the best way to answer. would be to measure your baby's weight. in the first month infants are expected to gain 0. 5 to 1 ounces per day. in terms of increasing your milk supply the best thing to do is to feed/pump more often. your milk production works on a supply/demand relationship. the more often you feed your baby (or the more often you pump) the more milk your body will produce. there is nothing wrong with supplementing with formula but if your baby feeds less often as a result you may find that it may ultimately restrict your supply.
my 1 month old baby doesn't seem to be satisfied when i breastfeed him. can i supplement some feedings with formula?