Maternal smoking, environmental tobacco smoking and low birthweight

Objectives: Many studies have suggested that maternal smoking is a risk factor for low birth weight (LBW). The effect of environmental tobacco smoking (ETS) on LBW remains controversial. While few studies on these issues have been conducted in Taiwan, we initiated a preliminary study in Hsi Chih. Methods: In the survey on low frequency magnetic field and health effect in Hsi Chih, women aged 15 years and above were interviewed for information about reproductive health and life style in regard to smoking and secondary hand smoking. Risks for LBW were investigated among women who were living in Hsi Chih during the first pregnency. Results: Among the 2074 eligible women living in Hsi Chih when they were pregnant, 4.9% were smokers and 61.4% were exposed to ETS. Maternal smoking contributed to the elevated risk of LBW but not significant (odds ratio (OR)=1.63, 95% confidence interval (CI) 0.65-4.07). Compared to the women with non-smoking spouses, the OR for having LBW births is 3.16 (95% CI 1.38-7.21) for women with smoking partners who smoke 21 or more cigarettes daily. Conclusion: This study suggests that pregnant women need education to be aware of the fact that heavy ETS exposure is a risk factor of giving LBW infant.