A molar pregnancy happens when abnormal cells develop in the womb instead of a healthy baby. This is also known as gestational trophoblastic disease.
In the general population, about 1 pregnancy in every 700 will be a molar pregnancy. If you have had a molar pregnancy in the past, you have a 1 in 80 chance of having a second molar pregnancy.
Experiencing a molar pregnancy can be distressing. You and your partner may need extra support.
A molar pregnancy will never result in the birth of a baby. There is nothing that you or your partner could have done to prevent this.
It is not fully understood why molar pregnancies happen.
But, molar pregnancies are more common:
- in teenagers and women in their 40s
- in women from Asia
- if you have had a molar pregnancy in the past
Symptoms and diagnosis
Symptoms may include:
- bleeding from the vagina
- severe morning sickness
- swelling of the lower part of the abdomen
- a larger-than-expected womb in early pregnancy - your GP may notice this when they examine you
All of these symptoms are relatively common in pregnancy and do not always mean something is wrong.
Many molar pregnancies have no symptoms and are picked up during a regular scan.
There are 2 types of molar pregnancy:
- complete molar pregnancy - when there are abnormal cells in the womb and the baby never develops
- partial molar pregnancy - when an abnormal embryo begins to form, but will never develop into a healthy pregnancy
If you are diagnosed with a molar pregnancy you will be advised to have the abnormal tissue removed.
There are two options:
A suction device is used to remove the abnormal tissue from your womb. This is the most common treatment.
During the operation you will be put to sleep, using general anaesthetic.
Sometimes the abnormal tissue from a partial molar pregnancy is too large to be removed by surgery. In this case, you will be given medicine to induce a miscarriage.
Recovery after a molar pregnancy
In a small number of cases, some abnormal cells remain after treatment. These cells usually go away on their own, but not always.
Your hospital will monitor you for at least 6 months through blood or urine tests to see if you need further treatment.
If you have had a molar pregnancy you should be tested after any future birth or miscarriage to make sure there are no abnormal cells in your womb. If abnormal cells are not treated they can become dangerous to your health.
You can begin having sex as soon as you feel physically and emotionally ready. But you should not become pregnant again until your monitoring has finished. This is in case you need any further treatment.
You should use contraception until your obstetrician tells you it is safe to become pregnant again. Check with your obstetrician or GP which kinds of contraception are safe for you to use.
Persistent trophoblastic disease
This is when abnormal cells do not go away after a molar pregnancy. This can be serious, as these cells can behave like cancer cells if left untreated.
Treatment may include:
- an operation to empty your womb
- a type of chemotherapy to kill the abnormal cells - this will not cause sickness or hair loss
- a tablet called folinic acid
Over 99% of women will be completely cured after this type of treatment.