Drinking large amounts of alcohol in pregnancy increases the risk of very preterm birth, a new study finds. Medical News Today reports that the study found high consumption of alcohol increased the risk of having a baby less than 32 weeks into the pregnancy.

The new study, published in Biomed Central’s open access journal BMC Pregnancy and Childbirth, examined how much alcohol women drank during their early weeks of pregnancy and what effect this had on their babies.

The study, conducted in Ireland, included more than 60,000 pregnant women, who were interviewed approximately 10-12 weeks into their pregnancy. Their answers were compared with data from their baby’s birth record and to records from the hospital’s baby care unit. Only two women in 1,000 said they were heavy drinkers, meaning they drank more than 20 units per week. These women were most likely to be young and also to have used illegal drugs. While heavy drinking was related to very premature birth, the researchers did not find the amount of alcohol a woman drank and the occurrence of birth defects in her baby.