1992).
Notwithstanding the
uncertainties surrounding the most prevalent hypotheses of alloimmune causes of
recurrent pregnancy loss, a number of studies have described outcomes following
therapy to improve the maternal immune milieu. The majority of these women
received either paternal leukocytes or pooled human immunoglobulin. Fraser and
associates (1993) performed meta-analysis of 19 case series and concluded that
immunotherapy does not significantly improve pregnancy outcome. A retrospective
worldwide observational study and meta-analysis on allogenic leukocyte
immunization therapy for recurrent pregnancy loss in over 400 cases
demonstrated marginal improvement for immunized women (Coulam and colleagues,
1994 ). The considerable expense and potential morbidity associated with
immunization therapy make full disclosure of relevant information and informed
consent important ( Bux and co-workers, 1992; Katz and associates, 1992).
Some physicians
have infused pooled human immunoglobulin as an alternative to paternal lymphocyte
therapy. A prospective, double-blind, placebo-controlled trial using
intravenous gamma globulin to treat women with recurrent loss demonstrated an
improvement in women receiving this treatment versus placebo ( Coulam, 1995).
In another prospective study of 47 women with a history of three or more
unexplained pregnancy losses, Stricker and associates (2000) reported that
low-dose intravenous immunoglobulin (IVIG) was beneficial in improving
pregnancy outcome. Of the 24 women receiving IVIG therapy who subsequently
became pregnant, 22 had a term pregnancy. There were 11 women who refused IVIG
therapy and seven subsequently became pregnant but all had first-trimester
spontaneous abortions.
INHERITED THROMBOPHILIA. There have been numerous reports of an association
of spontaneous abortions and inherited thrombophilias ( Blumenfeld, 1999; Girling,
1998; Nelen, 1997; Ridker; 1998; Souza, 1999; Younis, 2000 and all their
associates). As discussed in Chapter 49 (p. 1330), other pregnancy
complications have also been associated with these thrombophilias ( Table
33-2). In a study of 78 consecutive women with two or more first- or
second-trimester losses, Younis and associates (2000) reported that 38 percent
versus 8 percent of controls had activated protein C resistance and 19 percent
versus 6 percent of controls had factor V Leiden mutation. Nelen and colleagues
(2000) reported that elevated serum homocysteine levels were also a risk
factor. Blumenfeld and Brenner (1999) recently reviewed thrombophilia-associated
pregnancy wastage.
The optimal
treatment for the various thrombophilias during pregnancy is unclear, but
heparin (including low molecular weight heparin) appears to be efficacious for the
treatment of antithrombin III deficiency as well as protein C and S deficiency.
Aspirin plus heparin seems to be efficacious for treatment of factor V Leiden
mutation and antiphospholipid syndrome ( Blumenfeld and Brenner, 1999).
AGING GAMETES.Guerrero and Rojas
(1975) found an increased incidence of abortion relative to successful
pregnancies when insemination occurred 4 days before or 3 days after the time
of shift in basal body temperature. They concluded, therefore, that aging of
the gametes within the female genital tract before fertilization increased the
chance of abortion. Dickey and colleagues
(1992) reported that infertility patients over 35 had a higher incidence
of small amnionic sac syndrome and an increased incidence of
euploidic abortion. Whether ovulation induction or in vitro fertilization
result in aging of gametes prior to implantation is not known.
LAPAROTOMY. There is no evidence
that surgery performed during early pregnancy causes increased abortions ( Chap. 42, p. 1144). For
example, ovarian tumors
and pedunculated myomas are generally removed without interfering
with pregnancy. Peritonitis increases the likelihood of abortion.
PHYSICAL TRAUMA. Trauma that
failed to interrupt the pregnancy is often forgotten. Only the particular event
apparently related temporally to abortion is
remembered. Most spontaneous abortions, however, occur some time
after death of the embryo or fetus.
UTERINE DEFECTS ACQUIRED
UTERINE DEFECTS. Even large and multiple
uterine leiomyomas usually do not cause abortion. When associated with abortion,
their location is apparently more important than their size ( Chap. 35, p. 927). Uterine synechiae
(Asherman syndrome) are caused by destruction of large areas of
endometrium by curettage. This in turn results in amenorrhea and
recurrent abortions believed to be due to insufficient endometrium to support
implantation. The
diagnosis can be made by a hysterosalpingogram that shows
characteristic multiple filling defects, but the most accurate and direct
diagnosis is made by
hysteroscopy (Raziel and colleagues,
1994). Romer (1994) reported that the incidence of intrauterine adhesions diagnosed by
hysteroscopy was about the same after
the first incomplete or missed abortion (20 percent), but was
significantly higher in women with recurrent abortions (approximately 50
percent). Recommended
treatment is lysis of the adhesions via hysteroscopy and placement
of an intrauterine contraceptive device to prevent recurrence. Continous
high-dose estrogen
therapy is also recommended by some practitioners for 60 to 90
days. March and Israel (1981) reported
that abortions decreased from 80 to 15 percent with such
therapy.
DEVELOPMENTAL UTERINE DEFECTS. These
defects are the consequence of abnormal mullerian duct formation or fusion; or
they may occur spontaneously or be
induced by in utero exposure to diethylstilbestrol ( Chap. 35). Some types, such as
uterine septa, may be associated with abortions. Porcu
and associates (2000)
described pregnancy outcomes in 63 women with a septate uterus.
They all underwent hysteroscopic resection of the septa because of repeat
pregnancy loss or
abnormal fetal presentation. There were 26 term live births
following this procedure. In a recent review, Homer
and associates (2000) reported that hysteroscopic
septoplasty resulted in improved pregnancy outcome in women with
repeated pregnancy loss.
INCOMPETENT CERVIX. The term incompetent
cervix is applied to a discrete obstetrical entity. It is characterized by
painless cervical dilatation in the second
trimester or perhaps early in the third trimester, with prolapse
and ballooning of membranes into the vagina, followed by rupture of membranes
and expulsion of an
immature fetus. Unless effectively treated, this sequence tends to
repeat in each pregnancy.
Numerous methods have been described in nonpregnant women to make
the diagnosis, usually by documenting a more widely dilated internal cervical
os than is
normal. Methods have included hysterography, pull-through
techniques of inflated catheter balloons, and acceptance without resistance at
the internal os of
specifically sized cervical dilators ( Ansari and Reynolds, 1987). During
pregnancy, attempts have been made with moderate success to predict premature
cervical
dilation using ultrasonic techniques ( Michaels and associates, 1989). Iams and co-workers (1995) performed a
cross-sectional study of cervical length measured by
transvaginal ultrasonography in women with a prior preterm
delivery, those with cervical incompetence, and normal controls delivered at
term. Gestational age at the
first preterm delivery was significantly correlated with cervical
length in the pregnancy evaluated at each gestational age between 20 and 30
weeks. Andrews and
associates (2000), in a
study of 53 women with ultrasound evaluation prior to 20 weeks, reported an
association of short cervical lengths or funneling of the internal
cervical os and early spontaneous preterm births. Several authors
have reported on the use of transfundal pressure during transvaginal ultrasound
evaluation of the
cervix as an aid in the detection of asymptomatic incompetent
cervix ( Guzman and colleagues, 1997a, 1997b, 1998; Rocco and Garrone, 1999).
Kurup and Goldkrand (1999), in a
study comparing elective, emergent, or urgent cerclage, concluded that
ultrasound was useful in identifying women with subtle
changes in the cervix who would benefit from urgent cerclage.
