The primary hypothesis of this study was that contraceptive methods that prevent exposure to sperm and seminal fluid (condoms, diaphragms, spermicides, withdrawal) are associated with an increased risk of developing preeclampsia during the subsequent pregnancy. A case-control study was conducted comparing the contraceptive and reproductive histories of 110 primiparous women with preeclampsia with 115 pregnant women without preeclampsia, aged 15 to 35 years, who gave birth at North Carolina Memorial Hospital, Chapel Hill, between 1984 and 1987. Controls were frequency matched to cases by age, race, and distance from the hospital. Unconditional logistic regression analysis indicated a 2.37-fold (95% confidence interval, 1.01 to 5.58) increased risk of preeclampsia for users of contraceptives that prevent exposure to sperm. A dose-response gradient was observed, with increasing risk of preeclampsia for those with fewer episodes of sperm exposure. These results were supportive of the hypothesis that birth control methods that prevent sperm exposure may play a role in the etiology of preeclampsia.