Risk factors for gestational trophoblastic disease
A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes gestational trophoblastic disease (GTD) develops in women who don’t have any of the risk factors described below.
Rates of GTD are higher in Asia and lower in North America and Europe. Researchers are trying to find out if diet, economic status or other factors are responsible for this difference.
The following are risk factors for GTD. All of the known risk factors are not modifiable. This means that you can’t change them. Until we learn more about these risk factors, there are no specific ways you can reduce your risk.
Risk factors are generally listed in order from most to least important. But in most cases, it is impossible to rank them with absolute certainty.
Known risk factors
There is convincing evidence that the following factors increase your risk for GTD.
GTD occurs in women of child-bearing age. The risk is higher in women who become pregnant over the age of 40 and those who become pregnant under the age of 20.
Women who have a hydatidiform mole, or molar pregnancy, are at a higher risk of having another one or having another type of GTD. A woman’s risk increases with a history of more than one hydatidiform mole.
Although it is rare, there is a type of GTD that occurs in families (familial). Therefore, a family history of GTD may increase your risk.
The following factors have been linked with GTD, but there is not enough evidence to show they are known risk factors. Further study is needed to clarify the role of these factors for GTD.
Several studies have shown a possible link between using oral contraceptives (birth control pills) and an increased risk of GTD. But recent studies suggest that there is no association or that the association is weak.
Some reproductive factors may increase the risk of GTD. These factors include infertility, a history of miscarriage, not having children, having had many children (5 or more), menarche (first menstrual cycle) after 12 years of age and a light menstrual flow.
Some studies have suggested that women with certain blood types are at increased risk of developing GTD. These are women with type A or AB blood, or women with blood type A who have male partners with blood type O.
Unknown risk factors
It isn’t known whether or not the following factors are linked with GTD. It may be that researchers can’t show a definite link or that studies have had different results. Further study is needed to see if the following are risk factors for GTD:
- vitamin A deficiency
- socio-economic status
Questions to ask your healthcare team
To make the decisions that are right for you, ask your healthcare team questions about risks.