Drinking beer while breastfeeding has long been touted as a way to both increase milk supply and lessen the time it takes for the milk to let down. Studies of these benefits of drinking beer while breastfeeding have had mixed results, with the majority showing there is no real basis to these beliefs. It is known that beer, or any alcohol, can actually reduce a woman's milk supply when consumed in excess. Most major medical organizations, however, consider moderate alcohol consumption to be compatible with nursing.
For centuries, beer has been used by breastfeeding mothers, especially in the early stages of a nursing relationship, to increase milk supply and flow. It is believed that the hops in beer, both alcoholic and nonalcoholic, increase a woman's prolactin levels, causing her body to produce more milk and aiding in the flow of milk from breast to baby or pump, also known as milk let down. While there is a large amount of anecdotal evidence supporting this theory, scientific studies have not produced the same results.
Several researchers have found that for prolactin levels to increase significantly enough to cause the body to produce more milk, a large amount of beer would need to be consumed. As beer is a diuretic, the quantity needed would actually dry up a mother's milk, despite the increase in prolactin. Smaller studies, however, have found that drinking beer while breastfeeding can help a mother relax, thereby aiding in milk let down. A small glass of beer can generally achieve this effect without limiting milk supply or causing any harm to the baby.
Drinking beer while breastfeeding is often looked down on upon. Yet according to various breastfeeding organizations, and many major medical organizations including the American Academy of Pediatrics (AAP) and the World Health Organization (WHO), nursing mothers can safely drink beer, as well as other types of alcohol, while breastfeeding. The general consensus is that if a woman is sober enough to legally drive, she is sober enough to nurse her child. This means that a woman weighing about 140 pound (63 kilograms) can safely have one 12-ounce (355 ml) beer or one 5-ounce (148 ml) glass of wine every two hours with food, and still nurse her child without an issue.
If a woman wishes to consume more than this recommended amount, most doctors suggest pumping beforehand and feeding the baby with a bottle even though alcohol generally does not stay in breast milk. The breasts themselves often filter out a large amount of impurities from the milk as well. Constant exposure to alcohol in breast milk, however, has been found to slow a baby's development of gross motor skills and, in children under three months of age, make them groggy or gassy.