Bottles Up, Weight Down: The Relationship between Alcohol Consumption in Pregnancy and the Risk of Delivering a Small for Gestational Age Infant

ABSTRACT

OBJECTIVE: We set out to evaluate the association between maternal alcohol intake in pregnancy and the risk of small for gestational age (SGA) birth in a large cohort of pregnant women.

STUDY DESIGN: A retrospective cohort analysis of singleton births in Missouri that occurred in the period 1989 through 1997 (N= 655,724). We used Cox proportional hazards regression to generate adjusted risk estimates for SGA associated with maternal alcohol intake. We employed the Robust Sandwich Estimator to adjust for intracluster correlations among sibships.

RESULTS: A total of 63,318 counts of SGA were identified, yielding an overall SGA rate of 9.7%. Among mothers who consumed alcohol during pregnancy the SGA rate was 15.9%. Mothers who consumed alcohol while pregnant were 30% more likely to deliver a SGA infant than non-drinking mothers (adjusted hazards ratio [AHR]= 1.3, 95% confidence interval [CI]: 1.2–1.3). A dose-response relationship was also evident; mothers who drink 1-2 and 3-4 drinks per week were 10% (AHR= 1.1; 95%CI: 1.1-1.2) and 50% (AHR= 1.5; 95%CI: 1.3-1.7) respectively more likely to experience a SGA birth compared to mothers who abstain. An SGA birth was twice as likely to occur among women who consumed 5 or more drinks per week during pregnancy than among non-drinking mothers (AHR= 2.1; 95%CI: 1.9–2.4), P for trend <0.01.

CONCLUSION: In summary, we found that in-utero exposure to alcohol impairs fetal growth and development in a dose-dependent fashion. Our findings underscore the need to reinforce current counseling strategies toward pregnant women on the detrimental effects of alcohol use in pregnancy.