Fetal exposure to maternal active and secondhand smoking with offspring early-life growth in the Healthy Start study

Int J Obes (Lond). 2019 Apr;43(4):652-662. doi: 10.1038/s41366-018-0238-3. Epub 2018 Oct 19.


Background: Previous studies have modeled the association between fetal exposure to tobacco smoke and body mass index (BMI) growth trajectories, but not the timing of catch-up growth. Research on fetal exposure to maternal secondhand smoking is limited.

Objectives: To explore the associations between fetal exposure to maternal active and secondhand smoking with body composition at birth and BMI growth trajectories through age 3 years.

Methods: We followed 630 mother-child pairs enrolled in the Healthy Start cohort through age 3 years. Maternal urinary cotinine was measured at ~ 27 weeks gestation. Neonatal body composition was measured using air displacement plethysmography. Child weight and length/height were abstracted from medical records. Linear regression models examined the association between cotinine categories (no exposure, secondhand smoke, active smoking) with weight, fat mass, fat-free mass, and percent fat mass at birth. A mixed-effects regression model estimated the association between cotinine categories and BMI.

Results: Compared to unexposed offspring, birth weight was significantly lower among offspring born to active smokers (-343-g; 95% CI: -473, -213), but not among offspring of women exposed to secondhand smoke (-47-g; 95% CI: -130, 36). There was no significant difference in the rate of BMI growth over time between offspring of active and secondhand smokers (p = 0.58). Therefore, our final model included a single growth rate parameter for the combined exposure groups of active and secondhand smokers. The rate of BMI growth for the combined exposed group was significantly more rapid (0.27 kg/m2 per year; 95% CI: 0.05, 0.69; p < 0.01) than the unexposed.

Conclusions: Offspring prenatally exposed to maternal active or secondhand smoking experience rapid and similar BMI growth in the first three years of life. Given the long-term consequences of rapid weight gain in early childhood, it is important to encourage pregnant women to quit smoking and limit their exposure to secondhand smoke.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Birth Weight / drug effects*
  • Body Mass Index
  • Breast Feeding / statistics & numerical data
  • Cotinine / urine*
  • Female
  • Humans
  • Infant, Newborn
  • Longitudinal Studies
  • Maternal Exposure / adverse effects*
  • Maternal Nutritional Physiological Phenomena
  • Mothers* / education
  • Mothers* / psychology
  • Patient Education as Topic
  • Plethysmography
  • Pregnancy
  • Smoking / adverse effects*
  • Smoking / epidemiology
  • Smoking Cessation / psychology
  • Smoking Cessation / statistics & numerical data*
  • Tobacco Smoke Pollution / adverse effects*
  • Tobacco Smoke Pollution / statistics & numerical data


  • Tobacco Smoke Pollution
  • Cotinine