Ultrasound has also been utilized to demonstrate an increase in cervical length
after prophylactic or
therapeutic cerclage (Althuisius
and co-workers, 1999; Funai and colleagues, 1999 ). The use
of magnetic resonance imaging in the diagnosis of incompetent cervix
was recently reported by Maldjian
and associates (1999).
There is little doubt that ultrasound, especially transvaginal, is
a useful adjunct for the diagnosis of cervical shortening or funneling of the
internal os and in the early
detection of cervical incompetence. The diagnosis, however,
remains difficult in most women and is still often based on clinical examination
and history.
ETIOLOGY. Although the cause of
cervical incompetence is obscure, previous trauma to the cervix—especially in
the course of dilatation and curettage, conization,
cauterization, or amputation—appears to be a factor in many cases.
In other instances, abnormal cervical development, including that following
exposure to
diethylstilbestrol in utero, plays a role ( Chap. 35, p. 918).
TREATMENT. The treatment of
cervical incompetence is surgical, consisting of reinforcement of the weak
cervix by some type of purse-string suture. Bleeding,
uterine contractions, or ruptured membranes are usually
contraindications to surgery.
PREOPERATIVE EVALUATION. Cerclage
should generally be delayed until after 14 weeks so that early abortions due to
other factors will be completed. There is no
consensus as to how late in pregnancy the procedure should be
performed. The more advanced the pregnancy, the more likely surgical
intervention will stimulate
preterm labor or membrane rupture. For these reasons, some clinicians
prefer bed rest rather than cerclage some time after midpregnancy. We usually
do not perform
cerclage after 24 to 26 weeks.
Aarts and associates (1995) provided a
review of late second-trimester cerclage, commonly known as an emergency
cerclage. They concluded that emergency
cerclage can be of benefit in some women, but that the incidence
of complications, especially infection, is high. According to Schorr and Morales (1996) , bulging
membranes are associated with significantly increased failure rates.
Caruso and associates (2000) reported
their experience with emergency cerclage in 23 women
with a dilated cervix and protruding membranes (gestational age 17
to 27 weeks). There were 11 live-born infants and they concluded that the
success of the
procedure was unpredictable. In a 10-year review of 75 emergency
cerclages, Chasen and Silverman (1998) reported that 65 percent of the women delivered at 28
weeks or later, and half delivered at 37 weeks or greater. Only 44
percent of those with bulging membranes at the time of cerclage reached 28
weeks. Amnioreduction
at the time of emergency cerclage may improve pregnancy
prolongation (Locatelli and associates, 1999 ).
Sonography to confirm a living fetus and to exclude major fetal
anomalies is done prior to cerclage. Obvious cervical infection should be
treated, and cultures for
gonorrhea, chlamydia, and group B streptococci are recommended.
For at least a week before and after surgery, there should be no sexual
intercourse.
If there is a question as to whether cerclage should be performed,
the woman is placed at decreased physical activity. Proscription of intercourse
is essential, and
frequent cervical examinations should be conducted to assess
cervical effacement and dilatation. Weekly ultrasonic surveillance of the lower
uterine segment
between 14 and 27 weeks may prove useful in some women (Guzman and associates, 1998; Michaels and colleagues, 1989).
Unfortunately, rapid effacement and
dilatation develop even with such precautions ( Witter, 1984).
CERCLAGE PROCEDURES. Three types
of operations are commonly used during pregnancy. One is a simple procedure
recommended by McDonald (1963) and
illustrated in Figure 33-5. The second is the more complicated Shirodkar operation (1955). The third
is the modified Shirodkar procedure shown in Figure
33-6. There
is less trauma and blood loss with both the McDonald and modified
Shirodkar procedures than with the original Shirodkar procedure.
In many cases, filling the bladder with 600 mL of saline through
an indwelling Foley catheter will serve to push the fetus and membranes upward
from the ballooning
lower segment. Some clinicians recommended placement of a 30-mL
balloon Foley catheter through the cervix and inflating the balloon with saline
to deflect the
amnionic sac cephalad.
Success rates approaching 85 to 90 percent are achieved with both
McDonald and modified Shirodkar techniques ( Caspi
and associates, 1990; Kuhn and Pepperell,
1977). Thus, there appears to be
little reason for performing the more complicated original Shirodkar procedure.
The modified Shirodkar procedure is often reserved
for previous McDonald cerclage failures and structural cervical
abnormalities. Success rates are higher when cervical dilatation was minimal
and membrane prolapse
was absent.
Transabdominal cerclage placed at the level of the uterine isthmus
has been recommended in some instances, especially in cases of anatomical
defects of the cervix
or failed transvaginal cerclage ( Cammarano
and colleagues, 1995; Gibb and Salaria, 1995; Herron and Parer, 1988). The
procedure requires laparotomy for
placement of the suture and another laparotomy for its removal,
for delivery of the fetus, or both. The potential for trauma and other
complications initially and
subsequently is much greater with this procedure than with the
vaginal procedures. Turnquest and colleagues
(1999) recently described fetal salvage in 9 of 11
women with abdominal cerclage.
COMPLICATIONS. Charles
and Edward (1981) identified complications,
especially infection, to be much less frequent when cerclage was performed by
18 weeks.
When performed much after 20 weeks, there was a high incidence of
membrane rupture, chorioamnionitis, and intrauterine infection. With clinical
infection, the suture
should be cut, and labor induced.
There is no evidence that prophylactic antibiotics prevent
infection, or that progestational agents or ß-mimetic drugs are of any
adjunctive value ( Thomason and
co-workers, 1982). In the event that
the operation fails and signs of imminent abortion or delivery develop, it is
urgent that the suture be released at once; failure to do
so may result in grave sequelae. Rupture of the uterus or cervix
may be the consequence of vigorous uterine contractions with the ligature in
place. Membrane
rupture during suture placement or within the first 48 hours of
surgery is considered by some to be an indication to remove the cerclage. Kuhn and Pepperell (1977)
reported that when the membranes rupture in the absence of labor,
the likelihood of serious fetal or maternal infection is increased appreciably
if the suture is left in
situ and delivery is delayed. Still, the range of management
options spans from observation, to removal of the cerclage with observation, to
removal of the cerclage
and labor induction (Barth,
1995). There are insufficient data upon which to base any firm
recommendation, and the optimal management of such patients remains
controversial (O'Connor and
associates, 1999).
Following the Shirodkar operation, the suture can be left in place
if it remains covered by mucosa, and cesarean delivery performed near term.
Conversely, the
Shirodkar suture may be removed and vaginal delivery permitted.
PATERNAL FACTORS. Little is
known about paternal factors in the genesis of spontaneous abortion. Certainly,
chromosomal translocations in sperm can lead to
abortion. Kulcsar and associates
(1991) found adenovirus or herpes simplex virus in nearly 40 percent of
semen samples obtained from sterile men. The viruses were
detected in latent form in 60 percent of the cells, and the same
viruses were found in abortuses.
CATEGORIES AND TREATMENT OF SPONTANEOUS ABORTION
It is convenient to consider the clinical aspects of spontaneous
abortion under five subgroups: threatened, inevitable, incomplete, missed, and
recurrent abortion.
THREATENED ABORTION. The
clinical diagnosis of threatened abortion is presumed when any bloody vaginal
discharge or bleeding appears during the first half of
pregnancy. It is an extremely commonplace occurrence, and one out
of four or five women has vaginal spotting or heavier bleeding during early
gestation. Of those
women who bleed in early pregnancy, approximately half will abort.
