Effect of Maternal Smoking During Pregnancy on Passive Respiratory Mechanics in Early Infancy

Pediatr Pulmonol. 1995 Jan;19(1):23-8. doi: 10.1002/ppul.1950190105.

Abstract

We studied the effect of prenatal maternal cigarette smoking on passive expiratory mechanics in 53 healthy infants tested early in infancy (mean +/- SD, 5.1 +/- 1.5 weeks). Maternal smoking was measured by: 1) questionnaire reports of the number of cigarettes smoked per day; and 2) urine cotinine concentrations (corrected for creatinine) at each visit. Respiratory system mechanics were assessed by the single-breath occlusion-passive-flow-volume maneuver. In ten infants born to smoking mothers the time constant of the respiratory system was 23% reduced [0.34 vs. 0.44 s; 95% confidence interval (CI), -45% + 1%; P = 0.06]. This was related to an estimated 13% decrease in respiratory system compliance (4.86 vs. 5.62 mL/cmH2O; 95%CI, -33% + 6%; P = 0.18) and a 10% reduction in respiratory system resistance (0.073 vs. 0.081 cm H2O/mL/s; 95%CI, -42% + 22%; P = 0.56). Functional residual capacity (FRC), measured by helium-dilution, was also decreased by 13% (78 vs. 90 mL; 95%CI, -27% + 0.3%; P = 0.06) in smoke-exposed infants. Forced expiratory flow rates at FRC obtained by thoraco-abdominal compression were reduced by 28% in infants of smoking mothers (VFRC, 99 vs. 138 mL/s; 95%CI, -54% + 2%; P = 0.04) as reported previously in a larger sample from this population. This study was limited by small numbers of infants exposed to smoking during pregnancy and by ethnic imbalance among the smoking-exposed and unexposed groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Confidence Intervals
  • Female
  • Forced Expiratory Flow Rates
  • Humans
  • Infant
  • Infant, Newborn
  • Lung / physiopathology*
  • Lung Volume Measurements
  • Male
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • Respiratory Function Tests*
  • Smoking / adverse effects*
  • Smoking / physiopathology
  • Spirometry
  • Surveys and Questionnaires
  • Tobacco Smoke Pollution / adverse effects
  • Vital Capacity

Substances

  • Tobacco Smoke Pollution