Most new mothers are told, at one time or another, that if they drink a beer, it will help to increase breast milk supply. Or by drinking a glass of wine, the let-down reflex will improve. But does it? Let’s look at the history of the advice and the research about alcohol. Although these common suggestions have been around for centuries, this is an instance which science does not support.
Older studies in animals suggest that beer, or more likely the barley within the beer, may stimulate prolactin levels (Hale, 2014). But current research shows clearly that alcohol is a profound inhibitor of oxytocin release, which reduces let-down as well as the amount of milk transferred by the infant at breast. Hale sites multiple studies which indicate that even the equivalent of 1 can of beer for the average sized woman dramatically reduces milk production (23%) as well as milk consumption by infants for up to 12 hours, since the reduction in let-down is dose-dependent. In other words, the more drinks the mother takes in, the lower the milk ejection reflex, and the lower the milk intake by the infant. He states that excess alcohol levels lead to drowsiness, deep sleep, weakness and decreased linear growth in infants.
A new study suggests that the state of lactation itself changes the metabolic rate for alcohol clearance, indicating that the alcohol is cleared more quickly in the system of a lactating mother. The study, however, says that the infant effects were still similar. Hale recommends waiting at least two hours per drink with moderate drinking (2 drinks/week) before resuming breastfeeding. Chronic or heavy consumers should not breastfeed at all.
Alcohol has a very small molecular weight, is not protein bound at all, and is 100% bioavailable to the infant. This means alcohol transfers into human milk with an average milk/plasma ratio of one. Alcohol is noted as, “Use with caution, not recommended”. The infant should be monitored for sedation and poor feeding; mother should be monitored for decreased milk supply and altered milk taste.
Kathy Parkes, MSN-Ed, BSPsy, RN, IBCLC, RLC, FILCA