OBJECTIVE: To examine whether depression and anxiety in early pregnancy are associated with preeclampsia in an unselected nulliparous population. METHODS: In this prospective population-based study during pregnancy at outpatient maternity clinics in the Helsinki metropolitan area, depression was assessed by a Finnish modification of the short form of the Beck Depression Inventory and anxiety by one established question. Preeclampsia was defined as elevated blood pressure (BP) (more than 140/100 mmHg) and proteinuria (0.3 g during 24 hours or more). Age, smoking, alcohol consumption, marital status, socioeconomic status, and bacterial vaginosis were analyzed as potentially confounding factors in a multiple logistic regression analysis. RESULTS: Six hundred twenty-three consecutive nulliparous women with singleton pregnancies were studied at ten to 17 (median 12) weeks' gestation and at delivery. Of them, 28 (4.5%) women developed preeclampsia. Depression (mean Beck score 4.5, range 3-17) was observed in 185 (30%), women and anxiety was observed in 99 (16%) in early pregnancy. In multivariate analysis, after adjustment for potentially confounding factors, depression was associated with increased risk (odds ratio [OR] 2.5; 95% confidence interval [CI] 1.1, 5.4) for preeclampsia, as was anxiety (OR 3.2; 95% CI 1.4, 7.4). Either depression or anxiety, or both, were associated with increased risk (OR 3.1; 95% CI 1.4, 6.9) for preeclampsia. Bacterial vaginosis together with depression was associated with increased risk (OR 5.3; 95% CI 1.8, 15.0) for preeclampsia. CONCLUSION: Depression and anxiety in early pregnancy are associated with risk for subsequent preeclampsia, a risk further increased by bacterial vaginosis.