No amount of alcohol is safe during pregnancy, but during lactation, there are certain guidelines which need to be followed. Age of infant is very important. If the newborn is less than 3 months of age, its brain and liver are very immature. Hence alcohol is very toxic for them and is metabolized with great difficulty. Infants older than 3 months can metabolize alcohol comparatively quicker.
Guidelines say that occasional use of alcohol i.e. 1-2 drinks does not usually harm the baby. But nevertheless, ingestion of alcohol should be minimized or avoided altogether. If taken then nursing should be delayed for 2 or more hours after alcohol intake to minimize the content of alcohol in breast milk. As soon as you recover neurologically from effects of alcohol, you can nurse your baby. Alcohol peaks in blood and breast milk ½-1 hour after consumption and it does not accumulate in milk. It leaves the milk as it leaves the blood. So when blood alcohol levels are low, levels in milk are also low. So there is no need to pump and throw away milk but adequate time interval between drinking and feeding should be there at least 2 hours.
Effects of alcohol on infant
Effects of alcohol on mothers
Though we advise against having alcohol while nursing but if once in a while you need to have a drink or two then have them after feeding the baby or while the baby is taking a long nap. You can pump and store milk beforehand or use the formula for 2-3 hours but till the baby is 3 months old, abstain if possible.