Medical Health Encyclopedia

FSH. FSH stimulates the follicles directly and may be used with hCG to produce the LH and FSH surges that trigger ovulation. FSH is typically used alone for women who have taken clomiphene and failed. Such women often have polycystic ovaries, which is characterized by high LH and low FSH levels.

Urofollitropin (Metrodin, Fertinex, Bravelle) is a menotropin extracted from the urine of postmenopausal women and has been the standard FSH agent. Recombinant follicle-stimulating hormone (Puregon, Gonal-F, Follistim) is genetically developed form of the natural FSH. Therefore it has no risk for contaminants, such as urinary proteins or traces of LH, which can occur with menotropins. (Bravelle is a highly-purified menotropin and may be as effective as recombinant FSH.)

Human Chorionic Gonadotropin (hCG). Human chorionic gonadotropin or hCG is similar to luteinizing hormone and mimics the LH surge, which is to stimulate the follicle to release the egg. Standard hCG agents (APL, Follutein, Pregnyl, Profasi, Humegon) are derived from the urine of pregnant women. The recombinant (genetically developed) form of hCG (Ovridel) has fewer side effects at the injection site and its quality can be better controlled than the natural agents. It is generally used after hMG or FSH to stimulate the final maturation stages of the follicles. Ovulation, if it occurs, does so about 36 to 72 hours after administration.

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GnRH Analogs (Agonists or Antagonists). Gonadotropin-releasing hormone analogs (GnRH-a) can be either GnRH agonists or antagonists. They are synthetic agents that are similar to natural GnRH but have very different actions. While natural GnRH stimulate a surge in LH, these agents actually prevent the LH surge that occurs right before ovulation. This action helps prevent the premature release of the eggs before they can be harvested for assisted reproductive technologies.

• GnRH agonists include leuprolide (Lupron), nafarelin (Synarel), goserelin (Zoladex), and buserelin.
• GnRH antagonists include ganirelix (Antagon) and cetrorelix (Cetrotide). These are newer agents that are proving to simplify the procedure because of their quicker action compared to GnRH agonist. They appear to pose less of a risk for complications and side effects in the treatment process. It is not clear, however, if they offer any advantages in achieving pregnancies.