A molar pregnancy is a rare complication of pregnancy that occurs when an egg and sperm join incorrectly at fertilization and create a noncancerous tumor. It is also known as a hydatidiform mole. There are two types of molar pregnancy: complete and partial.
- Complete molar pregnancy: In this type, the placental tissue swells and appears to form fluid-filled cysts. There is no fetus.
- Partial molar pregnancy: In this type, the placenta might have both regular and irregular tissue. There may be a fetus, but the fetus cant survive. The fetus usually is miscarried early in the pregnancy.
Molar pregnancies are caused by an imbalance in genetic material (chromosomes) in the pregnancy. The cause of molar pregnancy is unknown, but a key risk factor is maternal age. Women with a molar pregnancy often feel pregnant and may have pregnancy symptoms such as sore breasts or morning sickness because the abnormal placenta often makes higher-than-normal amounts of the pregnancy hormone called human chorionic gonadotropin (hCG) .
If you've had a molar pregnancy, talk to your pregnancy care provider before trying to get pregnant again. You might want to wait six months to one year. The risk of having another molar pregnancy is low, but it's higher once you've had a molar pregnancy. During future pregnancies, a care provider may do early ultrasounds to check your condition.
