Breast milk retinol concentration in mothers of preterm newborns

- The transitional milk of preterm mothers has a different profile from that of full-term mothers;
- Probably, the preterm milk undergoes a physiological adaptation to compensate the lower placental transfer of retinol;
- Its important the adoption of interventions to prevent vitamin A deficiency in preterm infants.

BackgroundPreterm newborns have low vitamin A reserves at birth, which increases their risk of morbidity and mortality. In the absence of supplementation, breast milk is the only source of this nutrient for exclusively breastfed infants.AimsTo assess retinol concentration in preterm milk and the relationship between this retinol concentration and lactation phase, degree of prematurity, and maternal serum retinol level.Study designLongitudinal study.SubjectsFifty-eight preterm mothers.Outcome measuresColostrum (1-3 d), transitional (7-15 d), and mature human milk (30-55 d) samples were collected. Maternal blood was collected once at postpartum. Retinol level was measured using high-performance liquid chromatography.ResultsMilk retinol concentration was statistically different between lactation phases (p < 0.001): 2.84 ± 1.05 μmol/L in colostrum (58), 3.47 ± 1.28 μmol/L in transitional (58), and 2.03 ± 0.61 μmol/L in mature milk (30). No difference was found in milk retinol levels between groups with different degrees of prematurity (p > 0.05). Maternal serum retinol (1.82 ± 0.50 μmol/L) did not correlate with milk levels (p > 0.05).ConclusionsRetinol level in preterm milk seems to be independent of the degree of prematurity and maternal serum status. A significant increase in micronutrient levels in transitional milk was observed, which is likely to contribute to reserves in the premature liver.