Tobacco use during pregnancy increases risk for preterm birth

  • Soneji S & al.
  • JAMA Netw Open
  • 5 Apr 2019

  • International Clinical Digest
Access to the full content of this site is available only to registered healthcare professionals. Access to the full content of this site is available only to registered healthcare professionals.

Takeaway

  • Smoking during pregnancy increases risk for preterm birth and represents a preventable public health burden.

Why this matters

  • 7.2% of pregnant women in the United States smoke.
  • Cigarette smoking is associated with intrauterine growth restriction, preterm birth, and developmental delays.
  • Preconception counseling can aid in tobacco cessation prior to pregnancy.

Key results

  • 24.3% of those who smoked cigarettes during the 3 months prior to pregnancy quit during pregnancy.
  • The proportion of preterm birth increased with smoking frequency in the first and second trimesters (ORs; 95% CIs):
    • First trimester:
      • 1-9 cigarettes/day: 1.16 (1.14-1.17).
      • 10-19 cigarettes/day: 1.24 (1.22-1.26).
    • Second trimester:
      • 1-9 cigarettes/day: 1.42 (1.39-1.44).
      • 10-19 cigarettes/day: 1.50 (1.46-1.53).
  • Smoking cessation, especially in early pregnancy, was associated with a reduced risk for preterm birth.

Study design

  • Cohort obtained from the US National Center for Health Statistics between 2011 and 2017.
  • Outcomes included cigarette cessation among women who smoked prior to pregnancy, during first, second, and third trimesters, and incidence of preterm birth.
  • Funding: the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Limitations

  • Smoking may be underreported.
  • Confounders such as second-hand smoke or alcohol use not reported on birth certificates.