This analysis assesses the relation between a history of migraine and the risk of preeclampsia or gestational hypertension. Cases (172 women with preeclampsia and 254 with gestational hypertension) and controls (505) were primiparae with no history of hypertension before pregnancy. Information on migraine attacks in the year before pregnancy was obtained after delivery. Migraine was reported by 16% of preeclamptic women, 12% of women with gestational hypertension, and 8% of the controls. Adjusted odds ratios (95% confidence interval) of preeclampsia and gestational hypertension were 2.44 (1.42-4.20) and 1.70 (1.02-2.85), respectively. We conclude that women who have a recent history of migraine may be at higher risk of pregnancy-induced hypertension.