Growth hormone stimulates galactopoiesis in healthy lactating women

Abstract

Sixteen normally lactating women underwent a double-blind randomized placebo-controlled trial of recombinant human growth hormone (hGH) to assess the effect of hGH on milk production in early lactation. Milk volumes were measured by test weighing procedures of the infants and removal of residual milk on a control day and after 7 days of treatment with recombinant hGH (0.1 IU·kg−1 body weight·d−1) or placebo treatment. Although all women were lactating normally before the study commenced, milk volume in 8 hGH treated mothers was increased (p<0.02) by 18.5±1.4% (mean±sem) compared to 11.6±2.0% in the placebo-treated group (N=8). No adverse effects were seen with hGH treatment and no major changes noted in milk constituents. The hGH concentrations in milk were low and did not change with therapy. Plasma concentrations of IGF-1 increased significantly within 24 h of hGH treatment and increased further towards the end of the trial to values of 2.6-fold above the pretreatment values. The concentration of IGF-1 in milk was approximately 100-fold lower than those observed in plasma and could only be reliably measured after size exclusion chromatography to remove the interfering influence of IGF binding proteins in the radioimmunoassay. All women treated with hGH showed a small increase in milk IGF-1 concentrations but the values remained within the range of values observed in women receiving the placebo treatment (1.2–4.4 μg/l). Growth hormone treatment increased milk volume in normal lactating women during early lactation. This galactopoietic effect of hGH treatment was accompanied by an increase in plasma IGF-1 with no major change in milk constituents and no side effects to the mothers and the babies. Since our results show that a moderate dose of hGH can increase milk volume in healthy, normally lactating women during peak lactation, we suggest that hGH therapy should be considered in future trials for treatment of lactational insufficiency or lactational failure.