The bleeding of threatened abortion frequently is slight, but it may persist
for days or weeks.
Unfortunately, an increased risk of suboptimal pregnancy outcome
in the form of preterm delivery, low birthweight, and perinatal death persists
( Batzofin and
associates, 1984; Funderburk and colleagues, 1980).
Importantly, the risk of a malformed infant does not appear to be increased.
Some bleeding about the time of expected menses may be
physiological. Cervical lesions are likely to bleed in early pregnancy,
especially after intercourse. Polyps
presenting at the external cervical os as well as decidual
reaction in the cervix tend to bleed in early gestation. A significant clinical
point is that lower abdominal pain
and persistent low backache do not accompany bleeding from these
benign causes.
Because most physicians consider any bleeding in early pregnancy
to be a sign of threatened abortion, any treatment of so-called threatened
abortion has a
considerable likelihood of success. Most women who actually are
threatening to abort will ultimately do so no matter what is done. If, however,
bleeding is attributable
to one of the unrelated causes mentioned previously, it is likely
to disappear, regardless of treatment.
If an intrauterine device is still present and the
"string" is visible, the device should be removed for reasons cited
in Chapter 58 (p. 1539).
Bleeding usually begins first, and cramping abdominal pain follows
a few hours to several days later. The pain of abortion may be anterior and
clearly rhythmic; it may
be a persistent low backache, associated with a feeling of pelvic
pressure; or it may be a dull, midline, suprapublic discomfort. Whichever form
the pain takes,
prognosis for pregnancy continuation in the presence of bleeding
and pain is poor. Higher perinatal mortality rates are observed in women whose
pregnancies were
complicated early by threatened abortion.
Each woman should be examined for there is always the possibility
that the cervix already is dilated and abortion is inevitable, or there is a
serious complication such
as extrauterine pregnancy or torsion of an unsuspected ovarian
cyst. She may be kept at home in bed with analgesia given to help relieve the
pain. If the bleeding
persists, she should be reexamined and the hematocrit rechecked.
If blood loss is sufficient to cause anemia or hypovolemia, evacuation of the
pregnancy is generally
indicated.
Women with threatened abortion have been treated with progesterone
intramuscularly or with a wide variety of synthetic progestational agents
orally or
intramuscularly. Unfortunately, there evidence of effectiveness is
lacking. "Success" from the use of these agents often results in no
more than a missed abortion.
Occasionally, slight bleeding may persist for weeks. It then
becomes essential to decide whether there is any possibility of continuation of
the pregnancy. Vaginal
sonography, serial serum quantitative chorionic gonadotropin (hCG)
levels, and serum progesterone values, measured alone or in various
combinations, have proven
helpful in ascertaining if a live intrauterine pregnancy is
present. Fossum and associates (1988) reported that a fetal sac can usually be seen using vaginal
sonography between 33 and 35 days from the last menstrual period (
Table 33-3). This was associated with
a chorionic gonadotropin level of about 1000 mIU/mL.
Thus, if a gestational sac can be seen and serum hCG2 is less than 1000 mIU/mL,
the gestation is not likely to survive. If any doubt exists, however, serial
gonadotropin levels should be measured.
Al-Sebai and associates (1995) reported
that a single progesterone measurement had an 88 percent sensitivity and specificity
in predicting a live versus dead
intrauterine fetus or a tubal pregnancy. Stovall and associates (1992) reported
that only about 1 percent of abnormal pregnancies (spontaneous incomplete
abortions
and ectopic pregnancies) have a serum progesterone level of 25
ng/mL or greater. A serum progesterone value of less than 5 ng/mL was
associated with a dead
conceptus, but this did not localize the pregnancy as uterine or
extrauterine. Hahlin and colleagues (1990) reported that no live intrauterine pregnancy had a
progesterone level less than 10 ng/mL; and 88 percent of ectopic
pregnancies and 83 percent of spontaneous abortions had lower values.
Therefore, with a fetal sac
clearly visible, a gonadotropin level of less than 1000 mIU/mL,
and a serum progesterone value of less than 5 ng/mL, there almost certainly is
not an intrauterine
pregnancy.
Sonographic demonstration of a distinct, well-formed gestational
ring with central echoes from the embryo implies that the products of
conception are reasonably
healthy (Table 33-3). A gestational sac with no central echoes from an embryo or
fetus implies strongly, but does not prove, death of the conceptus. When
abortion is
inevitable, mean gestational sac diameter is frequently smaller
than appropriate for gestational age. All viable intrauterine pregnancies are
visible by transvaginal
ultrasonography by 41 days' gestation ( Lipscomb and colleagues, 2000).
Moreover, by approximately 45 days after the last menses and thereafter, fetal
heart action
should be discernible using real-time ultrasound. Emerson and associates (1992) and Pellerito and colleagues (1992) reported
excellent results in identifying live
intrauterine gestations using vaginal color and pulsed Doppler
flow imaging techniques.
After death of the conceptus, the uterus should be emptied. All
tissue passed should be examined to determine whether the abortion is complete.
Unless all of the
fetus and placenta can be positively identified, curettage may be
required. Vaginal probe or abdominal ultrasound may assist in this
decision-making process. If
significant amounts of material are retained within the uterine
cavity, curettage is recommended by most clinicians. Ectopic pregnancy should
always be considered in
the differential diagnosis of threatened abortion. This is
especially so if the gestational sac or fetus are not identified. Frozen
section of the curettings may further
assist with diagnosis.
Women who are D negative with a threatened abortion probably
should receive anti-D immunoglobulin ( Chap. 39,
p. 1067). Von Stein and associates
(1992) reported
that more than 10 percent of such women had significant
fetomaternal hemorrhage.
INEVITABLE ABORTION. Inevitability
of abortion is signaled by gross rupture of the membranes in the presence of
cervical dilatation. Under these conditions,
abortion is almost certain. Rarely, a gush of fluid from the
uterus during the first half of pregnancy is without serious consequence. The
fluid may have collected
previously between the amnion and chorion. Most often, however,
either uterine contractions begin promptly, resulting in expulsion of the
pregnancy, or infection
develops.
With obvious membrane rupture during the first half of pregnancy,
the possibility of salvaging the pregnancy is very unlikely. If in early pregnancy
the sudden
discharge of fluid, suggesting ruptured membranes, occurs before
any pain or bleeding, the woman may be put to bed and observed for further
leakage of fluid,
bleeding, cramping, or fever. If after 48 hours there has been no
further escape of amnionic fluid, no bleeding or pain, and no fever, she may
get up and, except for
any form of vaginal penetration, continue her usual activities.
If, however, the gush of fluid is accompanied or followed by bleeding and pain,
or if fever ensues,
abortion should be considered inevitable and the uterus emptied.
INCOMPLETE ABORTION. The fetus
and placenta are likely to be expelled together in abortions occurring before
10 weeks, but separately thereafter. When the
placenta, in whole or in part, is retained in the uterus, bleeding
ensues sooner or later, to produce the main sign of incomplete abortion. With
abortions that are more
advanced, bleeding occasionally may be massive to the point of
producing profound hypovolemia.
In instances of incomplete abortion, it is often unnecessary to
dilate the cervix before curettage. In many cases, the retained placental
tissue simply lies loose in the
cervical canal and can be lifted from an exposed external os with
ovum or ring forceps. Suction curettage, as described later, is effective for
evacuating the uterus. A
woman with a more advanced pregnancy, or a woman who is bleeding
heavily, should be hospitalized and the retained tissue removed without delay.
Hemorrhage
from incomplete abortion is occasionally severe but rarely fatal.
