In the early months, babies should gain four to seven ounces per week. If your baby’s weight gain is slower than average, there may be a medical or physical reason. So before you make the move to formula, I encourage you to make an appointment with a lactation consultant, who can help ensure your baby is latching properly. Not latching deeply enough is a very common problem. If the baby is only latching on the tip of the nipple, he won’t get as much milk and milk supply will not be stimulated.
Hang in there and seek professional help. Breastfeeding creates a wonderful bond between mother and baby, and using outside resources and support is part of the partnership.