Alcohol passes freely into mom’s milk and usually peaks around 30 - 60 minutes after consumption and 60 - 90 minutes when taken with food. It also passes freely out of mom’s milk and her system.
It takes a 120-pound woman two to three hours to eliminate one serving of beer or wine. It takes 13 hours to eliminate one high-alcohol drink. The more alcohol consumed, the longer it takes to eliminate it from the body. The effects of alcohol on the breastfeeding baby are directly related to the amount mom consumes.
Studies have shown when moms drink, babies nurse more frequently but actually consume less milk than those whose moms didn’t drink (between 23 - 27 percent less milk). It also shows that the odor of the milk paralleled the changes in alcohol concentration in the milk (may be effecting baby’s desire for suckling).
Amazingly, the American Academy of Pediatrics Committee on Drugs (1994) considers alcohol compatible with breastfeeding! However, it is know that moderate to heavy alcohol consumption by a breastfeeding mom may interfere with her let-down reflex and inhibit milk intake by the baby. It can cause slow weight gain, drowsiness, deep sleep, weakness, decreased linear growth, and possible psychomotor delay in infants.
Encourage moms to avoid alcohol. If that is not possible, avoid breastfeeding while drinking and for two to three hours after drinking. Adult metabolism of alcohol is approximately one ounce in three hours, so moms who ingest alcohol in moderate amounts can generally return to breastfeeding as soon as they feel neurologically normal, according to Medications and Mother’s Milk, 2000 edition.