hCG:

Fertility

Human chorionic gonadotropin is extensively used parenterally as an ovulation inducer in lieu of luteinizing hormone. In the presence of one or more mature ovarian follicles, ovulation can be triggered by the administration of hCG. As ovulation will happen 24-36 hours after the injection of hCG, procedures can be scheduled to take advantage of this time sequence.[9] Thus, patients that undergo IVF, in general, receive hCG to trigger the ovulation process, but have their eggs retrieved at about 36 hours after injection, a few hours before the eggs actually would be released from the ovary.

As hCG supports the corpus luteum, administration of hCG is used in certain circumstances to enhance the production of progesterone.

In the male, hCG injections are used to stimulate the leydig cells to synthesize testosterone. The intratesticular testosterone is necessary for spermatogenesis from the sertoli cells. Typical uses for hCG in men include hypogonadism and fertility treatment.

During first few months of pregnancy, the transmission of HIV-1 from woman to fetus is extremely rare. It has been suggested that this is due to the high concentration of hCG, and that the beta-subunit of this protein is active against HIV-1.[10]

[link to en.wikipedia.org]