Fever is not a contraindication to curettage once appropriate antibiotic
treatment has been started (p.
877).
Nielsen and Hahlin (1995) performed a
randomized study comparing expectant management with curettage for spontaneous
abortions less than 13 weeks.
Spontaneous resolution of pregnancy occurred within 3 days in 80
percent of women treated conservatively, although vaginal bleeding lasted on
the average one day
longer. Complications were similar between the groups.
MISSED ABORTION. This is
defined as retention of dead products of conception in utero for several weeks.
The rationale for an exact time period is not clear, and it
serves no useful clinical purpose. In the typical instance, early
pregnancy appears to be normal, with amenorrhea, nausea and vomiting, breast
changes, and growth
of the uterus. After fetal death, there may or may not be vaginal
bleeding or other symptoms denoting a threatened abortion. For a time, the
uterus seems to remain
stationary in size, but mammary changes usually regress. The woman
is likely to lose a few pounds. Thereafter, it becomes apparent that the uterus
not only has
ceased to enlarge but also has become smaller. Many women have no
symptoms during this period except persistent amenorrhea. If the missed abortion
terminates
spontaneously, and most do, the process of expulsion is the same
as in any abortion. If retained several weeks after death, it becomes a
shriveled sac containing a
macerated fetus (Fig. 33-7). Egarter and associates
(1995) reported that gemeprost vaginal suppositories (prostaglandin E 1)
were effective in the termination of
first-trimester missed abortions in 77 percent of women.
Occasionally, after prolonged retention of the dead fetus, serious
coagulation defects develop. This is more likely when the gestation reached the
second trimester
before fetal death. The woman may note troublesome bleeding from
the nose or gums and especially from sites of slight trauma. The pathogenesis
and treatment of
coagulation defects and any attendant hemorrhage in instances of
prolonged retention of a dead fetus are considered in Chapter 25 (p. 659).
The reason some abortions do not terminate after fetal death is
not clear. The use of potent progestational compounds to treat threatened
abortion, however, may
contribute to this. Smith and
co-workers (1978) observed that 73 percent of
women with threatened abortion given hormonal treatment did abort, but on the
average
20 days later. In women who received no hormonal support, 67
percent aborted at a mean of 5 days.
RECURRENT ABORTION. This has
been defined by various criteria of number and sequence, but probably the most
generally accepted definition refers to three or
more consecutive spontaneous abortions. Repeated spontaneous
abortions are likely to be chance phenomena in the majority of cases. Accepting
an independent
risk of miscarriage occurrence to be 15 percent, a second loss
could be calculated to occur at a rate of 2.3 percent and a third loss in 0.34
percent of women. In a
study of women doctors, the occurrences of one, two, and three
miscarriages were reported to be 10.4, 2.3, and 0.34 percent, respectively ( Alberman, 1988).
Approximately 1 to 2 percent of women of reproductive age will
experience three or more spontaneous, consecutive abortions, and as many as 5
percent will have two
or more recurrent abortions (Blumenfeld
and Brenner, 1999).
Epidemiologically, there is some uniformity in the proportion of
recurrent pregnancy loss with chromosomal anomalies. Despite this, however,
there are significant
discrepancies when compared with the relative prevalence of other
categories. There are several reasons to explain this: First, differences in
definition make direct
comparisons between various studies questionable. For example,
some authors included women with only two losses into their analysis. Second,
methods used to
assign women to various diagnostic categories differ. Complicating
this issue is that many diagnoses under consideration are debatable, both as to
the criteria used
and to their actual contribution to pregnancy loss. Third, the
intensity of evaluation applied prior to categorizing a woman as
"unexplained" varied among these
studies. In general, the majority of studies have observed that
women with three or more miscarriages more commonly are determined to have a
chromosomal
anomaly, endocrinological disorder, or an altered immune system ( Table 33-4).
PROGNOSIS. With the exception of
antiphospholipid antibodies and an incompetent cervix, the apparent "cure
rate" after as many as three consecutive spontaneous
abortions will range between 70 and 85 percent regardless of
treatment. That is, the loss rate will be higher, but not a great deal higher,
than that anticipated for
pregnancies in general. In fact, Warburton
and Fraser (1964) reported that the likelihood
of recurrent abortion was 25 to 30 percent regardless of the number of
previous abortions. Poland
and associates (1977) noted that if a woman had
previously delivered a live-born infant, the risk for each recurrent abortion
was
approximately 30 percent. If, however, the woman had no live-born
infants and had experienced at least one spontaneous fetal loss, the risk of
abortion was 46
percent. Women with three or more spontaneous abortions are at
increased risk in a subsequent pregnancy for preterm delivery, placenta previa,
breech
presentation, and fetal malformation (Thom and colleagues, 1992).
INDUCED ABORTION
Induced abortion is the medical or surgical termination of
pregnancy before the time of fetal viability. In 1996, a total of 1,221,585
legal abortions were reported to the
Centers for Disease Control and Prevention (1999) . Approximately 20 percent of these women were 19 years of age or
less and the majority were less than 25 years
of age, white, and unmarried (Centers
for Disease Control and Prevention, 2000 ). About 88
percent of abortions were performed before 13 weeks, 55 percent before 8
weeks, and 16 percent at 6 weeks or less.
LEGAL ASPECTS. Until the
United States Supreme Court decision of 1973, only therapeutic abortions could be performed legally in most
states. The most common
legal definition of therapeutic abortion until then was
termination of pregnancy before the period of fetal viability for the purpose
of saving the life of the mother. A few
states extended their laws to read "to prevent serious or
permanent bodily injury to the mother" or "to preserve the life or
health of the woman." Some states allowed
abortion if pregnancy was likely to result in the birth of an
infant with grave malformations.
The stringent abortion laws in effect until 1973 were of fairly
recent origin. Abortion before quickening—the first definite perception of
fetal movement, which most
often occurs between 16 and 20 weeks' gestation—was either lawful
or widely tolerated in both the United States and Great Britain until 1803. In
that year, as part of a
general restructuring of British criminal law, a statute was
enacted that made abortion before quickening illegal. The Roman Catholic
Church's traditional
condemnation of abortion did not receive the ultimate sanction of
universal law (excommunication) until 1869 ( Pilpel
and Norwich, 1969).
It was not until 1821 that Connecticut enacted the nation's first
abortion law. Subsequently, throughout the United States, abortion became
illegal except to save the
life of the mother. Because therapeutic abortion to save the life
of the woman is rarely necessary or definable, it follows that the great
majority of such operations
previously performed in this country went beyond the letter of the
law. Borgmann and Jones (2000) have
extensively reviewed legal issues in providing abortions.
INDICATIONS. Some
indications for therapeutic abortion are discussed with the diseases that
commonly lead to the operation. Well-documented indications are
persistent heart disease after previous cardiac decompensation and
advanced hypertensive vascular disease. Another is invasive carcinoma of the
cervix. The
American College of Obstetricians and Gynecologists (1987) established guidelines for therapeutic abortion:
• When continuation of pregnancy may threaten the life of the
woman or seriously impair her health. In determining whether or not there is
such a risk to health,
account may be taken of her total environment, actual or
reasonably foreseeable.
• When pregnancy has resulted from rape or incest. In this case,
the same medical criteria should be employed in evaluation of the woman.
• When continuation of pregnancy is likely to result in the birth
of a child with severe physical deformities or mental retardation. Issues such
as maternal HIV-13
infection are less clear-cut but problematic ( Araneta and colleagues, 1992).
