Molar Pregnancy

A molar pregnancy (hydatidiform mole) is a mass of tissue that grows in the uterus after conception. The mass is created by an egg that was not fertilized correctly and abnormally grows. It is an abnormal pregnancy and does not develop into a fetus. If suspected by your caregiver, treatment is required.


Depending on the type of molar pregnancy, the cause may differ.

  • Complete molar pregnancy. The fertilized egg has all of the father's chromosomes and none of the mother's.

  • Partial molar pregnancy. There is too much genetic information from the father and mother.


Certain risk factors make a molar pregnancy more likely. They include:

  • Becoming pregnant after age 35 or under age 20.

  • History of a molar pregnancy in the past (extremely small chance of recurrence).

Other possible risk factors include:

  • Smoking more than 15 cigarettes per day.

  • History of infertility.

  • Having a certain blood type (A, B, AB).

  • Having a vitamin A deficiency.

  • Using oral contraceptives.


  • Vaginal bleeding.

  • Missed menstrual period.

  • Uterus grows quicker than normal.

  • Severe nausea and vomiting.

  • Severe pressure or pain in the uterus.

  • Abnormal ovarian cysts (theca lutein cysts).

  • Discharge from the vagina that looks like grapes.

  • High blood pressure (early onset of preeclampsia).

  • Overactive thyroid (hyperthyroidism).

  • Anemia.


If your caregiver thinks there is a chance of a molar pregnancy, testing will be recommended. Your caregiver can explain specific tests to you. Possible tests include, but are not limited to:

  • An ultrasound.

  • Blood tests.

After diagnosis of a molar pregnancy, the pregnancy hormone levels must be followed until the level is 0.


Most molar pregnancies end on their own by miscarriage. However, a caregiver needs to make sure that all the abnormal tissue is out of the womb. This can be done with:

  • Dilation and curettage (D&C) or suction curettage. This procedure removes any remaining molar tissue. It is taken out through the vagina.

  • Chemotherapy. If the pregnancy hormone level does not drop appropriately, chemotherapy may be necessary.

  • RhoGAM. This will be necessary if you are Rh negative and your sex partner is Rh positive, to prevent Rh problems with future pregnancies.


  • Avoid getting pregnant for 6 to 12 months or as directed by your caregiver. Use a reliable form of birth control or do not have sex.

  • Take all medicine as directed by your caregiver.

  • Keep all follow-up appointments and perform all suggested lab tests and ultrasounds.

  • Gradually return to normal activities.

  • Think about joining a support group. Ask for help if you are struggling with grief.