Luteinizing Hormone in Controlled Ovarian Stimulation

The role of follicle stimulating hormone (FSH) in assisted repro­ ductive technology is well understood, though there is still no published consensus on the need for exogenous luteinizing hormone (LH) in controlled ovarian stimulation. There is a dilemma regarding the usefulness of LH supplementation in controlled ovarian stimulation despite growing understanding of the LH and FSH interrelation and their effects on fertilization and implantation. This review revisits the physiological role of LH, LH receptors and the concept of LH therapeutic window. With the availability of LH activity from different sources, there is a need to understand the differences between recombinant human LH (r­HLH), human menopausal gonadotropin and human chorionic gonadotropin (hCG). It has been observed that adjuvant r­HLH provides precise control over the dose of LH bioactivity administered to target the therapeutic window. This review discusses about the various patient subgroups that may benefit from LH supplementation. The use of r-HLH is recom­ mended in women with poor response in a previous cycle or suboptimal follicular growth in an ongoing ovarian stimulation cycle by day 6 to 8 of stimulation. Exogenous LH administra­ tion should also be considered in women at risk of suboptimal response, specifically age > 35 years and women treated with GnRH analogues (agonists or antagonists) during ovarian stimulation causing over suppression of endogenous LH and FSH pituitary secretion. Further research is needed to identify LH polymorphisms, adequate dosing, cost efficacy, need for rLH and hCG supplementation in different patient profiles for maximum benefit during controlled ovarian stimulating (COS).