Occurrence of congenital heart defects in relation to maternal multivitamin use

The purpose of this study was to assess the relation between maternal multi vitamin use and risk for cardiac defects in the offspring, using a populati on-based approach. The Atlanta Birth Defects Case-Control study is a popula tion-based case-control study of infants born between 1968 and 1980 to moth ers residing in metropolitan Atlanta, Georgia. The 958 case infants with no nsyndromic cardiac defects were actively ascertained from multiple sources. The 3,029 infants without birth defects (control infants) were selected fr om birth certificates by stratified random sampling. Periconceptional multi vitamin use, defined as reported regular use of multivitamins from 3 months before pregnancy through the first 3 months of pregnancy, was contrasted w ith no use during the same time period. Periconceptional multivitamin use w as associated with a reduced risk for nonsyndromic cardiac defects in the o ffspring (odds ratio (OR) = 0.76; 95% confidence interval (CI): 0.60, 0.97) . The risk reduction was strongest for outflow tract defects (OR = 0.46; 95 % CI: 0.24, 0.86) and ventricular septal defects (OR = 0.61; 95% CI: 0.38, 0.99). No risk reduction was evident when multivitamin use was begun after the first month of pregnancy. If these associations are causal, the results suggest that approximately one in four major cardiac defects could be prev ented by periconceptional multivitamin use.