New study: Babies harmed when pregnant parent is exposed to secondhand smoke

The dangers of smoking during pregnancy are well documented. However, a new study suggests that even low levels of smoke or aerosol may harm a developing baby; and the mother does not have to be a smoker herself for that to happen.

The results provide additional justification for policies that prohibit smoking in workplaces, apartment buildings, vehicles, recreation areas, etc.

The research was part of a larger “Newborn Epigenetic Study” (NEST), which is looking at the effects of prenatal environmental exposures and nutrition on child development. It is being carried out by North Carolina State University and Duke University Medical Center.

This follows research that was conducted with pregnant smokers. When the parent smoked during pregnancy, there were increased risks of a baby being born with an orofacial cleft (defect of lip and/or palate), or having problems with tooth development and eruption, asthma, hepatocellular carcinoma (a form of liver cancer), and colorectal and breast cancers.

In the new study, blood samples were taken from pregnant non-smokers and from umbilical cords at the time of their babies’ births. It was tested for cotinine, a chemical that results from the metabolism of nicotine in the body.

There was a positive correlation between cotinine levels and DNA changes in the blood, referred to as DNA methylation. The changes can affect ways the baby’s genes are expressed, affecting physical development and nervous system functioning. As in the case of pregnant smokers, babies can also be at increased risk of developing cancer later in life.

In general, secondhand smoke has long been known to be harmful. Smoking has been prohibited in indoor stores, restaurants, bars and other work places in Nebraska since 2009, when the state’s Clean Indoor Air Law went into effect.

Since then, many apartment owners in North Platte and other communities have adopted policies prohibiting smoking in their buildings. Many residents have adopted smoke-free policies for their own homes and vehicles.

In addition, many communities across the state now prohibit smoking in portions or all of their public park systems. Locally, they include North Platte, Gothenburg, Maxwell, Sutherland, Chappell, Lewellen and Big Springs.

The new research was reported on May 19 in Environmental Health Perspectives, vol. 129 no. 5. It was funded through the U.S. National Institutes of Health and the Duke Comprehensive Cancer Center at Duke University in Durham, N.C. Researchers were from Duke, North Carolina State and Virginia Commonwealth Universities.

“These novel findings suggest that even low levels of smoke exposure during pregnancy may be sufficient to alter DNA methylation in distinct sites of mixed umbilical cord blood leukocytes in pathways that are known to be altered in cord blood from pregnant active smokers,” reads the report.