[A case-control study on birth defects of newborns in Tangshan].

A case-control study was conducted on birth defects of newborns using L&R disordent pair-matching in Tangshan between 1983 and 1987. The results showed that upper respiratory tract infection among the newborns' mothers during the first 12 weeks pregnancy and a history of newborns' parents who exposed to harmful environment were the main risks of birth defects. There were no evidences that upper respiratory tract infection among the newborns' mothers after the first 12 weeks' pregnancy and taking medicine during pregnancy had obvious association with birth defects.