Women with schizophrenia: pregnancy outcome and infant death among their offspring

Schizophrenia in the mother may imply an increased risk of adverse pregnancy outcome. However, inconclusive findings, unknown pathological mechanisms and possible confounding by social factors and smoking requests further explorations. The aim of this study were to (1) examine non-optimal pregnancy outcome using data from a population-based cohort, controlling for covariates known to influence fetal growth; and (2) perform separate analyses of women diagnosed before childbirth and women hospitalized for schizophrenia during pregnancy. The study sample comprised 2096 births by 1438 mothers diagnosed with schizophrenia (of whom 696 mothers were antenatal diagnosed and 188 admitted during pregnancy) and 1,555,975 births in the general population. We found significantly increased risks for stillbirth, infant death, preterm delivery, low birth weight, and small-for-gestational-age among the offspring of women with schizophrenia. Women with an episode of schizophrenia during pregnancy had the highest risks (e.g., low birth weight; OR 4.3, 95% CI 2.9-6.6 and stillbirth; OR 4.4, 95% CI 1.4-13.8). Controlling for a high incidence of smoking during pregnancy among schizophrenic women (51% vs. 24% in the normal population) and other maternal factors (single motherhood, maternal age, parity, maternal education, mothers' country of birth and pregnancy-induced hypertensive diseases) in a multiple regression model, reduced the risk estimates markedly. However, the risks for adverse pregnancy outcomes were even after adjustments generally doubled for women with an episode of schizophrenia during pregnancy compared to women in the control group (e.g., low birth weight; OR 2.3, 95% CI 1.5-3.5, preterm delivery; OR 2.4, 95% CI 1.5-3.8 and stillbirth; OR 2.5, 95% CI 0.8-7.9). The risks for preterm delivery and low birth weight were significantly elevated throughout the analyses. We conclude that schizophrenia in the mother implies an increased risk for poor perinatal outcome, not fully explained by maternal factors, and a need to consider a common familial (probably genetic) vulnerability for pre- and perinatal stress and schizophrenia.