A recent study examined the association between maternal alcohol consumption in early pregnancy and pregnancy outcomes including low-birth-weight, spontaneous preterm birth and pre-eclampsia.1 Many women continue to consume alcohol in pregnancy despite recommendations that they should abstain from alcohol in order to minimise potential risks to the fetus. The advice from the departments of health in Ireland and the United Kingdom (UK) and the Surgeon General in the United States is that alcohol should be avoided during pregnancy. However, the National Institute for Health and Clinical Excellence in the UK states that there is no consistent evidence of adverse effects from low to moderate prenatal alcohol consumption and recommends that women should be advised to drink no more than 8 grams of pure alcohol/1 standard drink once or twice a week.
This study involved 5,628 women who had not previously given birth, recruited in New Zealand, Australia, the UK and Ireland. Participants were interviewed at 15 weeks of gestation and information on alcohol intake before pregnancy and up to the time of interview was obtained using a standardised questionnaire. Alcohol intake was classified as occasional (8–16 grams of alcohol /1-1.5 standard drinks per week), low (24–56 grams of alcohol /2.5-5.5 standard drinks per week), moderate (64–112 grams of alcohol/6-11 standard drinks per week), and heavy (more than 112 grams of alcohol/11 standard drinks per week). Binge alcohol consumption was defined as consumption of 48 grams of alcohol/5 standard drinks in one session.
The majority of participants (60%) consumed some alcohol in pregnancy; 1,090 (19%) reported occasional consumption, 1,383 (25%) low consumption, 625 (11%) moderate consumption, and 300 (5%) heavy consumption. Overall, 1,905 (34%) participants reported binge drinking in the three months before pregnancy, and 1,288 (23%) reported binge drinking during the first 15 weeks of pregnancy. Significant geographical variation was observed between study centres: 65%–80% of participants in the UK and Ireland consumed some alcohol in pregnancy, compared with 38% in Australia and 53% in New Zealand. Participants who consumed occasional to heavy amounts of alcohol in early pregnancy did not have altered odds of a small-for-gestational-age neonate, reduced birth weight, pre-eclampsia, or spontaneous preterm birth. Similarly, those who binge drank in early pregnancy did not have altered odds of these adverse pregnancy outcomes.
The authors of the study concluded that there was no association between alcohol consumption before 15 weeks of gestation and small-for-gestational-age neonate, reduced birth weight, pre-eclampsia, or spontaneous preterm birth. It remains unclear whether any safe level of alcohol consumption in pregnancy exists, and there is currently inadequate information to determine whether there are discrete gestational windows of vulnerability for different adverse outcomes. It should also be noted that this study did not evaluate the association between alcohol consumption in pregnancy and long-term neurocognitive outcomes of children exposed as fetuses to alcohol. This potential for neurocognitive dysfunction remains one of the single most important reasons for pregnant women to avoid alcohol intake during pregnancy.
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McCarthy FP, OʼKeeffe LM, Khashan AS et al. (2013) Association between maternal alcohol consumption in early pregnancy and pregnancy outcomes. Obstetrics And Gynecology, 122: 830–837. www.drugsandalcohol.ie/20527
