© 2001 Elsevier Science Inc. All rights reserved. 1047-2797/01/$–see front matter 655 Avenue of the Americas, New York, NY 10010 PII S1047-2797(01)00240-X INTRODUCTION Numerous studies have evaluated maternal alcohol consump- tion and birth weight. Abel and Hannigan (1) reviewed many prospective studies of maternal alcohol consumption and low birth weight (2500g at term) published before 1995. Some studies reported an association between moderate maternal alcohol consumption and low birth weight (2–6); other stud- ies did not find the association (1). A number of other studies examined the relation between maternal alcohol consump- tion and intrauterine growth retardation (IUGR), defined for epidemiologic surveillance by birthweight less than the 5th or 10th percentile for gestational age. Similar to the studies of A Case-Control Study of Maternal Alcohol Consumption and Intrauterine Growth Retardation QUANHE YANG, PhD, BERNADETTE B. WITKIEWICZ, MS, RICHARD S. OLNEY, MD, MPH, YECAI LIU, MS, MARGARETT DAVIS, MD, MPH, MUIN J. KHOURY, MD, PhD, ADOLFO CORREA, MD, PhD, AND J. DAVID ERICKSON, DDS, PhD PURPOSE: Heavy maternal drinking during pregnancy causes fetal alcohol syndrome, but whether more moderate alcohol consumption is associated with such adverse pregnancy outcomes as intrauterine growth retardation (IUGR) remains controversial. METHODS: Using data from a case-control study, we examined the association between maternal alco- hol consumption and risk for IUGR among 701 case and 336 control infants born during 1993-1995 in Monroe County, New York. RESULTS: Our results provide no evidence of an independent association between moderate maternal alcohol consumption (14 drinks per week) and risk for IUGR. The risk for IUGR among heavy drinkers (14 drinks per week) around the time of conception was OR = 1.4 (95% CI 0.7–2.6) for IUGR  5th percentile and OR = 1.4 (95% CI 0.7–2.8) for IUGR 5th–10th percentile. For heavy drinkers during the first trimester, the OR was 1.3 (95% CI 0.4–4.5) for IUGR  5th percentile and OR = 1.3 (95% CI 0.4– 4.8) for IUGR 5th–10th percentile. CONCLUSIONS: Since IUGR is a heterogeneous outcome with a possible multifactorial origin, further studies are needed to examine the combined effects of alcohol and other environmental and genetic fac- tors on IUGR risk for subgroups of IUGR. Ann Epidemiol 2001;11:497–503. © 2001 Elsevier Science Inc. All rights reserved. KEY WORDS: Alcohol Drinking, Pregnancy, Birthweight, IUGR, Case-Control Study. maternal drinking and low birth weight, some studies found associations (7–9), and others reported no association be- tween moderate maternal drinking and IUGR (10–12). The inconsistent findings about maternal alcohol consumption and birth weight may reflect differences in study methods, in- cluding assessment of alcohol consumption, control of poten- tial confounders, and sample size. We conducted a case-control study designed to measure the association between levels of maternal alcohol con- sumption and IUGR while controlling for potential con- founding variables. As others have done, we also examined the possible interaction effects of maternal drinking and smoking during pregnancy for risk of IUGR (3–5, 12). MATERIALS AND METHODS Case Ascertainment and Control Population Selection The Centers for Disease Control and Prevention (CDC) and the Monroe County Department of Health conducted in Monroe County, New York, during 1993–1995, a popu- lation-based case-control study of maternal alcohol drink- ing and IUGR. The study used 1983–1986 birth certificate data from upper New York state to estimate 5th and be- tween 5th and 10th percentile distribution of birth weight by gestational age, adjusted for gravidity, race, and From the National Center on Birth Defects and Developmental Disabil- ities, Centers for Disease Control and Prevention, Atlanta, GA (Q.Y., R.S.O., Y.L., A.C., J.D.E.); the Monroe County Department of Health, Rochester, NY (B.B.W.); the Global AIDS Program, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Preven- tion, Atlanta, GA (M.D.); and the Office of Genetics and Disease Preven- tion, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA (M.J.K.). Address reprint requests to: Quanhe Yang, the National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, 4770 Buford Highway, MS F-45, Atlanta, GA 30341. Received November 20, 2000; revised March 21, 2001; accepted March 28, 2001.