Abstract
To examine the relations between age at menarche and menstrual cycle characteristics and preeclampsia risk, we analyzed data from a case-control study conducted from 1998 to 2002. Usual menstrual cycle characteristics among 286 preeclampsia cases and 471 normotensive controls were assessed using a structured interview during postpartum hospitalization. We used multivariable logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), adjusting for confounders. We also examined the influence of pre-pregnancy body mass index (BMI) on selected hypothesized relations. Among lean women (pre-pregnancy BMI < 25 kg/m2), preeclampsia risk was lower in those reporting cycles ⩾36 days in length (adjusted OR 0.78, CI 0.35–1.83) and menarche at ⩾14 years (adjusted OR 0.48, 95% CI 0.28–0.82). In contrast, among overweight or obese women, preeclampsia risk was higher in those with long cycles (OR 3.11, 95% CI 0.62–1.56, pinteraction = 0.16) and late menarche (OR 1.53, 95% CI 0.59–3.97, pinteraction = 0.03). These data suggest that adiposity influences the relations between usual menstrual cycle length, age at menarche, and preeclampsia. Overweight women with long cycles are at particularly high preeclampsia risk.