Classification and Differential
Diagnosis of Spontaneous Abortions
Because the differential diagnosis of bleeding in the first trimester of pregnancy includes a wide range of possibili-ties, such as ectopic pregnancy, hydatidiform mole, cervi-cal polyps, cervicitis, and neoplasm, the patient should be examined whenever there is bleeding in early pregnancy.
abortion is characterized by bleeding in thefirst trimester
without loss of fluid or tissue. About half of women with a threatened abortion
proceed to spontaneous abortion. Those who carry to viability a pregnancy
compli-cated by threatened abortion are at greater risk for preterm delivery
and an infant of low birth weight. There does not, however, appear to be a
higher incidence of congenital malformations in these newborns. Some patients
describe bleeding at the time of their expected menses, sometimes referred to
as implantation bleeding, which may
be re-lated to implantation of the embryo in the endometrium.
In cases of miscarriage, bleeding
usually begins first, and cramping abdominal pain follows a few hours to
several days later. The pain may present as anterior and clearly rhythmic
cramps; as a persistent low backache, as-sociated with a feeling of pelvic
pressure; or as a dull, mid-line, suprapubic discomfort. The combination of bleeding
and pain usually indicates a poor prognosis for pregnancy continuation.
pregnancy should always be considered in the differ-ential diagnosis of
An inevitable abortion is the gross rupture of the membranes in the
presence of cervical dilation. Typically, uterine contractions begin promptly,
resulting in expul-sion of the products of conception. It is unusual for a
preg-nancy to successfully reach viability in this circumstance. Conservative
management of these patients significantly increases the risk of maternal
During an incomplete abortion, the internal cervical os opens and allows
passage of blood. The products of con-ception may remain entirely in utero or
may partially ex-trude through the dilated os. Before 10 weeks, the fetus and
placenta are commonly expelled together, but later they are delivered
separately. In many cases, retained placental tis-sue remains in the cervical
canal, allowing easy extraction from an exposed external os with ring forceps. If
unsuccess-ful, a suction curettage effectively evacuates the uterus.
abortion refers to a documented preg-nancy that
spontaneously passes all of the products of con-ception. Before 10 weeks, the
fetus and placenta are often expelled in toto.
abortion is the retention of a failed intra-uterine
pregnancy for an extended period, usually defined as more than two menstrual
cycles. These patients have an absence of uterine growth and may have lost some
of the early symptoms of pregnancy.
Many women have no symptoms
during this period except persistent amenorrhea. If the missed abortion
ter-minates spontaneously, and most do, the process of expul-sion is the same
as in any abortion.
pregnancy loss is a term used when a patienthas had more than two
consecutive pregnancy losses. The timing of the pregnancy losses may provide a
clue to their cause. Genetic factors most frequently result in early em-bryonic
losses, whereas autoimmune or anatomic abnor-malities are more likely to result
in second-trimester losses. Karyotyping is recommended for both parents when
re-current early abortion occurs, because there is a 3% chance that one parent
is a symptomless carrier of a genetically balanced chromosomal translocation.
When recurrent pregnancy losses
occur later than the first trimester of pregnancy, they can be caused by
maternal medical conditions or anatomic anomalies, which may be treatable.
Uterine anomalies, such as septate uteri, can be related to fetal wastage. In
these cases, management includ-ing hysterography, operative hysteroscopy, or
laparoscopy may be required to correct the problem. Intrauterine synechiae
associated with Asherman syndrome may occur after a curettage procedure has
denuded the endometrium past the layer of the basalis, so that webs of scar
tissue de-velop across the uterine cavity (the synechiae). Asherman syndrome is
associated with amenorrhea or irregular menses, infertility, and recurrent
pregnancy loss. The diag-nosis is confirmed by a hysterogram that shows the
charac-teristic webbed pattern or by hysteroscopy. Treatment involves lysis of
the synechiae and postoperative treatment with high doses of estrogen to
facilitate endometrial prolif-eration, leading to the reestablishment of a normal
Much attention has focused on the
immune system and its role in recurrent pregnancy loss. Antiphospho-lipid antibodies are a family of autoantibodies that
bindto negatively charged phospholipids. Lupus anticoagulant and anticardiolipin
antibody have been linked with exces-sive pregnancy wastage. Treatment may
include low-dose aspirin along with unfractionated heparin This therapy, begun
when pregnancy is diagnosed, may be continued until delivery. Other immunologic
defects associated with recurrent miscarriage are factor V Leiden defect and
pro-thrombin gene mutation.