Breast milk production begins during pregnancy with the creation of colostrum, the first milk, which starts developing around 12 to 18 weeks of pregnancy. After birth, colostrum is available for the baby to consume right away. Typically, breast milk "comes in" or transitions from colostrum to transitional milk about 2 to 5 days after giving birth. Transitional milk is creamier and higher in protein than colostrum. Then, around 10 to 14 days after birth, mature milk starts to be produced, which continues as the baby grows. Signs that your milk has come in include breasts feeling fuller, firmer, heavier, sometimes warm or tingly, and possibly leaking milk between feeds. If it's not the first child, milk may come in sooner due to a kind of "memory" in the mammary glands. Even if milk takes a bit longer to come in, this can be normal, but if delayed significantly, consulting a healthcare professional or lactation consultant is recommended to ensure the baby is getting enough nutrition. In summary:
- Colostrum is produced during pregnancy and immediately after birth.
- Transitional milk typically arrives 2 to 5 days after birth.
- Mature milk usually comes in around 10 to 14 days after birth.
- Breast changes include engorgement and fullness when milk comes in.
- Milk may come in sooner with subsequent children.
