Effects of Recombinant Human Prolactin on Breast Milk Composition

OBJECTIVE: The objective of this study was to determine the impact of recombinant human prolactin (r-hPRL) on the nutritional and immunologic composition of breast milk. METHODS: We conducted 2 trials of r-hPRL treatment. In the first study, mothers with documented prolactin deficiency were given r-hPRL every 12 hours in a 28-day, open-label trial. In the second study, mothers with lactation insufficiency that developed while they were pumping breast milk for their preterm infants were given r-hPRL daily in a 7-day, double-blind, placebo-controlled trial. Breast milk characteristics were compared before and during 7 days of treatment. RESULTS: Among subjects treated with r-hPRL (N = 11), milk volumes (73 +/- 36 to 146 +/- 54 mL/day; P < .001) and milk lactose levels (155 +/- 15 to 184 +/- 8 mmol/L; P = .01) increased, whereas milk sodium levels decreased (12.1 +/- 2.0 to 8.3 +/- 0.5 mmol/L; P = .02). Milk calcium levels increased in subjects treated with r-hPRL twice daily (2.8 +/- 0.6 to 5.0 +/- 0.9 mmol/L; P = .03). Total neutral (1.5 +/- 0.3 to 2.5 +/- 0.4 g/L; P = .04) and acidic (33 +/- 4 to 60 +/- 6 mg/L; P = .02) oligosaccharide levels increased in r-hPRL-treated subjects, whereas total daily milk immunoglobulin A secretionwas unchanged. CONCLUSIONS: r-hPRL treatment increased milk volume and induced changes in milk composition similar to those that occur during normal lactogenesis. r-hPRL also increased antimicrobially active oligosaccharide concentrations. These effects were achieved for women with both prolactin deficiency and lactation insufficiency. Pediatrics 2011;127:e359-e366