Does alcohol increase the risk of preterm delivery?

We evaluated the association between alcohol intake during pregnancy and pr eterm delivery. Women attending routine antenatal care at Aarhus University Hospital, Denmark, from 1989-1991 and 1992-1996 were eligible. We included 18,228 singleton pregnancies in the analyses. We obtained prospective info rmation on alcohol intake at 16 and 30 weeks of gestation, other lifestyle factors, maternal characteristics, and obstetrical risk factors from self-a dministered questionnaires and hospital files. For women with alcohol intak e of 1-2, 3-4, 5-9, and greater than or equal to 10 drinks/week the risk ra tio (RR) of preterm delivery was 0.91 (95% CI = 0.74-1.08), 0.86 (95% CI = 0.64-1.15), 0.89 (95% CI = 0.52-1.52), and 2.93 (95% CI = 1.52-5.63), respe ctively, compared with intake of <1 drink/week at 16 weeks gestation, and 0 .69 (95% CI = 0.56-0.86), 0.82 (95% CI = 0.60-1.13), 0.97 (95% CI = 0.58-1. 64), and 3.56 (95% CI = 1.78-7.13) at 30 weeks. Adjustment for smoking habi ts, caffeine intake, age, height, pre pregnant weight, marital status, occu pational status, education, parity, chronic diseases, previous preterm deli very, mode of initiation of labor, anal sex of the child did not change the conclusions, nor did restriction of the: highest intake group to women dri nking 10-14 drinks/week (RR = 3.41 (1.71-6.81) at 16 weeks and RR = 3.47 (1 .64-7.35) at 30 weeks).