When your milk comes in — two to four days after birth — and replaces the colostrum, you will know it. Your normally squishy breasts will get bigger than you ever imagined possible and may seem as hard as rocks. For some women, this transition from colostrum to milk can be rough, but at least it doesn't last long (typically just a day). You may feel like you are going from a size C to a size ZZ.
How do I know if my baby is eating enough?
Rest assured, he's fine if: he nurses eight to ten times a day; he has six to eight wet diapers a day after the first week; your baby's poop resembles Dijon mustard mixed with cottage cheese by the fifth day; he seems healthy and alert; he gains weight after the first week; and your breasts feel full before each feeding and softer afterward.
Fetch your baby and start nursing because the longer you wait, the more your breasts will hurt. If your breasts are too hard for your baby to latch on to, put a warm washcloth on them for a few minutes or take a shower. You can also massage your milk glands toward your nipple and squeeze out a little milk. If you are still uncomfortable after your baby nurses, put ice on your breasts for a few minutes, or tuck a cold cabbage leaf into your bra. While this may seem like odd advice, cabbage, possibly because of its sulfur content, draws out the excess fluid to reduce swelling and the cold feels good.
Think about what you are going to name the act of breastfeeding because, sooner than you think, your baby will be using that word. (It may sound cute to ask your infant if he wants “tittie,” but having a toddler scream “tittie” in a crowded grocery store is not that cute.) Some options other parents have used include: num-nums, boobie, the boob, ba, snack, lunch, nurse, nurch, drink, dahda, mimi, mother's milk, or bup.
Now when your baby begins to feed, you may feel a tingling or burning sensation a moment before milk begins to leak from your breasts. This is the let-down reflex, caused by the release of oxytocin, the hormone that triggers contractions in the muscles surrounding the milk-producing cells to squeeze the milk into the milk ducts. (You don't need to be feeding a baby to trigger this reflex. It can happen during sex, when you see a picture of a baby, if you hear a baby cry, and sometimes for no apparent reason.) If you don't feel it, you'll still know milk is flowing because your baby will start gulping. (He may also pull away for a moment if the milk is spraying too fast.)