When you’re pregnant, breast tissue for making milk increases, accounting for the size increase you experience during that time. On day 3-4 after birth when your milk transitions from colostrum to mature milk, your breasts engorge. This means extra blood (hello veins) and fluid fill the breast to support making milk. This additional blood and fluid are what help make you aware of that full breast feeling before each feeding. Your uterus doesn’t tell your breasts how many babies were born, so the body is prepared to make milk for 1, 2, or even 3 babies and often initially makes more milk than is needed.
Around 6-8 weeks, your hormones shift and the extra blood and fluid in your breasts go away (not your milk supply decreasing). You may no longer feel that full/empty sensation between feeds, but still be able to see lots of milk, because your body knows baby is on a full milk diet and going through multiple back to back growth spurts. You may occasionally engorge if you go too long between feedings or if you skip a pump session.
Between 11-14 weeks, your body has finally figured out how many babies it is feeding based on how often the breast is emptied. Your breasts will go back to their prepregnancy size while still making just enough milk for baby. Congratulations on your mom boobs. They no longer feel full/empty, making them feel like pancakes and leaking often slows or stops. You have not lost your milk supply, your body is more efficient at making milk and will consistently make what is routinely emptied. You are still maintaining a full supply as long as you’re continuing to feed on demand or (routinely pump).
Don’t be alarmed when these changes happen. This is the normal process that every body will go through