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

ABSTRACT

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.