Molar Pregnancy

Christina S. Chu, MD
Last Modified: February 17, 2002

Dear OncoLink "Ask The Experts,"

I had a molar pregnancy in November of 2001. While in school, one of my teachers told me that molar pregnancies are "most of the time" linked to cancer. Is this true? If so why didn't my doctor tell me? I'm only 27 yrs. old and so far all my paps have been normal. Should I be worried?

Christina S. Chu, MD, Assistant Professor of the Division of Gynecologic Oncology at the University of Pennsylvania Health System, responds:

Luckily, molar pregnancies are only associated with "cancer" some of the time. First of all, there are two basic types of molar pregnancies: complete and incomplete. Complete moles have a well-recognized potential for invading the uterine wall, or spreading to other organs. In patients designated high risk (HCG or pregnancy hormone levels greater than 100,000 mIU/ml, excessive uterine enlargement, or the presence of theca lutein cysts of the ovary measuring greater than 6cm in diameter), the chance for developing invasion of the tissue into the uterus is about 30%, with the risk of spread to other parts of the body being about 5-10%. In contrast, patients with low risk complete molar pregnancies and incomplete (or partial) molar pregnancies experience local invasion in only 3-4% of cases, and spread to other organs in less than 1% of cases. When local invasion or spread to other organs occurs, chemotherapy is often very effective treatment.

The usual follow up after the diagnosis of a molar pregnancy involves checking the blood level of HCG, a marker physicians use to follow persistence or recurrence of the disease, to ensure that the level stays negative for at least 6-12 months after initial diagnosis. Patients are usually counseled to use effective contraception during this time. Afterwards, the risk of additional problems is rare, though after having one molar pregnancy, the risk of having another is slightly increased.