Risk factors for complete molar pregnancy from a case-control study.

Demographic, reproductive, and dietary histories for 90 white women with complete molar pregnancy were compared in a multivariate analysis with those of 90 parous controls matched to cases by residence, birth year, and race. Women with molar pregnancy were more likely to have been born outside North America (relative risk = 1.9, p = 0.05), were more likely to have been past age 30 at time of their molar pregnancy (relative risk = 1.6, p = 0.05), and were more likely to have diets deficient in the vitamin A precursor carotene. Women with dietary scores for carotene above the control median had a relative risk for molar pregnancy of 0.6 (p = 0.02). In addition, there was a significant trend for decreasing risk for molar pregnancy with increasing consumption of carotene. Although other nutritional deficiencies in patients with complete molar pregnancy may exist, carotene is a biologically plausible candidate for a nutritional risk factor that could explain the geographic distribution of molar pregnancy.