Association between prepregnancy body mass index and congenital heart defects.

OBJECTIVE The purpose of this study was to examine associations between prepregnancy body mass index (BMI) and congenital heart defects (CHDs). STUDY DESIGN These analyses included case infants with CHDs (n = 6440) and liveborn control infants without birth defects (n = 5673) enrolled in the National Birth Defects Prevention Study (1997-2004). RESULTS Adjusted odds ratios for all CHDs combined were 1.16 (95% confidence interval [CI], 1.05-1.29), 1.15 (95% CI, 1.00-1.32), and 1.31 (95% CI, 1.11-1.56) for overweight status, moderate obesity, and severe obesity, respectively. Phenotypes associated with elevated BMI (> or =25.0 kg/m(2)) were conotruncal defects (tetralogy of Fallot), total anomalous pulmonary venous return, hypoplastic left heart syndrome, right ventricular outflow tract (RVOT) defects (pulmonary valve stenosis), and septal defects (secundum atrial septal defect). CONCLUSION These results corroborated those of previous studies and suggested new associations between obesity and conotruncal defects and RVOT defects.