Relation of Birth Weight to Maternal Smoking

As maternal smoking has been associated with a reduction in newborn birth weight, our objective in this study is to estimate how the pattern of maternal smoking throughout pregnancy influences newborn size. One hundred twenty pregnant smoking women were enrolled in a prospective study. Data were collected regarding maternal age, education, parity, body mass index and cigarette consumption. Cigarette use was defined as self-reported consumption before pregnancy, at the time of study enrollment, and in the third trimester, statistical analyses were performed based on bivariate correlations and multiple linear regression. Of the smoking parameters examined, maternal thirdtrimester cigarette consumption was the strongest predictor of birth weight percentile (r=-0.25, p 0.001). Pre pregnancy smoking volume was not significantly associated with birth weight percentile (r=0.008, p=0.32). Additional factors contributing to birth weight include gestational age, maternal body mass index and parity. We couclude that maternal third trimester cigarette consumption is a strong and independent predictor of birth weight percentile. This supports the hypothesis that reductions in maternal cigarette consumption during pregnancy will result in improved birth weight, regardless of the pre pregnancy consumption levels.