ELECTIVE (VOLUNTARY) ABORTION
Elective or voluntary abortion is the interruption of pregnancy
before viability at the request of the woman but not for reasons of impaired
maternal health or fetal
disease. Most abortions done today fall into this category; in
fact, there is approximately one elective abortion for every three live births
in the United States.
LEGALITY. It was only about 25
years ago when elective abortion was again legalized in the United States.
Several Supreme Court decisions are noteworthy in the
history of abortion.
ROE VERSUS WADE. The
legality of elective abortion was established by the United States Supreme Court in its 1973 decision in
Roe v Wade. It defined the extent
to which states might regulate abortion:
(a) For the stage prior to approximately the end of the first
trimester, the abortion decision and its effectuation must be left to the
medical judgment of the attending
physician.
(b) For the stage subsequent to approximately the end of the first
trimester, the State, in promoting its interest in the health of the mother,
may, if it chooses, regulate
the abortion procedures in ways that are reasonably related to
maternal health.
(c) For the stage subsequent to viability, the State, in promoting
its interest in the potential of human life, may, if it chooses, regulate, and
even proscribe, abortion,
except where necessary, in appropriate medical judgment, for the
preservation of the life or health of the mother.
WEBSTER VERSUS REPRODUCTIVE HEALTH SERVICES. Since the Roe v Wade decision, many different pieces of
legislation, both state and national, have been
introduced, and some enacted, to regulate or even dismantle its
three provisions. All such attempts were unsuccessful until the United States Supreme Court ruled in
the 1989 Webster v Reproductive
Health Services that states could place
restrictions interfering with provision of abortion services on such items as
waiting periods,
specific informed consent requirements, parental/spousal
notification, and hospital requirements. Based upon this decision, numerous
challenges have arisen to limit
a woman's choice and access to abortion services.
PLANNED PARENTHOOD OF SOUTHEASTERN PENNSYLVANIA VERSUS ROBERT P.
CASEY. In 1992, the
United States Supreme Court considered whether a
state could require, prior to an abortion, a woman's informed
consent, a 24-hour waiting period, spousal consent, parental consent in the
case of a minor, and a
physician's description of the fetus and the abortion technique to
be employed. In a 5 to 4 decision, the court upheld a state's right to require
all these except spousal
consent. The court also reconsidered and reaffirmed the Roe v
Wade decision by a 5 to 4 vote.
STENBERG VERSUS CARHART. The United States Supreme Court in 2000 considered whether the state of Nebraska, as represented by
Attorney General Don
Stenberg, could by state law prevent the performance of so-called
"partial birth abortions," and specifically those performed by Dr.
Leroy Carhart. The court, in a 5 to
4 decision, struck down the Nebraska law. The court ruled that the
Nebraska law was too broad, and that such a prohibition could jeopardize
abortions that involve
more common surgical procedures. The court also noted that the
Nebraska law "would place some women at unnecessary risk" because it
did not include a health
exception.
HILL VERSUS COLORADO. In this 6
to 4 decision rendered also in 2000, the United States Supreme Court upheld the
1993 Colorado statute that is used to regulate
speech-related conduct within 100 feet of the entrance to any
health-care facility. The specific portion of the statute that was challenged
by Leila J. Hill and others
dealt with the provision that made it unlawful to "knowingly
approach" within 8 feet of another person without that person's consent
"for the purpose of passing a
leaflet or handbill to, displaying a sign to, or engaging in oral
protest, education, or counseling with such other person. . . ."
The Colorado law had been enacted to prevent the disruption of
normal functions at medical facilities by protests conducted for any reason.
The Supreme Court's
decision to uphold the Colorado law does not prevent protests
against abortion facilities, but it certainly reduces the likelihood of
confrontations between patients and
demonstrators. That is, the court noted that the Colorado law
insured "the right to be left alone" and did not violate the First
Amendment because the law is "content
neutral."
COUNSELING BEFORE ELECTIVE ABORTION. There are only three choices available to the woman considering an
abortion. These are continued pregnancy with
its risks and responsibilities; continued pregnancy with its risks
and arranged adoption; or the choice of abortion with its risks. In any event,
knowledgeable and
compassionate counselors are invaluable. For instance, women who
delay abortion decisions to later gestational ages have been shown to exhibit
greater
disturbances in the basic sense of self as noted in indications of
gender/sexual conflict and lower achievement or striving orientation ( Cancelmo and associates,
1992).
ABORTION TECHNIQUES
Abortion can be performed either medically or surgically. In a
randomized comparison of the efficacy and acceptability of these techniques, Creinin (2000) reported
that medical abortion seemed to be slightly less costly than
surgical techniques. Paul and colleagues (1999)
have provided detailed summaries for each method
shown in Table 33-5.
Prior to an elective abortion, if bacterial vaginosis is found,
the woman should be treated with metronidazole to reduce the postoperative
infection rate ( Larsson and
colleagues, 1992). Vaginal application
of 2 percent clindamycin cream for 3 days reduces postabortion pelvic infection
fourfold compared with placebo ( Larsson
and
co-workers, 2000). Treatment of
D-negative women after abortion with anti-D immunoglobulin is recommended,
because about 5 percent of D-negative women
become sensitized after an abortion ( Chap. 39, p. 1066).
Goldstein and associates (1994) emphasized
the utility of both ultrasound and immediate tissue examination in 674 women
undergoing elective first-trimester
abortion. Each woman was scanned with an empty bladder using the
transabdominal technique. If no gestational sac was seen, endovaginal
sonography was
performed. All specimens underwent modified gross examination at
33 times magnification and tissue was sent for histopathological analysis.
Transabdominal
sonogram demonstrated uterine gestational tissue in 612 women (91
percent) and 595 of these were less than 12 weeks. There were 17 women (2.5
percent) who
were 13 weeks or greater. In 62 women (9 percent) with no sac seen
transabdominally, endovaginal ultrasound showed 34 uterine and two unruptured
ectopic
pregnancies. Of the remaining women, chorionic villi (17) and
decidua without villi (4) were seen on tissue examination. Of the latter four,
two had rising serum hCG4
levels and were diagnosed with ectopic pregnancy, and two with
falling levels were managed expectantly.
SURGICAL TECHNIQUES FOR ABORTION
The pregnancy may be removed surgically through an appropriately
dilated cervix or transabdominally by either hysterotomy or hysterectomy.
DILATATION AND CURETTAGE. Surgical
abortion is performed by first dilating the cervix and then evacuating the
pregnancy by mechanically scraping out the
contents (sharp curettage), by vacuum aspiration (suction
curettage), or both. The technique for early manual vacuum has been recently
reviewed by MacIsaac and
Jones (2000). The likelihood of
complications—including uterine perforation, cervical laceration, hemorrhage,
incomplete removal of the fetus and placenta, and
infection—increases after the first trimester. For this reason,
curettage or vacuum aspiration should be performed before 14 weeks.
After 16 weeks, dilatation and evacuation (D & E) is
performed. This consists of wide cervical dilatation followed by mechanical
destruction and evacuation of fetal
parts. With complete removal of the fetus, a large-bore vacuum curette
is used to remove the placenta and remaining tissue. A dilatation and
extraction (D & X) is
similar to a D & E5 except that with a D & X6, part of the fetus is first extracted through the dilated cervix
to facilitate the procedure.
In the absence of maternal systemic disease, pregnancies are
usually terminated by curettage or by evacuation or extraction without
hospitalization. When abortion is
not performed in a hospital setting, it is imperative that
capabilities for effective cardiopulmonary resuscitation be available, and that
immediate access to
hospitalization be possible.
