Mar 5, Nursing should take place 2 hours or longer after the alcohol intake to Koren G. Drinking alcohol while breastfeeding: Will it harm my baby?. Mar 31, Drinking while nursing may not be illegal, but experts say large amounts of alcohol can be harmful for a breastfeeding baby. So are smaller. have been observed during the 8 – 16 hours after exposure when mothers refrained from drinking. (2,3,4,5). Things to consider - How much alcohol passes - Do I have to pump and.