In plain words
Lactogenesis II is the stage when full milk production starts after birth. It begins after the placenta is delivered, when the hormone progesterone falls quickly. Other hormones, including , are still present, and together they signal the breast to make much more milk. The change usually shows up between about 30 and 72 hours after birth. Many mothers call it the milk coming in. Breasts often feel fuller, warmer, and heavier, and the milk shifts from thick, yellow to a thinner, whiter milk. The change can come later for some people, including after a long labor, a , diabetes, obesity, retained placental tissue, or significant blood loss. Milk removal in these first days is part of how supply is set. If the change seems late, talk with your provider or a .
The deeper version
begins with the withdrawal of progesterone after placental delivery, in the presence of prolactin, insulin, and cortisol. This closes between lactocytes and initiates copious synthesis of lactose, casein, and alpha-lactalbumin. Clinically, onset is recognized by maternal breast fullness and by a sharp rise in milk volume, typically between about 30 and 72 hours postpartum, with falling sodium and protein and rising lactose. Dewey and colleagues (2003) reported that delayed onset, beyond 72 hours, was associated with risk factors including cesarean birth and maternal obesity, and with greater neonatal weight loss. Delayed onset is also associated with early and shorter breastfeeding duration. The controversy is whether early supplementation causes delayed onset, or whether both reflect a shared underlying cause.
Where it comes up
- When your milk comes inFeeding Your Baby
- Colostrum and the first days before milk comes inFeeding Your Baby
- How breastfeeding works: supply and demandFeeding Your Baby
- Engorgement when milk comes inPostpartum: Your Body
- Low milk supply: real, perceived, and what helpsFeeding Your Baby
What mothers here say about lactogenesis II
No one has posted under this term yet.
Sources
- Dewey KG et al. — Risk factors for suboptimal infant breastfeeding behavior, delayed onset of lactation, and excess neonatal weight loss. Pediatrics, 2003
- Neville MC, Morton J — Physiology and endocrine changes underlying human lactogenesis II. Journal of Nutrition, 2001