Smoking during pregnancy puts babies at risk of congenital heart disease

Infants born to mothers who smoked while pregnant are at heightened risk of developing congenital heart disease (CHD), a study suggests.

The analysis included seven European birth cohorts, which comprised a total of 232,390 offspring and 2,469 CHD cases (1.1 percent). CHD prevalence was close to 1 percent in most cohorts, with the lowest being 0.4 percent and the highest 1.4 percent.

Mean maternal age was generally similar across the cohorts, all late 20s to early 30s. The same was true for mean body mass index (BMI), although the proportions in different categories varied, with the lowest prevalence of prepregnancy/early‐pregnancy obesity recorded at 5 percent and the highest at 21 percent. There were also differences in maternal smoking and alcohol consumption across the cohorts, with highest prevalence rates being 25–26 percent for smoking and 45–55 percent for alcohol use.

Multivariable logistic regression models showed that the odds of offspring CHD were greater among women who with overweight (odds ratio [OR], 1.15, 95 percent confidence interval [CI], 1.01–1.31) or obesity (OR, 1.12, 95 percent CI, 0.93–1.36) as opposed to normal weight. However, no clear evidence of a linear increase in odds was seen across the whole BMI distribution.

Results for paternal overweight, obesity, and mean BMI were similar to the maternal associations.

Maternal smoking during pregnancy conferred higher odds of offspring CHD (OR, 1.11, 95 percent CI, 0.97–1.25), while paternal smoking did not (OR, 0.96, 95 percent CI, 0.85–1.07). The positive association seen for maternal smoking seemed to be driven by nonsevere CHD cases (OR, 1.22, 95 percent CI, 1.04–1.44).

Offspring CHD showed no associations with maternal moderate/heavy pregnancy alcohol consumption (OR, 1.16, 95 percent CI, 0.52–2.58), as was the case with paternal consumption.