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Molar Pregnancy

Condition Basics

What is a molar pregnancy?

A molar pregnancy means that tissue that normally becomes a fetus instead becomes a mass of abnormal tissue in your uterus. It is also called a hydatidiform mole. This abnormal tissue causes symptoms of pregnancy.

This tissue can cause serious problems in some cases. So a molar pregnancy should be treated to remove all of the abnormal tissue from your uterus.

What causes it?

Molar pregnancy is thought to be caused by a problem with the genetic information of an egg or sperm. There are two types of molar pregnancy: complete and partial.

  • Complete molar pregnancy. An egg with no genetic information is fertilized by a sperm. It does not develop into a fetus. It continues to grow as a lump of abnormal tissue that looks a bit like a cluster of grapes and can fill the uterus.
  • Partial molar pregnancy. An egg is fertilized by two sperm. The placenta develops into abnormal tissue. Any fetal tissue that forms is likely to have severe defects.

Sometimes a pregnancy that seems to be twins is found to be one fetus and one molar pregnancy. But this is very rare.

Things that may increase your risk of having a molar pregnancy include:

  • Age. The risk for complete molar pregnancy is higher if you are 15 or younger or 35 or older.
  • A history of molar pregnancy, especially if you've had two or more.
  • A history of miscarriage.
  • A diet low in carotene. Carotene is a form of vitamin A.

What are the symptoms?

A molar pregnancy causes the same early symptoms that a normal pregnancy does, such as a missed period or morning sickness. But a molar pregnancy usually causes other symptoms too. These may include:

  • Bleeding from the vagina.
  • A uterus that is larger than normal.
  • Severe nausea and vomiting.
  • Signs of hyperthyroidism. These include feeling nervous or tired, having a fast or irregular heartbeat, and sweating a lot.
  • An uncomfortable feeling in the pelvis.

Most of these symptoms can also occur with a normal pregnancy, a multiple pregnancy, or a miscarriage.

How is it diagnosed?

Your doctor can find a molar pregnancy with:

  • A blood test to measure your pregnancy hormones.
  • A pelvic ultrasound.

Your doctor may also find a molar pregnancy during a routine ultrasound in early pregnancy. Partial molar pregnancies are often found when checking for a miscarriage.

How is a molar pregnancy treated?

When you have a molar pregnancy, you need treatment to remove all of the abnormal tissue from your uterus. The tissue is removed with a procedure called vacuum aspiration.

If you don't want a future pregnancy, you may decide to have your uterus removed (hysterectomy) instead of having a vacuum aspiration to treat your molar pregnancy.

After treatment, you will have regular blood tests to check for gestational trophoblastic neoplasia. This is a form of cancer that can sometimes develop from the abnormal molar tissue. These blood tests may be done over the next 6 to 12 months. If you still have your uterus, you will need to use birth control during this time so you don't get pregnant. It's very important to see your doctor for all follow-up visits.

If trophoblastic neoplasia develops, it is usually found early and can be cured with chemotherapy. In rare cases, the cancer may spread to other parts of the body and more chemotherapy and sometimes radiation treatment is needed.

If you've had a molar pregnancy or trophoblastic neoplasia, it's likely you'll be able to get pregnant later.

After a molar pregnancy, you may feel many different emotions. It may help to find a local support group or talk to your friends, a counselor, or a spiritual advisor.

How can you care for yourself?

  • Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine.
  • You may have vaginal bleeding that's similar to a period. It may last for about 1 to 2 weeks. Use sanitary pads until you stop bleeding. Using pads makes it easier to keep track of your bleeding. You may use tampons during your next period. It should start in 3 to 6 weeks.
  • Ask your doctor when it is okay for you to have vaginal sex.
  • Take an over-the-counter pain medicine, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve), to relieve pain or cramping. Read and follow all instructions on the label. Do not take two or more pain medicines at the same time unless the doctor told you to. Many pain medicines have acetaminophen, which is Tylenol. Too much acetaminophen (Tylenol) can be harmful.
  • Get plenty of rest. You may be more tired than normal for a few weeks.
  • Take it easy. Do not exercise too much or lift heavy objects (more than 20 pounds) until your doctor tells you it is safe to do your normal activities.
  • Pay attention to your feelings. You may have a range of emotions. If you need help coping, talking to a friend, a family member, a counselor, or your doctor may help.
  • Talk to your doctor if you are worried about having children in the future.
  • Most doctors suggest waiting for 6 to 12 months before trying to get pregnant. Ask your doctor about birth control. Without birth control, you might get pregnant before your next period starts.


Current as of: July 10, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.


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