Breast-feeding and alcohol don't mix well. There's no level of alcohol in breast milk that's considered safe for a baby to drink.
When you drink alcohol, it passes into your breast milk at concentrations similar to those found in your bloodstream. Although a breast-fed baby is exposed to just a fraction of the alcohol his or her mother drinks, a newborn eliminates alcohol from his or her body at only half the rate of an adult.
Research suggests that breast-fed babies who are exposed to one drink a day might have impaired motor development and that alcohol can cause changes in sleep patterns. Also, while folklore says that drinking alcohol improves milk production, studies show that alcohol actually decreases milk production and that the presence of alcohol in breast milk causes babies to drink about 20% less breast milk.
If you choose to drink, avoid breast-feeding until alcohol has completely cleared your breast milk. This typically takes two to three hours for 12 ounces (355 milliliters) of 5% beer, 5 ounces (148 milliliters) of 11% wine or 1.5 ounces (44 milliliters) of 40% liquor, depending on your body weight. If you plan to drink alcohol, consider having a drink just after breast-feeding so that the alcohol begins to clear your breast milk during the natural interval between breast-feeding sessions.
Pumping and dumping breast milk doesn't speed the elimination of alcohol from your body. However, if you'll be missing a breast-feeding session, pumping and dumping will help you maintain your milk supply and avoid engorgement.
Remember, breast-feeding is the optimal way to feed a newborn and is recommended until a baby is at least age 1. If you choose to drink, plan carefully to avoid exposing your baby to alcohol.