Obstetrical complications in patients with bipolar disorder and their siblings.

Although indirect evidence suggests that obstetric complications are risk factors for bipolar disorder, few studies have directly addressed this question. Probands with bipolar disorder and their adult siblings were diagnosed according to DSM-III-R criteria by clinicians who had no knowledge of the subjects' obstetrical histories. Hospital records on gestations and births of 16 probands and 20 of their siblings without major mood disorders were scored for obstetric complications without knowledge of diagnosis. The assessment of obstetrical history was based on rating scales that have proved reliable and that reflect the number and severity of complications. Overall complication scores were significantly more severe in probands than siblings. Differences were most marked for perinatal complications.