Preeclampsia is a major complication of pregnancy and a predictor of future chronic disease. We investigated the hypothesis that a woman's own weight and gestational age as a newborn influence her risk of developing preeclampsia later in life. This case-control study used linked computerized birth registry data from the Colorado Department of Public Health and Environment. The study subjects were women ages 12-20 who were born in Colorado after 1974, each of whom delivered a live infant in Colorado between 1990 and 1995. Cases were subjects with a report of eclampsia and/or preeclampsia on the 1990-1995 birth records (N = 345). Controls were randomly selected from subjects with uncomplicated pregnancies who were frequency matched to cases by year of delivery (N = 3,995). Records from each subject's pregnancy (1990-1995) were then linked to those from her own birth (1975-1983). Birth weight and gestational age, as recorded on the subject's birth records, were independently associated with the risk of developing preeclampsia after adjustment for age, parity, race/ethnicity, and other risk factors. The risk of preeclampsia decreased with increasing gestational age in a dose-dependent fashion; relative to mothers born post-term, adjusted odds ratios for preeclampsia ranged from 3.62 [95% confidence interval (95% CI) = 1.27-10.28] for mothers born at less than 34 weeks gestational age to 1.45 (95% CI = 0.85-2.45) for those born at term. Relative to women who were born at 8.5 lb or more, those born in the lowest weight category (under 4.5 lb) appeared at greatest risk for preeclampsia (odds ratio = 5.16; 95% CI = 1.24-21.51), although no directional trend was apparent. These findings suggest that women born small or premature may be at increased risk of developing preeclampsia as teenagers or young adults.