RESUMEN
OBJECTIVE: The transition from colostrum to mature breast milk during early puerperium is associated with significant concentration changes of numerous compounds. However, it is not known whether the free sugars, aminohexoses, and polyols are affected. Therefore, in this study, we aimed to determine their concentrations in human colostrum and milk during the first 10 days postpartum. METHODS: This prospective longitudinal study in a sample of normal consecutive obstetric patients was conducted as a collaboration between two academic centers-Polish and American. Participants were 13 women after uncomplicated pregnancy and delivery at term of a singleton, appropriate-for-gestational-age fetus. Lactose, galactose, glucose, mannose, galactosamine, glucosamine, glycerol, and myo-inositol concentrations were measured using high performance liquid chromatography. RESULTS: During the first 3 days postpartum, the concentrations of lactose and glucose increased significantly (P < 0.001), to steady-state values thereafter. In contrast, the concentrations of myo-inositol and glycerol decreased significantly (P < 0.001) over the first 4 days, to reach relatively low stable values. ANOVA analysis indicated that the postpartum day at which early changes ceased to be significantly different from their plateau values was Day 4. myo-Inositol concentrations were significantly higher (P = 0.022) in multiparas than in primiparas. CONCLUSIONS: The colostrum-to-milk transition is associated with significant changes in concentrations of free sugars and polyols, changes which are completed by the fourth postpartum day. Parity influences the concentrations of some compounds in the breast milk.