EFFECTS OF ALCOHOL-USE, SMOKING, AND ILLICIT DRUG-USE ON FETAL GROWTHIN BLACK INFANTS

Study objectives: To compare the effects of prenatal exposure to alcoh ol, smoking, and illicit drugs on birth size. Design: Prospective, lon gitudinal correlational study, with statistical control for confoundin g. Participants: Four hundred seventeen black infants. Mothers recruit ed at first prenatal clinic visit on the basis of moderate-to-heavy us e of alcohol or cocaine or both, plus a 5% random sample of lower-leve l drinkers and abstainers. Main results: Alcohol, smoking, opiates, an d cocaine were each correlated with smaller birth weight, length, and head circumference (median r= -0.21; p <0.001). However, when all four substances, gestational age, and six covariates were controlled stati stically, birth weight related only to alcohol and smoking (p <0.05), length only to alcohol (p <0.05), and head circumference only to opiat es (p <0.01). Although smoking affected birth weight at all levels of exposure, a larger deficit was seen in relation to heavy drinking (509 gm) than to heavy smoking (269 gm). Alcohol and smoking did not affec t birth size synergistically, and their effects were seen primarily in infants of women more than 30 years of age. Conclusions: The associat ion of reduced birth weight and length with illicit drug use may be a consequence of simultaneous exposure of the fetus to alcohol and smoki ng. Opiate exposure is specifically related to reduced head circumfere nce, and the effect of cocaine on birth size is primarily an indirect consequence of shorter gestation and poorer maternal nutrition.