Abstract: ObjectiveTo investigate possible risk factors of perinatal birth defect in Changzhou city and to provide evidence for the control of birth defect.MethodsA hospital based 1:3 matched case control study was carried out in 123 cases with birth defect and 369 controls.The parents of the cases and controls were interviewed with a uniformed question naire.Fifty possible risk factors were investigated.Univariate and multiva riate logistic regression analysis were used with SPSS13.0 software.ResultsAnalysis results showed that early unsafely drugs use(odds ratioOR=11.088),the work with harmful environmental exposure(OR=5.755),pregnancy complication(OR=3.761),prolonged sedentary(OR=3.61),bad nutrition in early pregnancy(OR=3.130),and pregnancy illness(OR=2.030)were closely associated with birth defect.ConclusionAvoiding the occurrence of early pregnancy unsafe drugs use,pregnancy sickness,prolonged sitting,focusing on the overall balance of early pregnancy nutrition in take,avoiding contact with toxic and hazardous compounds can reduce the incidence of birth defect.