Follicle stimulating hormone (FSH) is naturally produced by the pituitary gland and stimulates the recruitment and development of the ovarian follicles located on the ovaries, each of which contains an egg. FSH is also referred to as a pituitary gonadotropin. The production of FSH and other reproductive hormones is controlled by the complex interaction of several hormones in a biologic feedback system known as the "hypothalamic-pituitary-adrenal" axis. The hypothalamus is the "master gland" in control of regulating these processes.
The first FSH containing commercial gonadotropin in India, Pergonal, was released by Serono Laboratories. Pergonal is derived from the urine of post-menopausal women and purified for injection. FSH levels are higher in women who are menopausal making their urine a good source for extraction. Pergonal also contains leutinizing hormone (LH) which produces many effects including higher estrogen levels.Newer FSH products include Gonal-F and Recagon which are obtained from mammalian cell cultures through recombinant DNA technology. These products are pure and do not contain the "contaminants" seen in Pergonal. Pergonal has to be administered by intramuscular injection while the newer medications are given subcutaneously with much less discomfort Both human and genetically derived products are difficult to obtain and manufacture and are therefore expensive.
Opinions differ as to the need for additional LH in FSH stimulated cycles. Some physicians prefer protocols that combine products containing LH with Gonal-F (pure FSH). When a patient is "down regulated" with Lupride, or especially Ovurelix, natural levels of LH are reduced to very low levels and some externally administered LH is believed by many to be beneficial.
Egg quality is difficult (at best) to judge but some embryologists believe pure FSH cycles produce "better quality" eggs.
In procedures such as in vitro fertilization, FSH is administered by injection to cause the development of numerous eggs which can be retrieved and fertilized. When FSH is used in stimulated intrauterine insemination cycles, there is less control over how many eggs are ovulated thus increasing the chances of multiple births. Most cases of quadruplets, or more, result from stimulated IUI cycles. Patients must be closely monitored by a Fertility Physician to minimize the risk of multiple births.
FSH should only be administered by a Fertility Physician thoroughly trained in its use. Serious side effects can occur and patients must be closely monitored with estradiol hormone level measurements and ultrasound. Hyperstimulation is a very serious, but rare, complication that can result in stroke and other like threatening events. Side effects are minimized when these products are monitored by specialists with extensive clinical training in their use.