RESUMO
Objective To explore the main risk factors related to birth defects to provide the scientific basis for making the best prevention policy and implementing the effective interventions .Methods Totally 21 domestic research articles on the risk fac‐tors of birth defects were comprehensively analyzed by the meta analysis method ,including accumulated 6 112 patients and 15 741 control cases .The articles were screened preliminarily according to inclusion and exclusion standard ,and then the fixed and random effects model were selected according to the homogeneity test .The merged results were performed the chi‐square test .Results The main merged results OR values of single‐factor‐analysis were as follows:the family history of birth defects 36 .22 ,early pregnant in‐fectious disease 5 .62 ,early pregnancy exposure to chemicals 4 .19 ,paternal smoking 3 .89 ,contact sedatives during pregnancy 3 .19 , pregnancy complication 2 .94 ,high protein food during pregnancy 0 .37 ;the main merged results OR values of multiple‐factor‐analy‐sis were as follows :early pregnancy infectious disease 7 .65 ,poor prenatal mental state 5 .44 ,early pregnancy fever 4 .70 ,early preg‐nancy exposure to toxic chemical 3 .90 ,history of abortion 3 .59 ,supplement of multivitamin during pregnancy 0 .45 .Conclusion The main risk factors of birth defects in our country are family history of birth defects ,early pregnancy infectious disease ,early pregnancy exposure to chemicals ,paternal smoking and pregnancy complication;the protective factors are eating more high protein food during pregnancy ,supplement of multivitamin during pregnancy and taking folic acid during pregnancy .