Molar pregnancy information and support

A molar pregnancy is when a fetus doesn’t form properly in the womb. It is a very rare complication of pregnancy.

A molar pregnancy can be a traumatic experience. Try to remember that molar pregnancies are not caused by anything you (or the baby’s father) did or didn’t do. There is support available if you need it.

“Two of the most important things are to not blame yourselves and not to give up hope. Talk about your feelings and emotions with your partner and try to contact others in your local area who have experienced what you are going through. You are never alone.”

Sue

There are two main types of molar pregnancy. Sadly, neither type of pregnancy can survive.

Complete mole

Complete moles usually happen when a single sperm fertilises an ‘empty’ egg which has none of the mother’s genetic material inside. Because of this, a fetus does not develop.

Partial mole

Partial moles happen when two sperm fertilise a normal egg. In a partial mole, there are usually some early signs of a fetus, but this won’t develop into a baby.

What causes a molar pregnancy?

We don’t know exactly what causes a molar pregnancy, but there are some things that increase the risk. Again, try to remember that molar pregnancies are not caused by anything you (or the baby’s father) did or didn’t do.

Age 

Molar pregnancies are more common in teenage women and women over 45.

Ethnicity

Molar pregnancies are about twice as common in women of Asian origin.

Previous molar pregnancy 

If you've had a molar pregnancy before, your chance of having another one is about 1 in 80, compared with 1 in 600 for women who haven't had one before. If you've had 2 or more molar pregnancies, your risk of having another is around 1 in 5.

A low intake of carotene (a form of vitamin A) and folic acid

Women who don't get enough of these vitamins have a higher rate of complete molar pregnancy.

However, you should not take any supplements that include vitamin A. Having large amounts of vitamin A can harm your unborn baby. The best thing you can do to make sure you are getting all the vitamins and minerals you need is to eat a healthy, balanced diet. Find out more about tips for a pre-pregnancy diet.

Folic acid is a vitamin (B9). It is found in certain foods and it can also be taken as tablets. The best thing to do is take folic acid tablets for two to three months before you get pregnant and for the first 12 weeks of pregnancy. This gives the most protection to your future baby against neural tube defects, such as spina bifida.

Find out more about folic acid in pregnancy.

What are the symptoms of a molar pregnancy?

There are often no symptoms of a molar pregnancy. It may only be diagnosed during a routine ultrasound scan at 8-14 weeks or during tests are done after a miscarriage.

Some women with a molar pregnancy have:

Some of these symptoms are quite common in pregnancy and aren't necessarily a sign that anything is wrong with your baby. Try not worry, but contact a health professional and get checked out just in case.

Less common symptoms include:

  • high blood pressure
  • symptoms of an overactive thyroid gland (such as tiredness, weakness, twitching or trembling)
  • stomach pain (because of large ovarian cysts).

When should I get help?

Contact your midwife or GP if you think you have any of these symptoms.

You will be referred to an early pregnancy unit for an ultrasound scan. If you’ve had a molar pregnancy before and you think you are having another, you can contact the early pregnancy unit yourself without contacting your midwife first.

As well as a scan, you will also have a blood test, which measures the amount of a pregnancy hormone called human chorionic gonadotrophin (hCG). This is usually much higher in molar pregnancies than in healthy pregnancies.

Doctors may also discover a molar pregnancy after a woman has a miscarriage if the tissues are looked at under a microscope.

What is the treatment for a molar pregnancy?

Unfortunately, a molar pregnancy will not survive and will need to be removed. You will likely need surgery to remove the pregnancy. Most women are successfully treated with suction removal and can go home later the same day.

What follow-up will I have?

In the UK, all women who have had a molar pregnancy are asked if their details can be registered with a specialist centre. This is so your treatment is provided by doctors who are experts in this field. These centres are in hospitals in London, Sheffield and Dundee.

After registering with a specialist centre, you will have follow-up appointments for at least 6 months. Your specialist centre will ask you to have regular blood or urine tests done at your local GP surgery. These are done to check if your hCG levels are going back to normal.

Does a molar pregnancy have any complications?

Very rarely, a molar pregnancy can lead to gestational trophoblastic neoplasia (GTN). GTN is a rare form of cancer. This sounds frightening, but it has a cure rate of over 99%.

GTN happens when some of the molar pregnancy tissue is still in the uterus. It is usually diagnosed if your hCG levels do not return to normal or if you have persistent or irregular bleeding after a pregnancy.

What happens if I have GTN?

You will usually need to have further treatment from the specialist centre you are registered with. This may involve a second operation to remove any tissue from your womb or chemotherapy.

Treatment is continued until 6 weeks after your hCG level has returned to normal. In very rare cases, some women may need to have a hysterectomy (removal of the womb).

If you have chemotherapy for GTN, your periods will usually restart 2 to 6 months after the end of chemotherapy. Your fertility (ability to get pregnant) is usually not affected.

Your specialist centre will talk to you about the treatment you need and any side effects.

Will I still be able to have a baby in the future?

Yes, you have every chance of getting pregnant again and having a healthy baby. The risk of having another molar pregnancy is small (about 1 in 80).

It’s best not to try getting pregnant again until all your follow-up treatment has finished. For most women, this will take about 6 months.

If you have GTN, you will need to wait for 12 months after you have finished chemotherapy treatment. This is because GTN can sometimes come back. This is rare and happens to around 3% of women.

Contraception

You should use barrier methods of contraception such as condoms or diaphragm until your hCG levels are normal. You should not have an intrauterine contraceptive device fitted until your hCG levels have returned to normal. This is because it can cause a puncture in the uterus after a molar pregnancy.

Once your hCG levels are normal, you may use all types of hormonal contraception including the combined contraceptive pill, progestogen only pill, progestogen injection and progestogen implant.

Talk to your healthcare team about what contraception will be best for you.

How you may feel about a molar pregnancy

It can take time to recover emotionally and physically from a molar pregnancy. Waiting to find out if everything is okay after a lot of tests can be very stressful.

Try to remember that most women who have had a molar pregnancy go on to have healthy pregnancies and babies in the future.

You may find it helpful to:

Royal College of Obstetricians and Gynaecologists (2011) Gestational trophoblastic disease https://www.rcog.org.uk/globalassets/documents/patients/patient-information-leaflets/pregnancy/pi-gestational-trophoblastic-disease.pdf

NHS Choices. Molar pregnancy https://www.nhs.uk/conditions/molar-pregnancy/ (Page last reviewed: 20/07/2017 Next review due: 20/07/2020)

Government of B.C (2017) Molar pregnancy https://www.healthlinkbc.ca/health-topics/hw165877 

NHS Choices. Vitamin A NHS Choices. Molar pregnancy https://www.nhs.uk/conditions/molar-pregnancy/ (Page last reviewed: 20/07/2017 Next review due: 20/07/2020) (Page last reviewed: 03/03/2017 Next review due: 03/03/2020)

NHS Choices Why do I need folic acid in pregnancy? https://www.nhs.uk/chq/pages/913.aspx?categoryid=54 (Page last reviewed: 16/03/2016 Next review due: 16/03/2018)

Review dates

Last reviewed: 5 February 2020
Next review: 5 February 2023