ObjectivesTo Investigate the occurrence of birth defects and relevant factors in fetuses and infants of Changsha city during their perinatal period , taking aim at providing basis for improvement of intervention measures.MethodsMonitoring analysis of the birth defects in 25 713 fetuses and infants during perinatal period was carried out . They were born in obstetric wards of 13 hospitals in Changsha city from Jan., 2000 to Dec., 2001. At the time of this screening survey, majority of them were just de...