Association between maternal alcohol consumption during pregnancy and risk of preterm delivery: the Japan Environment and Children's Study.

<bold>Objective: </bold>To examine the association between maternal alcohol consumption during pregnancy and the risk of preterm delivery.<bold>Design: </bold>Prospective cohort study.<bold>Setting: </bold>The Japan Environment and Children's Study (JECS).<bold>Population: </bold>A total of 94 349 singleton pregnancies.<bold>Methods: </bold>Participants completed questionnaires detailing alcohol consumption during the first trimester and during the second and third trimesters. Participants were divided into four categories according to alcohol consumption (non-drinkers, consumers of 1-149 g, 150-299 g and ≥300 g ethanol/week). We examined the effect of alcohol consumption during different stages of pregnancy on the risk of preterm delivery. Odds ratios (OR) and 95% CI were calculated relative to non-drinkers using logistic regression.<bold>Main Outcome Measures: </bold>Medical record-based preterm delivery.<bold>Results: </bold>Alcohol consumption during the second and third trimesters, but not during the first trimester, was associated with increased risk of preterm delivery. Heavy alcohol consumption (≥300 g ethanol/week) during the second and third trimesters was associated with a four-fold higher risk compared with non-drinkers (multivariable OR 4.52; 95% CI 1.68-12.2). Light alcohol consumption (1-149 g ethanol/week) tended to be associated with lower risk of preterm delivery (multivariable OR 0.78; 95% CI 0.60-1.00).<bold>Conclusions: </bold>Heavy alcohol consumption during the second and third trimesters was associated with increased risk of preterm delivery among pregnant women.<bold>Tweetable Abstract: </bold>Heavy drinking during pregnancy may increase the risk of preterm delivery. [ABSTRACT FROM AUTHOR]