Although doctors cannot always explain why a woman developed GTD, the following factors may increase the risk of developing this disease:
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Age
Because a woman's egg must be fertilized with sperm before GTD can occur, women of childbearing age are at greater risk than women who have reached menopause and are no longer producing eggs. The risk of GTD, although always low, is highest in women who become pregnant younger than age 20 or over the age of 40. Very rarely does GTD occur in prepubescent girls or postmenopausal women.
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Prior GTD
Women who have had one hydatidiform mole or choriocarcinoma are at increased risk of having another.
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First Pregnancies
Women who have not had children previously may be more likely to develop GTD than those who have had several children.
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Blood Type
For unexplained reasons, women with blood types B or AB have a slightly higher risk of GTD than those with types A or O. However, this risk factor is not as strong as age and past history of GTD.
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Diet
There is some evidence that indicates that women whose diets are low in beta carotene or vitamin A may have a slightly higher risk of developing GTD.
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Use of Oral Contraceptives
Women taking birth control pills are 50 percent more likely to develop GTD when pregnancy occurs. Though the vast majority of women using oral contraceptives do not develop GTD, the risk is higher for women using oral contraceptives for a longer period of time.