HYGROSCOPIC DILATORS. Trauma from
mechanical dilatation can be minimized by using a device to slowly dilate the
cervix. These devices draw water from
cervical tissues and also are used for preinduction cervical
ripening ( Chap. 20, p. 473). Laminaria tents are commonly used to help dilate the cervix ( Fig. 33-8). They
are made from the stems of Laminaria digitata or Laminaria
japonica, a brown seaweed. The stems are cut, peeled, shaped, dried,
sterilized, and packaged according
to size (small, 3 to 5 mm diameter; medium, 6 to 8 mm; and large,
8 to 10 mm). The strongly hygroscopic laminaria are thought to act by drawing
water from
proteoglycan complexes, causing them to dissociate and thereby
allowing the cervix to soften and dilate.
Synthetic hygroscopic dilators have also been used. Lamicel is
a polyvinyl alcohol polymer sponge impregnated with anhydrous magnesium sulfate
( Nicolaides and
co-workers, 1983). Stornes and Rasmussen (1991) reported
that although both lamicel tents and gemeprost pessaries were effective for
cervical dilatation
preparatory to first-trimester abortions, further dilatation was
significantly easier after gemeprost.
Dilapan is made of hydrogel polymer,
and while it was used for some time, it is not available now in the United
States. It has been claimed that it dilates the cervix
more rapidly than dilators made of traditional seaweed ( Blumenthal, 1988; Chvapil and co-workers, 1982). Patsner (1996) found same-day Dilapan
insertion
successful in preparing the cervix for dilatation and evacuation
for second-trimester abortion. Hern (1994) compared Dilapan with laminaria in 1001 women as
overnight dilators. Although both were equally effective dilators,
women receiving the Dilapan were at least twice as likely to experience
problems in cervical dilatation
or problems resulting from poor dilatation or disintegration of
the device than women who used the seaweed preparation.
An interesting dilemma is presented by the woman who has an
osmotic dilator placed overnight preparatory to elective abortion, but who then
changes her mind.
Among seven first-trimester and 14 second-trimester pregnancies in
which this occurred, the dilator was removed and 14 had term deliveries, two
had preterm
deliveries, and one had a spontaneous abortion 2 weeks later ( Schneider and associates, 1991 ).
None suffered infectious morbidity, including three un-treated
women with cervical cultures positive for chlamydia.
TECHNIQUE FOR INSERTION. The
cleansed cervix is grasped anteriorly with a tenaculum. The cervical canal is
carefully sounded, without rupturing the
membranes, to identify its length. A laminaria of appropriate size
is then inserted so that the tip rests just at the level of the internal os
using a uterine packing forceps
or a radium capsule forceps (Fig. 33-8). Later, usually after 4 to 6 hours, the laminaria will have
swollen and thereby dilated the cervix sufficiently to allow easier
mechanical dilatation and curettage. The laminaria may cause
cramping.
PROSTAGLANDINS. Rather than
using a hygroscopic dilator to effect cervical softening, prostaglandin
pessaries (suppositories) have been inserted into the vagina
against the cervix 3 hours or so before attempting dilatation. Chen and Edler (1983) reported
good results from applying 1 mg of prostaglandin E 1 methyl ester.
Several newer prostaglandin products have been used to induce
labor or to efface the cervix prior to labor induction. Many of these same
products have also been
used to prepare the cervix prior to mechanical dilatation for
induction of abortion. These prostaglandins are also discussed in Chapter 20 (p. 471).
TECHNIQUE FOR DILATATION AND CURETTAGE. The anterior cervical lip is grasped with a toothed tenaculum. A
local anesthetic such as 5 mL of 1 or 2 percent
lidocaine is injected bilaterally into the cervix. Alternatively,
a paracervical block may be used.
The uterus is sounded carefully to identify the status of the
internal os and to confirm uterine size and position. The cervix is further
dilated with Hegar or Pratt dilators
until a vacuum aspirator suction curet of appropriate diameter can
be inserted. As shown in Figure 33-9, the fourth and fifth fingers of the hand introducing the dilator
should rest on the perineum and buttocks as the dilator is pushed
through the internal os. This provides a further safeguard against uterine
perforation.
Suction curettage then is used to aspirate pregnancy products. The
vacuum aspirator is moved over the surface systematically in order eventually
to cover all the
uterine cavity. Once this is done and no more tissue is aspirated,
then gentle sharp curettage is done if it is thought that any placenta or fetal
fragments remain. A
sharp curet is more efficacious, and its dangers need not be
greater than those of the dull instrument. Uterine perforations rarely occur on
the downstroke of the curet,
but they may occur when any instrument is introduced into the
uterus. As shown in Figure 33-10, manipulations should be carried out with the thumb and
forefingers
only.
In cases advanced past 16 weeks, the fetus is extracted, usually
in parts, using Sopher or similar forceps and other destructive instruments.
These late abortions are
unpleasant for medical and nursing personnel and more dangerous
for the woman undergoing the procedure. The risks of uterine perforation and
laceration are
increased due to the larger fetus and the thinner uterine walls.
It is reemphasized that morbidity, immediate and remote, will be
kept to a minimum if:
1. The cervix is adequately
dilated without trauma before attempting to remove the fetus and gestational
tissues.
2. Removal of the pregnancy is
accomplished without perforating the uterus.
3. All pregnancy tissue is
removed.
UTERINE PERFORATION. Accidental
uterine perforation may occur during sounding of the uterus, dilatation, or
curettage. The incidence of uterine perforation
associated with elective abortion varies. Two important
determinants of this complication are the skill of the physician and the
position of the uterus, with a much
greater likelihood of perforation if the uterus is retroverted.
Accidental uterine perforation is recognized easily, as the instrument passes
without hindrance further than
it should have. Observation may be sufficient therapy if the
uterine perforation is small, as when produced by a uterine sound or narrow
dilator.
Considerable intra-abdominal damage can be caused by instruments
passed through a uterine defect into the peritoneal cavity. This is especially
true for suction and
sharp curets. In this circumstance, laparotomy to examine the
abdominal contents, especially the bowel, is the safest course of action.
Unrecognized bowel injury
causes severe peritonitis and sepsis ( Kambiss and associates, 2000). We have also
cared for a woman transferred to us after much of her right ureter had been
removed at the time of attempted abortion using suction curettage!
Similar cases have been observed by others ( Keegan
and Forkowitz, 1982).
Some women may develop cervical incompetence or uterine synechiae
following dilatation and curettage. The possibility of these complications
should be explained
to those contemplating abortion. In general, their risk is very
slight. Unfortunately, more advanced abortion performed by curettage may induce
sudden, severe
consumptive coagulopathy, which can prove fatal.
MENSTRUAL ASPIRATION. Aspiration
of the endometrial cavity using a flexible 5- or 6-mm Karman cannula and
syringe within 1 to 3 weeks after a missed
menstrual period has been referred to as menstrual extraction,
menstrual induction, instant period, traumatic abortion, and mini-abortion.
Problems include the woman
not being pregnant, the implanted zygote being missed by the
curet, failure to recognize an ectopic pregnancy, and rarely, uterine
perforation.
A positive pregnancy test will eliminate a needless procedure on a
nonpregnant woman whose period has been delayed for other reasons. MacIsaac and Jones
(2000) recommend the following
technique for identifying placenta in the aspirate. First, the syringe contents
are placed in a clear plastic container and examined with
back lighting. Tap water is used to wash the tissue held in a
strainer. The tissue is immersed in clear water. Placenta is macroscopically
soft, fluffy, feathery, and
villous. A magnifying lens or culposcope provides visualization.
