Guangdong Cardiovascular Institute Provincial People’s Hospital Academy of Medical Sciences 510100;
Department of Epidemiology and Health Statistics School of Public Health South University 410078;
NHC Key Laboratory of Birth Defect for Research and Prevention Provincial Maternal and Child Health Care Hospital 410008;
Hunan Children's Hospital 410007;
Congenital heart defect; Maternal drug use; Cytochrome P450 genes; Case-control study;