Racial patterns in the effects of tobacco use on fetal growth

OBJECTIVE: The aim of this study was to characterize the interaction betwee n the effects on fetal growth of maternal smoking and race by means of race -specific growth normograms. STUDY DESIGN: A case-control study was performed on white and African Ameri can mothers who were delivered at 2 hospitals in metropolitan Atlanta betwe en February 1993 and December 1994. The study population consisted of 621 s mall for gestational age infants and their mothers and 324 appropriate for gestational age infants and their mothers. Face-to-face interviews with mot hers and detailed anthropometric measurements of neonates were performed. R elationships among tobacco use, race, and fetal growth were evaluated by me ans of multiple logistic regression. The chi(2) test of trend was performed to assess a dose-response relationship between smoking and fetal growth. RESULTS: Mothers of small for gestational age neonates were significantly m ore likely than control mothers to be single (52% versus 40%), to be primip arous (47% versus 37%), to have a low body mass index (26% versus 17%), to have hypertension (22% versus 15%), and to use alcohol (15% versus 9%). Mot hers of small for gestational age infants were significantly more likely th an control mothers to smoke (26% versus 12%) and to smoke more cigarettes ( P < .05). After controlling for potential confounders cigarette smoking in the second trimester was significantly associated with small for gestationa l age infants in both races (whites <1 pack/d adjusted odds ratio 3.82, 1-2 packs/d adjusted odds ratio 4.86, >2 packs/d crude odds ratio; African Ame ricans <1 pack/d adjusted odds ratio 2.35, 1-2 packs/d adjusted odds ratio 2.52). The chi(2) test of trend results were consistent with a dose-respons e relationship between smoking and small for gestational age infants (white s chi(2) = 14.06, P < .0001, African Americans chi(2) = 7.99). Comparison b etween the 2 races of the adverse effects of smoking on fetal growth showed no significant difference. CONCLUSION: Self-reported maternal smoking during the second trimester is a ssociated with fetal growth restriction in a dose-response manner. Accordin g to race-specific growth normograms no significant difference in the effec ts of tobacco use on fetal growth was found between white and African Ameri can women.