Synergistic Effect of Maternal Smoking and Obesity on Birth Defects

Smoking has long been known to adversely affect pregnancy outcomes; more recently, adverse effects of obesity have also been shown (JW Womens Health Mar 23 2004 and Pregnancy Hypertens 2011; 1:6). In a case-control study, Dutch investigators used a population-based birth defects registry to examine the interaction of these two risk factors in 797 infants and fetuses born between 1997 and 2008 with isolated nonsyndromic congenital heart anomalies; controls were 322 infants and fetuses from the registry with other chromosomal anomalies but no cardiac defects. Nineteen case mothers were both smokers and obese (based on prepregnancy weight).

In analyses adjusted for maternal age, education, folic acid use, and periconceptional alcohol consumptio…