Nicotine consumption and folate insufficiency in pregnancy: a population-based cross-sectional study.

OBJECTIVE: Tobacco smoking and folate insufficiency are both risk factors associated with adverse pregnancy outcomes, but their association in pregnancy remains unclear. This study investigated the association between tobacco smoking and folate insufficiency in pregnant women in the U.S. METHODS: Data from nine consecutive cycles of the National Health and Nutrition Examination Survey (2003-2020) were analyzed. Smoking status was derived from serum cotinine levels, and folate insufficiency was determined based on World Health Organization guidelines. The Rao-Scott test of independence was used to assess the prevalence of smoking and folate insufficiency across sociodemographic subgroups, and survey-weighted logistic regression models were used to evaluate the association between smoking and folate insufficiency. RESULTS: Both smoking and red blood cell (RBC) folate insufficiency showed high prevalence among non-Hispanic Black subgroups with an education level of high school or less. Compared to pregnant nonsmokers, pregnant smokers faced increased odds of RBC folate insufficiency (OR: 1.87; 95% CI: 1.10, 3.19). Approximately 3.6% (95% CI: 1.4, 6.4%) of cases of RBC folate insufficiency among pregnant women in the U.S. were associated with active smoking. CONCLUSIONS: Tobacco smoking increases the risk of insufficient folate stores among pregnant women. However, healthcare providers should assess the folate status of all pregnant women and consider proactive screening, such as RBC folate testing, complemented by integrated strategies addressing tobacco use and nutritional risk. Proactive screening for smokers should be revisited once the prevalence of insufficient folate stores has been reduced at the population level.