If there is doubt as to whether the tissue is placenta or decidua, microscopic
examination of a small
piece under a cover glass with high-light contrast will allow
differentiation. Placental villi are obvious.
LAPAROTOMY. In a few
circumstances, abdominal hysterotomy or hysterectomy for abortion is preferable
to either curettage or medical induction. If significant
uterine disease is present, hysterectomy may provide ideal
treatment. If sterilization is to be performed, either hysterotomy with tubal
ligation or hysterectomy on
occasion may indicated. At times, hysterotomy or hysterectomy
becomes necessary because of failure of a medical induction during the second
trimester.
MEDICAL INDUCTION OF ABORTION
Throughout history, many naturally occurring substances have been
tried as abortifacients by women desperate not to be pregnant. Most often,
serious systemic
illness or even death has been the result rather than abortion.
Even today, there are only a few effective, safe abortifacient drugs.
OXYTOCIN. Successful induction of
second-trimester abortion is possible with high doses of oxytocin administered
in small volumes of intravenous fluids. One
regimen we have found effective is to add 10 1-mL ampules of
oxytocin (10 IU/mL) to 1000 mL of lactated Ringer solution. This solution
contains 100 mU oxytocin per
mL. An intravenous infusion is started at 0.5 mL/min (50 mU/min).
The rate of infusion is increased at 15- to 30-minute intervals up to a maximum
rate of 2 mL/min
(200 mU/min). If effective contractions are not established at
this infusion rate, the concentration of oxytocin is increased in the infused
solution. It is safest to discard
all but 500 mL of the remaining solution, which contains a
concentration of 100 mU oxytocin per mL. To this 500 mL is added an additional
five ampules of oxytocin.
The resulting solution now contains 200 mU/mL, and the rate of
infusion is reduced to 1 mL/min (200 mU/min). A resumption of a progressive
rate increase is
commenced up to a rate of 2 mL/min (400 mU/min) and left at this
rate for an additional 4 to 5 hours, or until the fetus is expelled.
Similar regimens have been shown to be highly effective by Winkler (1991) and Owen (1992) and their associates.
In a retrospective comparison of prostaglandin E 2
(PGE2) vaginal suppositories and high-dose oxytocin, Winkler and colleagues (1991) reported
successes of 93 percent and 91 percent, respectively. The mean
duration of labor was 13.1 hours with PGE 2 and 8.2 hours with
oxytocin. The mean dose of PGE2 was 65 mg and of oxytocin was 200 units. Side
effects were limited
to the PGE2 group, with nausea (46 percent), vomiting (37
percent), fever (64 percent), and diarrhea (20 percent).
In a subsequent randomized trial, Owen
and co-workers (1992) concluded that concentrated
oxytocin is a satisfactory alternative to prostaglandin E 2 for midtrimester
abortion. The same group also compared concentrated oxytocin plus
low-dose prostaglandin with prostaglandin E 2 vaginal suppositories for second
trimester
terminations (Owen and Hauth, 1996). The women in the prostaglandin-only group received a 20-mg PGE
2 vaginal suppository every 4 hours, and those in the
combined group received a 10-mg PGE2 suppository every 6 hours.
The success rate was 81 versus 89 percent, but the side effects were
significantly higher for the
vaginal PGE2-only group. In a more recent trial, the Alabama group
compared vaginal misoprostol (200 ug vaginally every 12 hours) with a regimen
of concentrated
oxytocin plus 10-mg PGE2 suppositories every 6 hours (Owen and Hauth, 1999). They
concluded that misoprostol vaginal tablets in this dose were not satisfactory
for
second-trimester pregnancy termination.
With concentrated oxytocin, careful attention must be directed to
the frequency and intensity of uterine contractions, because each increase in
infusion rate markedly
increases the amount of oxytocin infused. If the initial induction
is unsuccessful, serial inductions on a daily basis for 2 to 3 days are almost
always successful. The
chance of a successful induction with high-dose oxytocin is
enhanced greatly by the use of hygroscopic dilators such as laminaria tents
inserted the night before.
INTRA-AMNIONIC HYPEROSMOTIC SOLUTIONS. In order to effect abortion during the second trimester, 20 to 25
percent saline or 30 to 40 percent urea have been
injected into the amnionic sac to stimulate uterine contractions
and cervical dilatation. These techniques are used infrequently in the United
States, and according to
the American College of
Obstetricians and Gynecologists (1987) , they have
been replaced by dilatation and evacuation. Benefits of the latter cited
included speed,
lower cost, and less pain and emotional trauma.
In a study from Thailand, among 125 pregnancies undergoing
midtrimester termination using hypertonic saline, the mean
induction-to-delivery time was 31.7 hours
(Herabutya and O-Prasertsawat, 1994). Retained placenta developed in 63 percent and pyrexia in 39
percent. In a study from India, Allahbadia
(1992) reported
success rates of 96 percent in pregnancies ranging from 14 to 20
weeks when 200 mL of 20 percent saline was instilled. This compared favorably
with a success rate
of 90 percent with intramuscular PGF2a, and 100 percent with
extra-amnionic instillation of 5 percent povidone-iodine mixed with normal
saline.
Hypertonic saline may result in serious complications, including
death ( Jasnosz and colleagues, 1993). Other
complications include:
1. Hyperosmolar crisis following
entry of hypertonic saline into the maternal circulation.
2. Cardiac failure.
3. Septic shock.
4. Peritonitis.
5. Hemorrhage.
6. Disseminated intravascular
coagulation.
7. Water intoxication.
HYPEROSMOTIC UREA. Urea, 30 to
40 percent, dissolved in 5 percent dextrose solution, has been injected into
the amnionic sac, followed by intravenous oxytocin
at about 400 mU/min. Urea plus oxytocin is as efficacious an
abortifacient as hypertonic saline, but is less likely to be toxic. Urea plus
prostaglandin F 2a injected into
the amnionic sac is similarly effective.
PROSTAGLANDINS. Because of
shortcomings of other medical methods of inducing abortion, prostaglandins and
their analogues are used extensively to terminate
pregnancies, especially in the second trimester. Compounds
commonly used are prostaglandin E 2, prostaglandin F2a, and certain analogues,
especially
15-methylprostaglandin F2a methyl ester, PGE1-methyl ester
(gemeprost), and misoprostol. Mechanisms of action of the prostaglandins are
considered in detail in
Chapter 20 (p. 471).
TECHNIQUE. Prostaglandins can act
effectively on the cervix and uterus when:
1. Placed in the vagina as a
suppository or pessary immediately adjacent to the cervix.
2. Administered as a gel
through a catheter into the cervical canal and lowermost uterus extraovularly.
3. Injected intramuscularly.
4. Injected into the amnionic
sac by amniocentesis.
5. Taken orally.
Various treatment regimens are outlined in Table 33-6.
Christin-Maitre and colleagues
(2000) provided a recent update on the medical termination of pregnancy.
They reviewed numerous studies regarding the efficacy and
side effects of prostaglandins and methotrexate utilized alone or
in various combinations. They also reviewed the efficacy and side effects of
mifepristone utilized with
a prostaglandin. Kahn and associates
(2000) provided a meta-analysis regarding medical abortion with
mifepristone and misoprostol, mifepristone with other
prostaglandins, and methotrexate with misoprostol. They concluded
that these regimens had high levels of success for early gestations. Parenteral
approaches
reduce appreciably, but do not eliminate, the unpleasant systemic
effects, especially gastrointestinal, that accompany oral administration.
