In vitro fertilisation. A review of drug therapy and clinical management.

Since the first in vitro fertilisation (IVF) pregnancy was delivered in 1978, this procedure has resulted in thousands of pregnancies and opened a vast new frontier of research and treatment for the infertile couple. Pregnancy rates with IVF improve as the number of high quality embryos available for transfer increases; therefore, ovarian stimulation agents to produce multiple oocysts for IVF are advantageous. Clomifene (clomiphene citrate), human menopausal gonadotrophin (hMG; menotropins), and subsequent generations of products are commonly used as stimulation agents. In conjunction with the stimulation agents, gonadotrophin-releasing hormone (GnRH) agonists and human chorionic gonadotrophin (hCG) serve as adjuvants for successful control of all events in the induction process. Clomifene, an estrogen agonists/antagonist, occupies the estrogen receptor for a longer period of time than estrogen (weeks versus hours). Because this signal is interpreted as low estrogen, GnRH is released, which produces a rise in circulating levels of follicle-stimulating hormone (FSH) and luteinising hormone (LH) and subsequent ovarian follicular development. Menotropins is collected by passing urine from menopausal donors over a Sepharose column, followed by removal of high molecular weight impurities by chromatography. The mixture of FSH and LH is biologically standardised. This product stimulates multiple ovarian follicular development. Urofollitrophin is produced using antibodies to hCG anchored to a separation column. LH then can be excluded from the eluate by binding to the hCG antibodies (LH immunoaffinity column). Highly purified FSH is obtained by passing menopausal urine over a column with monoclonal antibodies to FSH. The isolated FSH is then eluted from the column by a highly basic solution and crystallised. This product delivers FSH at a 90% purity and can be administered subcutaneously rather than intramuscularly. Dosage is standardised on a mg/kg basis. Recombinant human FSH is completely free of LH and offers the advantages of better batch consistency, greater purity, and absence of any human contaminants. It may be given both subcutaneously and intravenously. Genetically engineered FSH combines portions of the native protein with another protein (hCG) which enhances its potency and extends the half-life compared with wild-type FSH. Short, medium and ultra-long activity analogues of genetically engineered FSH may be used to tailor stimulation protocols in various clinical situations. Growth hormone is an adjuvant to ovarian stimulation which results in a decreased number of ampoules of menotropins being required to achieve ovulation in poor responders. Ovulation triggers include both hCG and GnRH agonists. Progesterone supplementation is generally used in the luteal phase of the IVF cycle and is administered by intramuscular injection or vaginal suppository. It appears that conscious sedation with midazolam, pethidine (meperidine) and fentanyl is nontoxic for oocyte recovery. If full anaesthesia is required for gamete intrafallopian tube transfer (GIFT) or zygote intrafallopian tube transfer (ZIFT), balanced anaesthesia with nitrous oxide and an opioid appears to be the most appealing option. Appropriate information on the clinical use of the drugs used in IVF greatly reduces patient stress associated with the complex multidrug regimens associated with the procedure.