I saw a woman once for an initial visit. There was nothing really remarkable about her history or physical condition. She was 31 years old and pregnant for the first time. The only significant piece of the history of the pregnancy to date was her persistent nausea. At ten weeks, she had already lost five pounds. She had also experienced some scant spotting early in the pregnancy, which had resolved.

Her physical exam was unremarkable except that her uterus was approximately 14 to 16 week size. She was either mistaken about her dates, had twins or I was wrong about her uterine size. The idea of a molar pregnancy filtered through my mind, but I tried to dismiss it.

Even when I could not hear fetal heart tones, I was not especially concerned. We do not always hear them as early as ten weeks. As I reviewed the ultrasound report a few days later, I acknowledged that her pregnancy had the classic signs and symptoms of a molar pregnancy or hydatidiform mole.

A molar pregnancy most often occurs at the extremes of reproductive life -- usually in women over the age of 40. In the general population, the risk is 1 in 1000 to 1 in 1500. Most molar pregnancies occur after an ectopic pregnancy, after a pregnancy loss or even after a full term pregnancy.

There are several classifications of gestational trophoblastic disease, of which hydatidiform mole (complete molar pregnancy) is one type. The Other type is known as a partial mole.

When fertilizaton occurs and there is no genetic information within the egg cell (so called "empty egg"), the resulting condition is known as a complete molar pregnancy. Rapid cell production occurs only within the cells which form the placenta and there is high production of the placental hormone human chorionic gonadoptropin (hCG). Such high levels of hCG account for the positive pregnancy test and the extreme nausea.

When two sperm fertilize an egg, a partial mole forms. Instead of Forming twins, something goes wrong, leading to a pregnancy with an abnormal fetus and an abnormal placenta. The baby has too many chromosomes (two full sets from the father and none from the mother) and almost always dies in the uterus. Ultrsound can verify if a molar pregnancy exists and whether or not it is a complete or partial. Rarely, a normal fetus may also coexist with a molar pregnancy. Management of such pregnancies are at high risk for pregnancy loss and for the development of pregnancy induced hypertension. Consultation or care by an obstetrician or perinatologist would be recommended.

Signs and symptoms of a molar pregnancy

1. Normal first trimester symptoms
2. Persistent nausea and vomiting
3. Bleeding by 12th week (continuous or intermittent, usually light)
4. "Large for dates" are typical, although about 25 percent may be "small for dates"
5. No fetal heart tones or fetal movement
6. Hypertension may become a problem in the second trimester
7. Shortness of breath (late, life threatening indication of an embolism)
8. Enlarged, tender ovaries (ovarian cysts)
9. Passage of "grape-like" vesicles with bleeding

Diagnosis of a molar pregnancy is made by ultrasound and by elevated beta hCG levels. There is a rare risk (two percent) of choriocarcinoma (cancer) following molar pregnancy. Benign tumor formation may also occur.

Treatment involves evacuation, usually with suction curettage, of the vesicles within the uterus. Lab studies might include serial beta hCG levels, blood clotting studies, liver and thyroid profiles, hemoglobin, and chest X-ray.

Beta hCG levels are drawn every one to two weeks until resolved and then they may be done on a regular schedule for the year following the loss.

Because the risk of cancer needs to be fully evaluated, effective contraception should be used for one year following the pregnancy. Regular visits for a physical and pelvic exams are made until the uterus and ovaries are back to normal. Thereafter, they are generally done every three months for the next year.

In subsequent pregnancies, the woman may be at higher risk of another molar pregnancy, so she is followed closely with serial hCG levels and ultrasound.

Experiencing a molar pregnancy is extremely stressful for the woman, her partner and family. Not many people understand the physiology of such a pregnancy. It is generally best to tell loved ones that a miscarriage has occurred and that special followup lab work is necessary. When the pregnancy itself has been "ambiguous" and the life of the mother has been at risk, it may be harder to understand and disclose all of the details.

A good resource for those seeking more information is the March of Dimes Ectopic and Molar Pregnancy Fact Sheet