Repeated doses of
prostaglandin are often required and hygroscopic cervical dilators
are often used concurrently.
Effectiveness of the various treatment regimens has ranged from 86
to 95 percent. Induction-to-delivery intervals ranged from 4 hours to more than
48 hours. In one
study of 932 second-trimester terminations using gemeprost, the
median induction-to-abortion interval was 18 hours in nulliparas and 15 hours
in parous women
(Thong and associates, 1992).
Prostaglandin vaginal suppositories applied to the cervix are also
used in a lower dose during the first and early second trimesters to ripen or
soften and dilate the
cervix before curettage or as an adjunct for mifepristone
termination ( Healy and Evans, 1994). The safety of late induced abortion after a previous cesarean
delivery
using prostaglandins or mifepristone was reported by Boulot and associates (1993). At a mean
gestational age of almost 24 weeks, vaginal evacuation was achieved
in 20 of 23 women. At hysterotomy in the three treatment failures,
one uterine rupture was found and successfully repaired. Chapman and colleagues (1996) reported
a uterine rupture rate of 3.8 percent in 79 women undergoing
termination by induction at a mean age of 21 weeks.
MIFEPRISTONE (RU 486). This oral
antiprogesterone has been used to effect abortions in early gestation, either
alone or in combination with oral prostaglandins
(Baird and colleagues, 1992; el-Refaey and associates,
1995; Newhall and Winikoff, 2000; World Health Organization
Task Force, 1994 ). The effectiveness of the
drug as an abortifacient is based upon its high receptor affinity
for progesterone-binding sites ( Healy and
colleagues, 1983). A single 600-mg dose of
RU 486
administered prior to 6 weeks results in an 85 percent abortion
rate. In first trimester nondeveloping pregnancies, a single dose of 600-mg of
mifepristone induced
expulsion in 82 percent of women (Lelaidier
and co-workers, 1993).
Ulmann and associates (1992) reported
their results from over 16,000 women in whom RU 486 was given followed by a
prostaglandin analogue for medical
termination. Overall success rate was 95 percent, with no
difference regarding the nature or dose of prostaglandin used. Median duration
of bleeding was 8 days and
it was 12 days or less in 90 percent of women. Bleeding
necessitated vacuum aspiration or curettage in 0.8 percent of cases.
Transfusion was required in 1 per 1000
women.
As discussed in Chapter 58 (p. 1548), RU 486 is also highly effective for emergency postcoital
contraception if given within 72 hours ( Glasier
and associates, 1993 ).
After 72 hours, the agent is progressively less effective. The
addition of various oral, vaginal, or injected prostaglandins to this regimen
results in abortion rates over
95 percent.
Side effects of RU 486 include nausea, vomiting, and gastrointestinal
cramping. The major associated risk is hemorrhage due to partial expulsion of
the pregnancy
and due to intra-abdominal hemorrhage from an early unsuspected
ectopic pregnancy. The duration of vaginal bleeding is approximately 2 weeks
after RU 486 alone
and approximately 1 to 2 weeks after RU 486 is given with a
prostaglandin.
EPOSTANE. This 3ß-hydroxysteroid
dehydrogenase inhibitor block the synthesis of endogenous progesterone. If
administered within 4 weeks of the last menstrual
period, the drug will induce an abortion in approximately 85
percent of women ( Crooij and associates,
1988). Clinical responses are likely related to circulating
endogenous progesterone levels. Nausea is a frequent side effect,
and hemorrhage is a risk if the abortion is incomplete. Other antiprogestins
such as ZK 98,734 are
under study, and appear to be promising for induction of early
abortion ( Swahn and colleagues, 1994).
CONSEQUENCES OF ELECTIVE ABORTION
MATERNAL MORTALITY. Legally
induced abortion is a relatively safe surgical procedure, especially when
performed during the first 2 months of pregnancy. The
risk of death from abortion performed during the first 2 months is
about 0.6 per 100,000 procedures ( Berg and
co-workers, 1996; Centers for Disease Control, 1986;
Grimes, 1994). The relative risk of
dying as the consequence of abortion is approximately doubled for each 2 weeks
of delay after 8 weeks' gestation. Atrash
and
colleagues (1988) reported
that the proportion of abortion-related deaths caused by general anesthesia had
increased from 8 percent in 1975 to 29 percent in 1985.
This likely reflects an absolute decrease in deaths from
nonanesthetic complications. LeBolt and co-workers
(1982) estimated that during the 1970s, overall risk of
death from legal abortion was 15 percent of the risk from
childbirth. Indeed, in 1987 six maternal deaths were reported among 1.3 million
legal abortions ( Grimes,
1994). In his recent review, de Swiet (2000) emphasized that prior
to the United Kingdom Abortion Act in 1968, 40 percent of maternal deaths were
due to criminal
abortion. In 1994 through 1996, only 4 percent of deaths were
related to abortion, and none were illegal.
IMPACT ON FUTURE PREGNANCIES. Hogue (1986), in a scholarly review
of the impact of elective abortion upon subsequent pregnancy outcome,
summarized data
from more than 200 publications. She emphasized that consideration
must be given for the method of inducing abortion, and that women chosen as
controls should be
nulliparous because parous women had a reduced risk of
complications in subsequent pregnancies.
Fertility is not altered by an elective abortion. A possible
exception is the small risk from pelvic infection. Vacuum aspiration results in
no increased incidence of
midtrimester spontaneous abortions, preterm deliveries, or
low-birthweight infants in subsequent pregnancies. Dilatation and curettage,
however, in primigravidas
results in an increased risk for subsequent ectopic pregnancy,
midtrimester abortion, and low-birthweight infants.
Subsequent ectopic pregnancies are not increased if the first
termination is done by vacuum aspiration. Possible exceptions are in women with
preexisting chlamydial
infection or those who develop postabortion infection. Multiple
elective abortions do not increase the incidence of preterm delivery and
low-birthweight infants
(Mandelson and associates, 1992). Placenta previa was reported to be increased following elective
abortion ( Barrett and associates, 1981). Hogue (1986) discounted
this study because of failure to control for maternal age.
Induced midtrimester abortions apparently carry little risk to
subsequent pregnancies if injection techniques are used. There are not enough
procedure-specific data
available to permit valid conclusions regarding the risks to
future pregnancies following any midtrimester abortion.
SEPTIC ABORTION
Serious complications of abortion have most often been associated
with criminal abortion. Severe hemorrhage, sepsis, bacterial shock, and acute
renal failure have
all developed in association with legal abortion but at a very
much lower frequency. Metritis is the usual outcome, but parametritis,
peritonitis, endocarditis, and
septicemia may all occur (Vartian
and Septimus, 1991). In 300 septic abortions
at Parkland Hospital, a positive blood culture was found in a fourth. Almost
two thirds
were anaerobic bacteria and coliforms were also common. Other
organisms reported as causative of septic abortion include Haemophilus
influenzae, Campylobacter
jejuni, and group A streptococcus (Denton and Clarke, 1992; Dotters and Katz, 1991; Pinhas-Hamiel and associates, 1991).
Treatment of infection includes prompt
evacuation of the products of conception along with broad-spectrum
antimicrobials given intravenously. If sepsis and shock supervenes, then
supportive care is
essential as discussed in Chapter
43 (p. 1167). Septic abortion has also been
associated with disseminated intravascular coagulopathy ( Chap. 25, p. 657).
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