Intra-uterine physical growth in schizophrenia: evidence confirming excessof premature birth

Background. Many studies have suggested a possible aetiological role for ob stetric complications in the development of schizophrenia. We focused on pr enatal physical growth in schizophrenia, a contentious issue in the literat ure. Methods. We compared gestational age at birth, birth weight (BW) and birth head circumference (BHC) between 312 schizophrenics and 517 controls, and b etween 187 schizophrenics and their matched healthy siblings, Information o n obstetric histories was obtained from the Maternal and Child Health Handb ooks (i.e. contemporaneous records). Results. Gestational age at birth was significantly earlier in the schizoph renics than in the controls (P = 0017). Pre-term birth (gestational age of 36 weeks or less) was more common in schizophrenics than in controls (8.0% v. 3.4%, P = 0.005, odds ratio 2.5). Low BW (2500 g or less) was more frequ ent in schizophrenics than in controls (9.6% v. 4.6%, P = 0.005, odds ratio 2.2). The schizophrenics had significantly lighter BW (P = 0.0003) and ten ded to have smaller BHC (P = 0.081) compared with controls. However, multip le regression analysis showed that there was no significant difference in B W or BHC between the schizophrenics and controls when gestational age and m aternal weight were controlled. There was no significant difference in BW o r BHC between schizophrenics and their siblings, although the schizophrenic s tended to be born at earlier gestational age than their siblings. Conclusions. Our results suggest that prematurity at birth is associated wi th a risk of developing schizophrenia in adulthood. When gestational age an d maternal body weight were allowed for, there was no evidence that schizop hrenics tend to have lower mean BW or smaller BHC.