Risks and causes of molar pregnancy

Molar pregnancies are not cancer (they are benign). There is a very small risk that the molar cells could become cancerous if they are not all removed. 

Read more about molar pregnancy

What is a risk factor?

Anything that can increase your risk of getting a disease is called a risk factor. Different conditions have different risk factors. Having one or more of these risk factors doesn't mean you will definitely get a molar pregnancy.

Risk factors for molar pregnancy

Researchers haven't yet been able to identify what causes molar pregnancies. But we do know of some factors that increase a woman's risk of developing one.

Most women who have one or more risk factors never develop a molar pregnancy. And some people who have none of the risk factors do develop one.

Age

All women who become pregnant have a risk of developing a molar pregnancy but the risk is very small. Researchers have found that some types of molar pregnancy are more common in certain age groups.

Complete molar pregnancies are more common in women over the age of 40. There is a moderate increased risk for young teenagers.

Age doesn't affect the risk of partial molar pregnancies.

Find out about types of molar pregnancy

Ethnicity

There is some evidence that molar pregnancy is higher in Asian women compared to non-Asian women. It isn't yet clear why this is the case.

Previous molar pregnancy

If you've already had one molar pregnancy, you have about a 1 in 100 chance (1%) of having another one. This means that about 99 out of every 100 women (99%) who become pregnant after a molar pregnancy will have a normal pregnancy.

If you have had two or more molar pregnancies your risk of having another is higher, at about 15 to 20 out of 100 (about 15 to 20%).