Children born to mothers who smoked during pregnancy are at an increased risk of having congenital heart disease (CHD), an international multicohort study led by the University of Bristol has found.
The study, published in the Journal of the American Heart Association, included data on 232,390 offspring (2469 CHD cases; 1.1%) from seven European birth cohorts from the UK, Ireland, the Netherlands, Denmark, Norway and Italy including the Children of the 90s study at the University of Bristol.
The researchers applied negative exposure paternal control analyses to explore the intrauterine effects of maternal body mass index (BMI), smoking and alcohol consumption during pregnancy on offspring CHDs and CHD severity. They used logistic regression, adjusting for confounders and the other parent's exposure and combined estimates using a fixed-effects meta-analysis.
In adjusted analyses, maternal overweight (OR, 1.15; 95% CI, 1.01-1.31) and obesity (OR, 1.12; 95% CI, 0.93-1.36), compared with normal weight, were associated with higher odds of CHD, but there was no clear evidence of a linear increase in odds across the whole BMI distribution.
Associations of paternal overweight, obesity and mean BMI were similar to the maternal associations.
Maternal pregnancy smoking was associated with higher odds of CHD (OR, 1.11; 95% CI, 0.97-1.25), but paternal smoking was not (OR, 0.96; 95% CI, 0.85-1.07).
The positive association with maternal smoking appeared to be driven by non-severe CHD cases (OR, 1.22; 95% CI, 1.04-1.44), the study authors said.
Associations with maternal moderate/heavy pregnancy alcohol consumption were imprecisely estimated (OR, 1.16; 95% CI, 0.52-2.58) and similar to those for paternal consumption.
Lead author Kurt Taylor, a PhD student at the University of Bristol, said: “These results might help in supporting women of reproductive age not to start smoking. Meanwhile it continues to be appropriate to recommend that women, and men, maintain a healthy weight and limit alcohol consumption prior to and during pregnancy."
