BACKGROUND AND PURPOSE:

• Smoking is an independent risk factor for type 2 diabetes
• Bar-Zeev et al. (Obstetrics & Gynecology, 2020) investigated whether there is an association between prenatal smoking and gestational diabetes mellitus (GDM)

METHODS:

• Secondary data analysis of the Pregnancy Risk Assessment Monitoring System (2009-2015)
  • CDC and state health departments surveillance project
• Participants
  • Representative sample of U.S. women with recent live births
• Study design
  • Data extraction on smoking status during pregnancy
    • Nonsmoker
    • Quit smoking
    • Reduced the amount smoked
    • Smoked the same or more
  • Multivariable logistic regression analyses to estimate the association between prenatal smoking and GDM status
  • Adjusted for confounders, including
    • Maternal age | Race–ethnicity | Prepregnancy BMI | Gestational weight gain
  • Overall associations were estimated | Stratification conducted using prepregnancy BMI and gestational weight gain subgroups
• Primary outcomes
  • Self-reported GDM

RESULTS:

• 222,408 women included
  • GDM: 5.3%
  • Excessive weight gain: 43.1%  
• Smoking status
  • Nonsmokers for >2 years before pregnancy: 75.0%
  • Quit before pregnancy: 2.8%
  • Quit during pregnancy: 11.8%
  • Reduced number of cigarettes smoked: 6.7%  
  • Number of cigarettes same or more: 3.5%
• There was a significant association between prenatal smoking and GDM
  • Smoked the same or greater number of cigarettes during pregnancy
    • Adjusted odds ratio (aOR) 1.46 (95% CI, 1.25 to 1.71)
  • Reduced the number of cigarettes smoked during pregnancy
    • aOR 1.22 (95% CI, 1.08 to 1.38)
• Subgroup analysis
  • Association between smoking the same or more cigarettes was associated with higher odds of GDM in all subgroup of prepregnancy BMI or gestational weight gain

CONCLUSION:

• Prenatal smoking is associated with a higher risk for GDM, and remained an independent risk factor after adjustment for confounders and weight stratification
  • Study strengths include large sample size and rigorous data collection from multiple states
• Authors recognize study limitations including
  • Secondary analysis of database and therefore not all confounders were accounted for (e.g., family history of diabetes and activity levels)
• The authors suggest that “reducing smoking rates may reduce the risk of GDM” and as a modifiable risk factor, this study provides further evidence to discourage smoking during pregnancy

Learn More – Primary Sources:

Association Between Prenatal Smoking and Gestational Diabetes Mellitus

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