RESUMEN
Passive smoking [PS], a well-known health risk, is the major source of indoor pollution. There is some inconsistent evidence that PS during pregnancy may increase the risk of low birth weight. The aim of the present study was to determine the effects of PS exposure during pregnancy on weight, length and cranial circumference at birth of babies born to women who have described themselves as nonsmokers, in Kerman, Iran. A random sample of 702 admitted women aged 11 to 50 years [mean [standard deviation] 26.5 [6.1]] who delivered a live full-term singleton baby without apparent malformation during the six consecutive months from June to December 1994 were interviewed on the second day post-partum and asked about smoking in all household members. They comprised about 36.4% of total deliveries in Bahonar Kerman Medical School Hospital during this period. All women were nonsmokers, 278 [39.6%] were passive smokers while 424 [60.4%] were not exposed to tobacco smoke. Potential confounders, including fetal gender, maternal age, parity, weight gain, complications during pregnancy, maternal education, birth interval and gestation were adjusted for by multiple linear regression analysis. Infants born to passive smokers were on the average 22 gr.lighter than those born to nonsmokers, albeit this difference was not statistically significant [p = 0.56] [95% confidence interval [CI]: -51, 95.7]. A mean reduction of 0.04cm [95% CI: -0.19,0.27] in birth length and 0.05 cm [95%CI: -0.12, 0.22] in cranial circumference was found. In multiple linear regression model, exposure to PS during pregnancy did not show any effect on weight, length and cranial circumference at birth after adjusting for confounding variables