Influence of maternal cigarette smoking during pregnancy on neonatal serum folate levels

Folate is an essential micronutrient for fetal development because of its role in de novo synthesis of DNA. The aim of this study was to compare neonatal serum folate levels of babies born to smoking and non-smoking mothers.

Infants of consenting pregnant mothers presenting at ≥37 weeks of gestation were enrolled. Subjects were divided into two groups based on their mother's smoking habits. Blood samples were obtained at birth (from the umbilical cord) and 1 month after delivery for the determination of serum folate levels using a chemiluminescence method.

Among 140 consenting subjects, 108 (77%) brought their newborns to their scheduled visit 1 month after delivery, 68 of whom were non-smokers and 40 were smokers. Babies born to smoking mothers had significantly lower serum folate levels compared to those born to non-smoking mothers, both at birth (17.2 ± 5 vs. 24.3 ± 4.9; p < 0.01) and 1 month after delivery (11 ± 4.1 vs. 17.5 ± 4.3; p < 0.01).

Our study is the first of its kind to demonstrate that smoking results in significant reductions in serum folate levels of newborns. These results suggest that folic acid supplementation may be required for expectant smoking mothers throughout pregnancy, not just during the first trimester. Similar supplementation may also be warranted for infants born to such mothers.