Drinking alcohol while breastfeeding can temporarily disrupt both milk production and milk ejection.
2,3 Otherwise known as the ‘let-down’ reflex, milk ejection is the process where milk flows from the breast when a baby starts to feed. Let’s look at the current evidence behind how alcohol could disrupt breastfeeding.
In one (albeit small) study, 22 breastfeeding women were asked to express milk on two different days.3 Researchers found that after having just 1.8 units of alcohol, the women produced 9.3% less milk in the next two hours.3
Another study showed that after drinking around 2.3 units of alcohol, lactating women took longer to eject their milk.4
Alcohol may affect lactation in this way because it lowers oxytocin levels.2 Oxytocin is the hormone that helps the muscles in your breast contract to release milk.2 So, when alcohol reduces oxytocin, it can make it harder for your body to let down milk effectively.
Simply put, alcohol may reduce how much milk you produce and how easily milk is expressed when breastfeeding. However, the research studies are currently very small and limited, and more research needs to be carried out to be sure.
When you breastfeed, traces of what you eat and drink pass through to your breast milk – and alcohol is no exception. Alcohol can pass to your baby when you breastfeed and may cause sleep, growth and developmental problems.2,5