The Effect of Maternal Smoking during Pregnancy on Early Infant Lung Function

Abstract

We studied the effect of prenatal maternal cigarette smoking on the pulmonary function (PF) of 80 healthy infants tested shortly after birth (mean, 4.2 +/- 1.9 wk). Mothers' prenatal smoking was measured by: (1) questionnaire reports at each prenatal visit of the number of cigarettes smoked per day, and (2) urine cotinine concentrations (corrected for creatinine) obtained at each visit. Infant PF was assessed by partial expiratory flow-volume curves and helium-dilution measurement of FRC. Forced expiratory flow rates were significantly lower in infants born to smoking mothers, both when unadjusted and after controlling for infant size, age, sex, and passive exposure to environmental tobacco smoke (ETS) between birth and the time of PF testing. Flow at functional residual capacity (VFRC) in infants born to smoking mothers was lower than that found in infants whose mothers did not smoke during pregnancy (74.3 +/- 15.9 versus 150.4 +/- 8.9 ml/s; p = 0.0007). Differences remained significant when flow was corrected for lung size (VFRC/FRC: 0.87 +/- 0.26 versus 1.77 +/- 0.12 s-1; p = 0.013). No differences in pulmonary function were evident among infants exposed and unexposed to ETS in the home after stratifying by prenatal exposure status. We conclude that maternal smoking during pregnancy is associated with significant reductions in forced expiratory flow rates in young infants. The results suggest that maternal smoking during pregnancy may impair in utero airway development and/or alter lung elastic properties. We speculate that these effects of maternal prenatal smoking on early levels of forced expiratory flow may be an important factor predisposing infants to the occurrence of wheezing illness later in childhood.

The association between environmental tobacco smoke exposure and childhood respiratory disease: a review

“…ETS exposure in children is associated with lower FEV1 values compared to matched unexposed children [86]. Antenatal maternal smoking has been associated with a reduction in early-life lung function suggesting that in utero smoke exposure may affect airway development and lung elasticity [87]. Maternal smoking during pregnancy and in early life is the most significant source of exposure affecting infant lung function [85].…”

Assessment of chronic exposure to cigarette smoke and its change during pregnancy by segmental analysis of maternal hair nicotine

“…The accurate assessment of fetal exposure to smoking through the objective measure of a biomarker could be of major importance for the investigation of the effects of preand postnatal environmental exposures to pollutants, including tobacco smoke, in the inception of respiratory diseases (Hanrahan et al, 1992;Nafstad et al, 1996Nafstad et al, , 1997Corbo et al, 1996;Lodrup Carlsen et al, 1997;Cook and Strachan, 1998;Strachan and Cook, 1998). Recently, we showed that cord serum cotinine resulted as the most adequate biomarker of fetal exposure to smoking at the end of pregnancy, distinguishing not only active smoking from passive smoking, but also exposure to environmental tobacco smoke (ETS) from nonexposure .…”

Maternal Complications and Procedures in Pregnancy and at Birth and Wheezing Phenotypes in Children

“…The most studied in utero environmental influence on lung development is maternal smoking in pregnancy, which has been shown to be associated not only with wheezing in childhood (2)(3)(4)(5) but also with a dose-related reduction in lung function in the newborn period. Fetal development seems therefore to represent a critical time of pulmonary vulnerability with respect to smoking exposure.…”