What Are the Risk Factors for Gestational Trophoblastic Disease?

A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, mouth, larynx (voice box), bladder, kidney, and several other organs.

But risk factors don't tell us everything. Having a risk factor, or even several risk factors, does not mean that you will get the disease. And some people who get the disease might not have any known risk factors. Even if a person has a risk factor, it is often very hard to know how much that risk factor may have contributed to the cancer.

Researchers have found several risk factors that might increase a woman's chance of developing gestational trophoblastic disease (GTD).

Age

GTD occurs in women of childbearing age. The risk of complete molar pregnancy is highest in women over age 35 and younger than 20. The risk is even higher for women over age 45. Age is less likely to be a factor for partial moles. For choriocarcinoma, risk is lower before age 25, and then increases with age until menopause.

Prior molar pregnancy

Once a woman has had a hydatidiform mole, she has a higher risk of having another one. The overall risk for later pregnancies is about 1% to 2%. This risk is much higher if she has had more than one molar pregnancy.

Prior miscarriage(s)

Women who have lost pregnancies before have a higher risk of GTD. This might be at least in part because in some cases GTD affected the miscarried pregnancy. Overall, the risk of GTD after a miscarriage is still low.

Blood type

Women with blood type A or AB are at slightly higher risk than those with type B or O.

Birth control pills

Women who take birth control pills might be more likely to get GTD when they do become pregnant. The link between the use of birth control pills and GTD is weak, and may be explained by other factors. This risk seems to be higher for women who took the pills longer. But the risk is still so low that it doesn't outweigh the benefit of using the pills.

Family history

Very rarely, several women in the same family have one or more molar pregnancies.

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Last Medical Review: November 21, 2017 Last Revised: November 28, 2017

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