Objective: To explore the relationship between maternal passive smoking during early pregnancy and the risk of neural tube defects (NTDs).
Methods: Data was derived from a population-based case-control study on birth defects in Shanxi province. The study subjects included 515 NTDs defects cases (236 cases of anencephaly, 237 spina bifida and 42 encephalocele) ascertained during January 2003 and June 2007 in the study areas and 682 normal controls randomly selected in the same residence during the same period as cases. RESULTS; The risk of NTDs in their offspring was 1.84 (95% CI: 1.39-2.44) for mothers with passive smoking history during peri-conceptional period. There was a marked dose-response relation between maternal passive smoking and the risk of NTDs in offspring. Compared to the women without passive smoking, the NTDs risk in offspring was 1.51 for women with occasional passive smoking and 2.44 for women with passive smoking for almost everyday during the peri-conceptional period.
Conclusion: Maternal passive smoking during peri-conceptional period increased the risk of NTDs in offspring.