Schizophrenia, influenza and obstetric complications

Objective: An association between prenatal exposure to influenza and adult schizophrenia was reported in the literature. We studied this association and the relationship of obstetric complications, another risk factor, in patients with schizophrenia. Method: We assessed infections during pregnancy, obstetric complications, gestational age and birth weight by interviewing the mothers of 35 patients with DSM-4 schizophrenia, using a structured interview. Results: Significantly more infections were not reported in the second trimester of the patients' gestations than in the combined first and third trimesters. Influenza accounted for 50% of second-trimester infections. No influenza was reported in the combined first and third trimesters. Patients with schizophrenia whose mothers reported having influenza during the second trimester were not more likely to experience at least one definite obstetric complication than were patients who were not exposed to influenza during the second trimester. The exposed patients weighed a mean of 250 g. less at birth than the unexposed patients. Conclusions: Maternal influenza during the second trimester as well as other infections in all three trimesters may impair fetal growth and predispose to obstetric complications and lower birth weight in a proportion of individuals destined to develop schizophrenia.