Relationship of obstetric complications and differences in size of brain structures in monozygotic twin pairs discordant for schizophrenia

Objective: The aim of the study was to determine whether a history of obste tric complications and congenital minor physical anomalies are related to d ifferences in the characteristics of brain structures observed within monoz ygotic twin pairs discordant for schizophrenia. Method: The size of the bil ateral hippocampi and cerebral ventricles was studied by magnetic resonance imaging in 22 monozygotic twin pairs discordant for schizophrenia. Obstetr ic complications and minor physical anomalies were independently assessed t hrough parental report and examination, respectively. Results: Compared wit h the well co-twins, the ill twins consistently had smaller left and right hippocampi as well as larger left lateral ventricles and third ventricles, Relatively small left and right hippocampi were each significantly related to labor-delivery complications and to prolonged labor per se. Relatively l arge right lateral ventricle size and large total ventricle size were signi ficantly related to labor-delivery complications, prolonged labor, neonatal complications, and total complications for the entire reproductive sequenc e. In contrast, these brain size differences were not significantly associa ted with pregnancy complications or minor physical anomalies. Conclusions: Trauma at the time of labor and delivery and especially prolonged labor app ear to be of importance for brain structure anomalies associated with schiz ophrenia.