Obstetric complications as risk factors for schizophrenia spectrum psychoses in offspring of mothers with psychotic disorder.

BACKGROUND Obstetric complications have predicted future development of schizophrenia in previous studies, but they are also more common in mothers with schizophrenia. The aims of this study were to compare the occurrence of obstetric complications in children of mothers with schizophrenia spectrum psychoses and control children, and to investigate whether obstetric complications predicted children's psychiatric morbidity. METHOD The Helsinki High-Risk (HR) Study monitors females born between 1916 and 1948 and treated for schizophrenia spectrum disorders in Helsinki psychiatric hospitals, their offspring born between 1941 and 1977, and controls. We examined information on obstetric complications and neonatal health of 271 HR and 242 control offspring. We compared the frequency of obstetric complications and neonatal health problems in the HR group vs controls and in HR children who later developed psychotic disorders vs healthy HR children. A Cox regression model was used to assess whether problems in pregnancy or delivery predicted psychiatric morbidity within the HR group. RESULTS Few differences between HR and control offspring were found in obstetric complications. Within the HR group, infections (hazard rate ratio [HRR] 3.73, 95% CI 1.27-11.01), hypertension during pregnancy (HRR 4.10, 95% CI 1.15-14.58), and placental abnormalities (HRR 4.09, 95% CI 1.59-10.49) were associated with elevated risk of schizophrenia spectrum psychoses. CONCLUSIONS Common medical problems during pregnancy were associated with increased risk of schizophrenia spectrum psychoses in offspring of mothers with schizophrenia spectrum psychoses. These results underline the role of the prenatal period in the development of schizophrenia and the importance of careful monitoring of pregnancies of mothers with psychotic disorder.