Molar Pregnancy
What is Molar Pregnancy?
A molar pregnancy is a rare complication where abnormal tissue grows inside the uterus instead of a healthy baby. This happens when something goes wrong during fertilization. The cells that should form the placenta develop incorrectly and create a mass of fluid filled cysts.
There are two types of molar pregnancy. A complete molar pregnancy has no normal placenta or fetal tissue at all. A partial molar pregnancy may have some normal placental tissue mixed with the abnormal growth. Both types produce very high levels of a pregnancy hormone called human chorionic gonadotropin or hCG. This condition affects about 1 in 1,000 pregnancies in the United States.
Molar pregnancies cannot result in a viable baby and must be removed. Most cases are detected early through blood tests and ultrasound. With proper treatment and monitoring, women can go on to have healthy pregnancies in the future. Early detection and treatment prevent serious complications.
Symptoms
- Vaginal bleeding, often dark brown or bright red, during the first trimester
- Severe nausea and vomiting, worse than typical morning sickness
- Uterus that grows larger than expected for the pregnancy date
- High blood pressure early in pregnancy
- Passage of grape like tissue clusters from the vagina
- Pelvic pain or pressure
- Signs of hyperthyroidism, including rapid heartbeat and tremors
- Anemia or extreme fatigue
Some women have no symptoms early on and only discover the condition during a routine ultrasound. Others may notice unusually severe pregnancy symptoms because of the extremely high hCG levels.
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Causes and risk factors
Molar pregnancy occurs when fertilization goes wrong at the cellular level. In a complete molar pregnancy, an egg with no genetic material is fertilized by one or two sperm. The resulting cells multiply abnormally without forming a baby. In a partial molar pregnancy, two sperm fertilize one normal egg, creating too many chromosomes. This leads to abnormal growth with some fetal tissue present.
Certain factors increase your risk of molar pregnancy. Women under age 20 or over age 35 face higher risk. Previous molar pregnancy raises your chance of another one to about 1 in 100. A history of miscarriage also increases risk. Some studies suggest dietary factors, particularly low intake of protein and certain vitamins, may play a role. Asian women appear to have slightly higher rates, though researchers are still studying why.
How it's diagnosed
Doctors diagnose molar pregnancy through a combination of blood tests and ultrasound. Very high hCG levels, often much higher than expected for the pregnancy stage, are a key warning sign. An ultrasound typically shows a characteristic snowstorm or cluster of grapes pattern instead of a developing fetus. These two findings together usually confirm the diagnosis.
Rite Aid offers hCG testing through our lab network at Quest Diagnostics. You can add hCG testing to your wellness panel to monitor hormone levels. After diagnosis and treatment, your doctor will order regular hCG tests to make sure your levels drop to zero. This monitoring continues for 6 to 12 months to catch any remaining abnormal tissue early.
Treatment options
- Surgical removal of abnormal tissue through dilation and curettage, a procedure that empties the uterus
- Regular hCG blood tests after treatment to monitor for any remaining tissue
- Avoiding pregnancy for 6 to 12 months while hCG levels are monitored
- Using reliable birth control during the monitoring period
- Chemotherapy in rare cases where tissue continues growing or spreads
- Treatment of symptoms like anemia or thyroid issues as needed
- Emotional support and counseling to process pregnancy loss
- Follow up appointments every 2 to 4 weeks until hCG reaches zero
Need testing for Molar Pregnancy? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
No, a molar pregnancy cannot develop into a healthy baby. The abnormal tissue must be removed completely. After treatment and monitoring, most women can have successful pregnancies in the future. Your doctor will guide you on when it is safe to try again.
Most women see their hCG levels drop to zero within 8 to 12 weeks after treatment. Your doctor will test your blood regularly during this time. If levels stay high or rise again, you may need additional treatment. Complete monitoring usually continues for 6 to 12 months.
Remaining tissue can continue to grow and may spread to other parts of the body. This is called persistent gestational trophoblastic disease. It happens in about 15 to 20 percent of complete molar pregnancies. Regular hCG monitoring catches this early so it can be treated with chemotherapy.
Most women who have had a molar pregnancy go on to have healthy babies. Your fertility is usually not affected. However, you do have a slightly higher chance of another molar pregnancy, about 1 to 2 percent. Your doctor will monitor future pregnancies more closely with early ultrasounds and hCG tests.
The abnormal tissue in a molar pregnancy produces much more hCG than a normal pregnancy. These cells multiply rapidly and make excessive amounts of this hormone. Levels can be 10 times higher than expected. This is why the blood test is such a useful diagnostic tool.
No, these are different conditions. An ectopic pregnancy happens when a fertilized egg implants outside the uterus, usually in a fallopian tube. A molar pregnancy grows inside the uterus but involves abnormal tissue instead of a healthy embryo. Both require medical treatment but in different ways.
The extremely high hCG levels trigger severe nausea and vomiting. This hormone affects the part of your brain that controls nausea. Many women with molar pregnancy experience hyperemesis gravidarum, which is much worse than typical morning sickness. Symptoms usually improve after the tissue is removed and hCG levels drop.
Yes, you should work with an obstetrician or gynecologist who has experience with this condition. Some women may also see a gynecologic oncologist, a doctor who specializes in reproductive system cancers and related conditions. These specialists ensure proper treatment and long term monitoring.
Doctors strongly recommend waiting until your hCG levels have been zero for at least 6 months. Getting pregnant during monitoring makes it impossible to tell if rising hCG is from a new pregnancy or remaining abnormal tissue. This delay helps ensure any persistent disease is caught and treated.
While no diet prevents molar pregnancy completely, good nutrition may help reduce risk. Eat adequate protein and foods rich in folate and vitamin A. Include leafy greens, lean meats, eggs, and orange vegetables in your diet. Talk to your doctor about prenatal vitamins if you are planning pregnancy.