When Dad Smokes During Pregnancy, Heart Defects Are a Bigger Risk

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Secondhand smoke from fathers-to-be raises a baby’s risk of congenital heart defects by up to 124 percent. New research finds that secondhand smoke from dad is even more dangerous to a developing baby than when mom smokes during pregnancy.

The research, published in the European Journal of Preventive Cardiology, is the first effort to analyze the effects of paternal smoking, maternal secondhand smoke exposure, and congenital heart defect risk. Chinese researchers compiled data from 125 studies involving more than 137,000 babies with congenital heart defects and nearly 9 million prospective parents.

Whether by mom or dad, smoking during pregnancy was associated in the study with a higher risk for fetal heart defects. Paternal smoking resulted in a 74 percent higher risk, maternal passive smoking, as secondhand smoking is called, resulted in a 124 percent higher risk, and maternal smoking in a 25 percent higher risk, compared to risks for babies whose parents didn’t smoke during pregnancy.

Mom’s smoking during pregnancy upped the risk but smoking prior to conceiving did not. However, maternal exposure to secondhand smoke at all stages of pregnancy, as well as prior to conception, raised heart defect risk.

Types of heart defects linked to parental smoking include atrial septal defects and ventricular outflow obstructions. Congenital heart defects are the world’s leading cause of stillbirth, affecting 8 in 1,000 newborns. Although prognosis and quality of life continue to improve with advances in diagnosis and treatment, the effects of these birth defects can be lifelong.