Researchers at Yale and Brown Universities conducted a prospective cohort study to investigate alcohol consumption during pregnancy and the risks of intrauterine growth retardation (IUGR), low birth weight, reduced head circumference, preterm delivery, and selected congenital malformations.
The study population consisted of pregnant women with singleton gestations resulting in a live birth who were enrolled in 2 related prospective longitudinal cohort studies (1996–2000). All women completed a baseline interview before 24 weeks’ gestation examining multiple risk factors and demographic characteristics. Information regarding alcohol consumption was collected at baseline to assess alcohol consumption during months 1–3 of gestation and postpartum (to assess the third trimester). Second trimester consumption was not assessed. Alcohol content of beverages was summed using a previously established algorithm and expressed as standard “drinks” (a standard drink contained 0.5 oz of alcohol). First trimester exposure was categorized into abstinent, drinking during the first month only, and drinking during months 1–3. Infant outcomes were obtained by medical record review and included low birth weight (<2,500 grams), preterm birth (<37 weeks’ gestation), IUGR (birth weight <10th percentile for gestation), small head circumference (<10th percentile at birth), and selected congenital malformations. The risk of these outcomes was compared, using regression analyses, in infants whose mothers were abstinent during the first trimester, drank alcohol only in month 1 of gestation, and drank alcohol throughout the first trimester. Potentially confounding variables were included in the analyses.
Data were collected on 4,496 mother/infant dyads. Alcohol was consumed by 29% of women during the first month of pregnancy and declined in the second (9%) and third (7%) months. Among women who drank alcohol during months 1, 2, and 3 of gestation, median exposure was 1 drink/week, slightly less than one half drink/week, and slightly less than one third of a drink/week, respectively. The proportion of women drinking alcohol increased during months 7 (11%) and 8–9 (27%).
Among the study cohort, 4.7% of infants were low birth weight, 6.9% were born preterm, and 7.9% had IUGR. In multivariate analyses, neither alcohol consumption during month 1 of gestation nor drinking alcohol throughout the first trimester was associated with an increased risk for any of the assessed infant outcomes. First trimester drinking was associated with reduced risk for low birth weight (OR = 0.66; 95% CI, 0.46–0.96), birth length <10th percentile (OR = 0.56; 95% CI, 0.36–0.87), and head circumference <10th percentile (OR = 0.69; 95% CI, 0.50–0.96).
The authors conclude that there was no evidence in this cohort of women that low-to-moderate maternal alcohol consumption during early gestation was associated with the assessed adverse outcomes in infants.
Dr Holmes has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use...