Molar pregnancy: Will it happen again?

A molar pregnancy occurs very early in pregnancy when the placenta develops into an abnormal mass (hydatidiform mole) in the uterus. In most cases the embryo never forms. A molar pregnancy is due to chromosomal abnormalities in the fertilized egg (ovum). About 1 in 1,000 pregnancies in the United States and Europe is molar. This rate is higher in Asian countries. Also, women who are older than age 40 are at increased risk of a molar pregnancy.

Signs and symptoms of a molar pregnancy include:

• Vaginal bleeding in pregnancy
• An abnormally large uterus for the length of pregnancy
• Severe nausea and vomiting

If you have these signs and symptoms, contact your doctor promptly. A doctor may make a diagnosis by ultrasound examination.

Treatment involves removing the tissues from the uterus using suction curettage. In this procedure, the cervix is dilated and the tissues are removed by gentle suction. After the procedure, your doctor will monitor your levels of the pregnancy hormone human chorionic gonadotropin (HCG) for an extended time to make sure that no molar tissue remains. Occasionally, a mole can become cancerous.

Following a molar pregnancy, women are advised not to become pregnant for at least a year. If you've had a molar pregnancy, you have a slightly increased risk of a second one. But most women have successful subsequent pregnancies.