Smoking during pregnancy or low social status - Which is the better predictor for low birth weight?

Background and Purpose: Smoking prevalence during pregnancy usually depends on social status. Our aim was to evaluate the influence of intrauterine to bacco exposure and social status on birth weight. Material and Methods: The investigation is based on data from a prospective multicenter atopy study (MAS90) carried out in four University hospitals a nd two municipal hospitals in Western Germany. We included 5395 (71 %) newb orn babies delivered in 1990 and their mothers. Data was supplied by a ques tionnaire, taken during the first week after childbirth, and analysed using both bivariate and multivariate linear regression. Results: 28.6% of the interviewed women smoked during pregnancy. Newborns, of women with lower educational status weighed less than those of women wit h higher educational status (p = 0.06). This difference became statisticall y significant (p < 0.001) in cases were the mother smoked during pregnancy. Conclusion: In Western Germany the influence of the educational level of pr egnant women on their babies' birth weight seems to be smaller than the imp act of smoking.