Changes in Human Milk Macronutrients and Risk Factors for Delayed Lactogenesis: A Prospective Cohort Study.

This article focuses on the timing of Lactogenesis II onset and its impact on human milk macronutrient composition within 72 hours postpartum in a Chinese population. The study found that delayed onset of Lactogenesis II (DOL II), defined as maternal perception of milk "coming in" after 72 hours postpartum, occurred in 23.6% of participants and was significantly associated with gestational diabetes mellitus (GDM), Cesarean delivery, and pre-pregnancy overweight/obesity. Notably, lactose concentrations in human milk were significantly lower in the DOL II group and in mothers with GDM during the first 24 to 48 hours postpartum, highlighting a critical window for monitoring lactose levels to identify subclinical lactation impairment. Protein and fat levels increased over time but showed less consistent differences between groups. The findings suggest that early lactose deficiency linked to GDM may contribute to delayed lactogenesis, underscoring the need for targeted clinical interventions during the initial 48 hours postpartum.