Luteinizing hormone and human chorionic gonadotropin: a review of their varied clinical applications in assisted reproductive technology.

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) are often viewed as interchangeable from a functional standpoint because they are highly homologous members of the same glycoprotein hormone family that share a common α-subunit and receptor. However, technological advances yielding highly purified and recombinant gonadotropin preparations have revealed that LH and hCG fulfill different roles, both endogenously and when administered exogenously. These differences are becoming more apparent as the individual hormones are incorporated into the treatment of infertility - a therapeutic area that is continually advancing with the introduction of new agents and emerging clinical trial data. This review examines the unique attributes of LH and hCG that drive their distinctive applications in the treatment of female infertility.