1. Home>
2. Specialties>
3. Women's Health>
4. Summary and Comment

Another Reason Not to Smoke During Pregnancy

Prenatal exposure to maternal smoking has lasting deleterious effects on lung function in children.

Exposure to environmental tobacco smoke is harmful in many ways. These investigators sought to distinguish between the effects of prenatal and postnatal exposure to parental smoking on lung function in children ages 6–12 years. The researchers conducted a pooled analysis of studies that had used questionnaires to ascertain exposure to smoking, and spirometry to assess various lung function parameters. Poor lung function was defined based on cutoffs in parameters anticipated to delineate the group of subjects with the lowest 5% lung function.

The investigators evaluated data from more than 20,000 children in nine countries. Across the pooled studies, the frequency of reported smoking during pregnancy ranged from less than 5% in Germany to more than 28% in the Netherlands. In North America, the frequency of smoking during pregnancy was reported to be 27%. Smoking during pregnancy was associated with significant decreases in all but one of seven lung function parameters in the offspring, even after controlling for confounding variables. The effects of postnatal exposure to smoking were consistently smaller than the effects of prenatal exposure.

Comment: The consequences of prenatal exposure to smoking include increased risk for sudden infant death syndrome (SIDS), colic, and asthma. This study confirms that smoking during pregnancy has a negative effect on lung function in grade school children. In the U.S., smoking rates during pregnancy are highest among 18- and 19-year-olds. Nonetheless, clinicians should direct tobacco cessation messages to all pregnant women, even if the intervention is brief. One option is the use of nicotine replacement products; according to the American College of Obstetrics and Gynecology, the unknown risks associated with nicotine replacement are likely to be outweighed by the benefits to the fetus of reducing smoking exposure. Unfortunately, 60% to 80% of women who quit smoking during pregnancy resume the habit postpartum. This group should be heavily targeted in postpartum visits.

— Ann J. Davis, MD

Published in Journal Watch Women's Health August 3, 2006

Citation(s):

Moshammer H et al. Parental smoking and lung function in children: An international study. Am J Respir Crit Care Med 2006 Jun 1; 173:1255-63.

• Original article (Subscription may be required)
• Medline abstract (Free)