Lupron, Ganirelix, and Cetrotide are used extensively in assisted reproductive technology cycles. During an IVF cycle, the fertility specialist must time the stimulation for maximum follicular maturation and insure that ovulation does not occur prior to egg retrieval.
Lupron is a GnRH agonist and it impedes the production of GnRH at the hypothalamus. When GnRH is suppressed, the body’s production of natural FSH by the pituitary slows and external FSH must be administered to stimulate follicular development.
These drugs are given according to individualized patient specific protocols. Sometimes Lupron is started during the cycle prior to stimulation to take advantage of a “rebound or flare” effect seen with these drugs.
Since Lupron suppresses GnRH, it also reduces estrogen production. Endometrial tissue is dependent upon estrogen for growth and support and this is why Lupron is effective in treating endometriosis. It is also one reason progesterone is usually administered in ART cycles.
As long as Lupron is administered, the LH surge necessary to induce ovulation cannot occur. This allows the fertility specialist to extend the stimulation cycle, if necessary, until the eggs within the ovarian follicles reach maturity.
Once the follicles are ready for retrieval, an injection of human chorionic gonadotropin (hCG), or LH, is given initiating the final stages of follicular development and ovulation occurs 34-36 hours later. The body responds to a surge in hCG in the same manner as natural LH. The eggs are retrieved prior to ovulation.
Ganirelix and Cetrotide produce the same physiologic effects of GnRH suppression as Lupron. However, these products actually block GnRH at the pituitary producing a “more complete” suppression. Because of this blocking effect, more FSH is sometimes required for Ganirelix/Cetrotide suppressed cycles. Also, these products can be given for a shorter time than Lupron increasing patient convenience.