Lactoferrin concentration in breast milk during the first postpartum year in Lima Norte, Peru

Lactoferrin (LF) is a glycoprotein with antimicrobial and immunomodulatory properties, present in breast milk and fundamental in infant protection. The objective was to describe the LF concentration during the first postpartum year in Lima Norte, Peru. A retrospective observational study was conducted based on a secondary analysis of 158 milk samples from 83 mothers: 39 from transitional milk (7-14 days) and 119 from mature milk (2-12 months). LF was quantified by ELISA. The median LF in transitional milk was 6.52 (IQR: 5.16-8.15) mg/mL and in mature milk 1.01 (IQR: 0.80-1.57) mg/mL. In the mature milk periods, the values were 3.33 mg/mL (2 months), 3.27 (3-5 months), 2.56 (6-7 months), and 2.08 (8-12 months). In the 22 mothers with paired samples, the mean concentration was 7.71 ± 2.27 mg/mL in transitional milk and 3.76 ± 1.06 mg/mL at 2 months. The absence of sufficient colostrum samples and the unequal sample availability limit the complete characterization of the trajectory during the first year. The results describe a decreasing pattern of LF concentration during the first year of lactation.