• Breast milk;
  • Leptin;
  • Newborn;
  • Weight gain


Aim: To investigate whether change in leptin content of breast milk during lactation acts on neonatal body weight gain.

Methods: In total 15 lactating women and their 15 term infants were involved in the study. Breast milk and neonatal serum samples were obtained from the same women and their neonates on the 1st day and any day between the 21st and 30th days after birth. Breast milk and serum leptin concentrations were determined by radioimmunoassay. Anthropometric indexes of the infants were recorded.

Results: The study was completed with 15 multiparious mothers aged 19–37 years and their infants. The mean collection time of the first samples after birth was 6.07 ± 1.94 h. The leptin level in the mature milk was significantly higher than in the colostrum (p < 0.001). Neonatal weight and height were significantly increased on 21–30 lactation days compared to 1st day of lactation (p < 0.05 and p < 0.001, respectively). The leptin concentration in the mature milk was negatively correlated with delta BMI (r =−0.53; p < 0.05). The delta breast milk leptin concentration was also found to be inversely correlated with delta BMI (r =−0.529; p < 0.05).

Conclusion: The results of this study have suggested that change in the leptin content of breast milk during lactation might play a role in the regulation of weight gain in healthy neonates.