Maternal smoking during pregnancy and neural tube defects in offspring: a meta-analysis

Purpose This study aims to examine the association between maternal smoking during pregnancy and neural tube defects (NTDs) in offspring. Methods We retrieved published studies on the association between maternal smoking during pregnancy and NTDs risk in offspring. Meta-analysis was applied to calculate the overall odds ratios (ORs) and their 95 % confidence intervals (CIs). The publication bias was assessed by the Egger’s regression asymmetry test and Begg’s rank correlation test. Results The overall effect of maternal smoking during pregnancy on NTDs was 1.03 (OR = 1.03, 95 % CI = 0.80–1.33). When subgroup analysis was conducted by geographic regions, the overall effects were 1.39 (OR = 1.39, 95 % CI = 1.18–1.64), 0.88 (OR = 0.88, 95 % CI = 0.66–1.17) in Europe and USA; when subgroup analysis was conducted by NTDs types, the overall effect was 1.55 (OR = 1.55, 95 % CI = 1.06–2.26) for spina bifida. Conclusions Women who smoked during pregnancy had mildly elevated risk of having infants with NTDs.