Human Chorionic Gonadotropin (HCG)
HCG (Profasi, Pregnyl ) induces the same effect that your natural LH surge provides --- the maturation and ovulation of the mature egg or eggs from the ovary.
It is administered when the follicles have reached the adequate size (18 - 20 mm) and the estradiol level is sufficient.
Appropriately-timed HCG injection ensures ovulation approximately 36-38 hours later, and enables perfectly timed intercourse or insemination.
HCG is also used during in vitro fertilization (IVF) cycles to mature the eggs prior to egg retrieval, which is then performed 35 hours after the HCG injection.