Different protocols exist for IVF-treatment. Check the website of the NVOG for more information. Most treatments start with the administration of a GnRH agonist such as buserelin or triptorelin in order to prevent a premature LH-surge.
Human chorionic gonadotropin (hCG), the pregnancy hormone, acts in a similar way as LH. HCG induces the last phase of follicle maturation and thus is used for the right timing of the ovulation. To prevent an eventual early LH surge and thus ovulation, GnRH agonists are applied in IVF-cycles.
Recombinant FSH is used to induce maturation of more ova.
HCG (the pregnancy hormone) is a gonadotropin produced by the placenta. II. Therapeutic gonadotropins are prepared from gonadotropins secreted in urine.
Extra info: Human chorionic gonadotropin (HCG) mainly acts like the hormone LH and is categorized in the class of gonadotropins. FSH, LH and HCG used to be obtained from female urine. Nowadays, these hormones are prepared by recombinant DNA techniques.