Calcium intake from dairy products and supplements and the risks of preeclampsia and gestational hypertension.

This case-control study assessed the relation of calcium intake in the first 20 weeks of pregnancy to the risks of preeclampsia and gestational hypertension. All subjects (172 women with preeclampsia, 251 women with gestational hypertension, and 505 controls) were primiparae who delivered in Quebec City or Montreal, Quebec, Canada, between April 1984 and December 1986. Dietary calcium intake was not associated with preeclampsia. For gestational hypertension, adjusted odds ratios in successive quartiles gradually decreased from 1.00 in the lowest quartile to 0.81, 0.66, and 0.60 in the highest quartile. These results provide additional support for the view that calcium intake during pregnancy may be inversely related to the risk of gestational hypertension.