Why is growth hormone underutilized for our most difficult IVF couples?

Why is growth hormone underutilized for our most difficult IVF couples?
In this issue of Fertility and Sterility, Regan et al. (1) present research findings on granulosa cell (GC) receptor density for growth hormone (GH), FSH, bone morphogenetic protein receptor 1B (BMPR1B), and LH in women with varying age and ovarian reserve undergoing in vitro fertilization (IVF). The authors found that GH receptor density was reduced in the poorer responders, and that GH receptor density increased with age in normal responders but not in poor responders. In their subjects aged 39–45 years with antral follicle counts (AFCs) of ≤8, GH treatment was associated with higher densities of all four receptors.
Source: fertstert.org