Background: Many studies have reported that obstetric complications are risk factors for schizophrenia, but few studies have examined whether complications increase risk for bipolar disorder.
Methods: Bipolar-disorder probands and their adult siblings were diagnosed using DSM-III-R criteria. Obstetrical data from maternal reports were scored, blind to diagnosis, applying published scales that take into account number and severity of complications.
Results: Obstetric complication scores were significantly worse in probands than siblings without mood disorders.
Limitations: Probands had relatively severe symptoms; research using more heterogeneous samples is needed.
Conclusion: Results suggest obstetric complications are etiologically significant in bipolar disorder.