Obstetric complications and schizophrenia. Two case-control studies based on structured obstetric records.

BACKGROUND: Most previous case-control studies of obstetric complications in schizophrenia have been small scale and many have relied on retrospective information. AIMS: To determine which obstetric complications are more common in probands with schizophrenia than matched controls. METHOD: Two hundred and ninety-six probands with an in-patient diagnosis of schizophrenia who had been born in Scotland in 1971-74, and a further 156 born in 1975-78, were closely matched with controls and the incidence of obstetric complications in the two compared using obstetric data recorded in a set format shortly after birth. RESULTS: Not a single complication of pregnancy or delivery was significantly more common in the probands with schizophrenia than the controls in the 1971-74 birth cohort and only emergency Caesarean section and labour lasting over 12 hours were significantly more common in the schizophrenia probands in the 1975-78 cohort. CONCLUSION: The evidence that schizophrenia is associated with a raised incidence of obstetric complications is weaker than has recently been assumed.