Smoking and pregnancy outcome among African-American and white women in central North Carolina

Despite extensive research on tobacco smoking during pregnancy, few studies address risks among African-American and white women, groups that differ i n brand preference and smoking habits. The Pregnancy, Infection, and Nutrit ion Study is a prospective cohort study that included 2,418 women with deta iled information on smoking during pregnancy, including brand, number of ci garettes per day, and changes during pregnancy. We analyzed risk of preterm . birth (< 37 and < 34 weeks' gestation) and small-for-gestational-age deli veries in relation to tobacco use. Pregnant African-American smokers differ ed markedly from whites in brand preference (95% vs 26% smoked menthol ciga rettes) and number of cigarettes per day (1% of African-Americans and 12% o f whites smoked 20+ cigarettes per day). Smoking was not related to risk of preterm birth overall, but cotinine measured at the time of delivery was ( adjusted odds ratio = 2.2, 95% confidence interval = 1.1-4.5). A clear asso ciation and dose-response gradient was present for risk of fetal growth res triction (risk ratio for 20+ cigarettes/day = 2.4, 95% confidence interval = 1.4-4.0). Associations of tobacco use with preterm premature rupture of a mniotic membrane resulting in preterm birth were notably stronger than the associations with other types of preterm birth.