At what postpartum day does lactogenesis stage II (copious milk secretion) typically occur in most lactating mothers?

Explanation

## Timeline of Lactogenesis **Key Point:** Lactogenesis stage II (copious milk secretion) typically begins 24–72 hours after delivery, with most mothers experiencing the "milk coming in" between postpartum days 2–5. ### Three Stages of Lactation Onset | Stage | Timing | Characteristics | Milk Volume | |-------|--------|-----------------|-------------| | **Stage I (Colostrum)** | Pregnancy to ~5 days postpartum | Mammary development; colostrum production begins immediately after delivery | 10–100 mL/day | | **Stage II (Lactogenesis II)** | Days 2–5 postpartum (can extend to day 7) | Abrupt onset of copious milk secretion; breasts become full, warm, engorged | 500–900 mL/day by day 5 | | **Stage III (Galactopoiesis)** | Beyond day 7; continues throughout lactation | Maintenance of milk supply through suckling stimulus and prolactin | 800–1000+ mL/day | **High-Yield:** The **2–5 day window** is the classic timeframe for lactogenesis stage II. Delayed lactogenesis (beyond day 7) is associated with: - Cesarean delivery - Maternal obesity - Diabetes mellitus - Primiparity - Inadequate milk transfer **Clinical Pearl:** Early frequent suckling (within 1–2 hours of delivery) and skin-to-skin contact promote timely lactogenesis and prevent engorgement and mastitis. **Warning:** Mothers should be counseled that colostrum in the first 24–48 hours is **normal and sufficient** for the newborn; the transition to copious milk production takes a few more days. [cite:ACOG Committee Opinion 658; Williams Obstetrics 26e Ch 37]