Developments in drugs for ovarian stimulation.

Drugs for ovarian stimulation have been improved during the last decades. Initially gonadotrophins were extracted from human pituitary glands and urine; nowadays they are produced from transformed cell-lines. All three gonadotrophins--follicle stimulating hormone (FSH), luteinizing hormone (LH) and human chorionic gonadotrophin (hCG)--are now marketed as recombinant (r-) products. The near-100% pure FSH preparations might, in some situations, cause abnormally low LH levels and it is likely that the addition of LH may be beneficial in these situations. It is possible that r-LH will become available in sufficient dosages to replace hCG for ovulation induction and this may reduce the incidence of ovarian hyperstimulation syndrome due to its shorter half-life. In parallel to the development of gonadotrophin preparations, protocols for ovarian stimulation are now more comfortable for the patients, especially with the introduction of gonadotrophin receptor hormone (GnRH)-agonists in the early 1980s and, more recently, the introduction of GnRH-antagonists.