There are three main types of abnormal pregnancies. These include an early pregnancy
failure, an ectopic pregnancy, and a molar pregnancy. It is important to know the signs
and symptoms of abnormal pregnancies, so that you can seek our medical attention, if
you believe you are at risk.
Early Pregnancy Failure
This abnormal pregnancy occurs when there is a failure in the embryonic growth. This
can be detected through an ultrasound. The image would appear as a large gestational
sac, and this would signify that the growth of the embryo had failed. There are usually
no symptoms of this condition, except some bleeding or cramps.
This condition occurs when the fertilized egg implants outside of the uterus. Ninety-five
percent of the time, the egg would settle in the fallopian tubes; however, it is also
possible for the egg to settle in the ovary, abdomen, or the cervix. Unfortunately, none
of these organs have enough space or nurturing tissue for the pregnancy to develop.
This can be very dangerous, because if the embryo does happen to grow, it could
endanger surrounding organs of the mother.
If the ectopic pregnancy is discovered early enough, an injection can stop the growth of
the embryo. However, if the abnormal pregnancy is not detected until later, one would
need surgery to remove it.
Warning Side Effects include:
-Sharp or stabbing pain
-Low blood pressure
-Low back pain
The most common signs of an ectopic pregnancy include sharp or stabbing pain and/or
vaginal bleeding. Other symptoms include vaginal spotting, dizziness, low blood
pressure, or low back pain.
Often, a molar pregnancy will mimic a healthy pregnancy. This occurs when a genetic
error takes place during the fertilization process, which leads to the growth of abnormal
tissue within the uterus.
A compete molar pregnancy will result in only a placenta and no baby being formed,
while a partial molar pregnancy will result in several defects to the embryo, and
eventually the fetus will be overcome by the growing abnormal mass. A very rare
version of the partial mole will happen when twins are conceived, with one developing
normally and the other mole. In this case, the healthy embryo will quickly be consumed
by the abnormal growth.
This abnormal pregnancy is very rare, but also very frightening. Only 1 in every 1,000
women in the United States suffer from this condition, with women over the age of 40
being at a higher risk. Women who have had a previous molar pregnancy are also at a
higher risk to have another one.
A molar pregnancy can be detected through a pelvic exam, or by a sonogram.
Warning side effects include:
-High blood pressure levels
-Increased hCG levels
-No fetal movement or heart tone
Early Pregnancy Failure
Early pregnancy failure is characterized by embryonic growth failure. This may be
evident at the time of initial ultrasound for medical abortion. Historically, the
condition was diagnosed when a large, empty gestational sac was visualized on
ultrasound (explaining the older terms "blighted ovum" and "anembryonic
The greater resolution of transvaginal sonography has revealed that early pregnancy
failure is a continuum that can initially appear as an abnormal embryo and eventually
become an empty sac after reabsorption occurs.
Patients with early pregnancy failure may have bleeding and cramping, or they may
have no symptoms. Examination may reveal a uterus smaller than expected for dates;
in the case of an actively bleeding patient, products of conception may be evident in
the cervical os or vagina.
When no intrauterine pregnancy is detected and the serum ß-hCG level is below the
discriminatory zone, the diagnosis could be a failed pregnancy, an ectopic gestation,
or an intrauterine pregnancy that is too small to be detected sonographically. A repeat
sonogram a few days later or serial ß-hCG levels may be required for diagnosis.
A range of ultrasonographic findings is consistent with early pregnancy failure: a
mean gestational sac diameter ≥ 8 mm with no visible yolk sac,
a gestational sac
with a mean diameter ≥ 16 mm with no embryo,
and an embryo with a length > 5
mm with no visible cardiac activity.
Confirmation of the diagnosis by repeat
ultrasonography a few days later or by serial ß-hCG level is prudent when the patient
has any doubts about terminating the pregnancy.
The risk factors for ectopic pregnancy include a history of ectopic pregnancy, pelvic
inflammatory disease, tubal surgery, current use of an intrauterine device, and assisted
reproductive technology. A study of surgical abortion patients published in 1997
reported an ectopic pregnancy rate of 6.7 per 1,000 among women seeking surgical
abortion at < 6 weeks.
Patients with ectopic pregnancy may report some abnormal bleeding since their last
menstrual period. Another common symptom is unilateral pelvic pain of gradual or
sudden onset, which may be mild or severe. Some patients may be completely
asymptomatic. The uterus is typically smaller than expected based on LMP, and an
adnexal mass or tenderness may be detected on pelvic examination.
The discriminatory level can help narrow the diagnostic possibilities. When the serum
ß-hCG level is below the discriminatory level and no intrauterine pregnancy is
detected on ultrasound, the differential diagnosis includes an ectopic gestation, a
failed pregnancy, or an intrauterine pregnancy too small to be detected
sonographically. Conversely, if the ß-hCG concentration exceeds the discriminatory
level and no intrauterine pregnancy is seen on ultrasound, then an ectopic pregnancy
should be considered present until proven otherwise.
Suspicion of an ectopic pregnancy warrants examination by an
experienced sonographer. Because spontaneous heterotopic
pregnancy occurs rarely, sonographic visualization
of an intrauterine gestational sac essentially excludes the
diagnosis of ectopic pregnancy. Conversely, visualization of an
extrauterine yolk sac or embryo with cardiac activity is pathognomonic for the
diagnosis of ectopic pregnancy. However, these findings are detected with
transvaginal ultrasonography in only about 15% to 29% of tubal pregnancies.
Hydatidiform mole, also known as a "molar pregnancy," results from genetic
abnormalities. Molar pregnancies are the benign end of a spectrum of trophoblastic
neoplasia that includes invasive moles and choriocarcinoma. The prevalence in the
United States is approximately 1 per 600 induced abortions.
Risk factors include
extremes of reproductive age, low socioeconomic status, and a history of similar
Abnormal bleeding and nausea or vomiting are the typical symptoms. The uterus may
feel larger than expected for dates. Serum ß-hCG levels can aid in this diagnosis, as
levels of this hormone are often markedly elevated (> 330,000 mIU/mL). In the late
first trimester, complete moles exhibit a classic "snowstorm" or "grape-like"
Unlike the situation in later pregnancy, the sonographic appearance in early pregnancy
may be indistinguishable from that of pregnancy failure. Molar pregnancy is not
generally diagnosable in early pregnancy based on ultrasound findings alone; clinical
guidance is required.
When this disorder is diagnosed during the medical abortion screening process, the
clinician should explain the problem to the patient and arrange for appropriate
treatment. Treatment should include prompt surgical evacuation of the uterus,
examination of the contents by a pathologist to detect possible malignancy, and close
follow-up for 1 year to detect recurrences or progression to gestational trophoblastic
disease or development of choriocarcinoma.