AbstractBackgroundRisk factors for preeclampsia are well established, whereas, the triggers associated with timing of preeclampsia onset are not. The aim of this study was to establish whether recent infection or other triggers were associated with timing of preeclampsia onset.MethodsWe used a case‐crossover design with preeclampsia cases serving as their own controls. Women with singleton pregnancies of ≥20 weeks gestation presenting at three hospitals were eligible for inclusion. Exposures to potential triggers were identified via guided questionnaire. Infective episodes included symptoms lasting >24 h. Preeclampsia was defined as hypertension (BP ≥140 mmHg and/or ≥90 mmHg) and proteinuria (protein/creatinine ratio ≥30 mg/mmol). Conditional logistic regression was used to compare the odds of exposure to potential triggers in the case windows (1–7 days preceding diagnosis of preeclampsia) and control windows (8–14 days prior to diagnosis); unadjusted odds ratios (ORs) are reported.ResultsAmong 286 recruited women, 25 (8.7%) reported a new infection in the 7 days prior to preeclampsia onset and 21 (7.3%) in the 8–14 days prior. There was no significant association between onset of infection in the 7 days prior and preeclampsia diagnosis (OR 1.24, 95% CI 0.65, 2.34). Consumption of caffeine (OR 0.51, 95% CI 0.33, 0.77), spicy food (OR 0.49, 95% CI 0.30, 0.81), and alcohol (OR 0.26, 95% CI 0.10, 0.71) were strongly inversely associated with preeclampsia onset.ConclusionRecent infection does not appear to trigger preeclampsia. Decreased consumption of caffeine, spicy food, and alcohol may be prodromal markers. Such behaviours may be early markers of imminent preeclampsia.