Fertility Medications- FSH

Gonadotropins (pure FSH and mixed FSH/LH products):
(Gonal-F, Follistim, Menopur, Repronex, Bravelle)

Gonadotropins (pure FSH and mixtures of FSH and LH hormones) are the primary injectable fertility medications. For simplicity we will refer to all gonadotropins (pure and mixtures) as FSH.

Follicle stimulating hormone (FSH) is a fertility medication used to directly simulate the ovaries. It occurs naturally and is released by the pituitary gland when it is stimulated by gonadotropin releasing hormone (GnRH). GnRH is produced by the hypothalamus which regulates many hormones in a system called the hypothalamic-pituitary-adrenal axis. This is discussed in detail in our section on ovulation.

FSH was first marketed as Pergonal, which was derived from the urine of post menopausal women (naturally derived). Since it was a natural product, it contained some "impurities" notably luteinizing hormone (LH). However, many specialists believe that the LH is needed in some patients.

Urinary FSH/LH was purified further and marketed as Metrodin,and subsequently highly purified and promoted as Fertinex by Serono Laboratories. The next step was the release of Gonal-F and Follistim which are pure FSH products. These products are a result of genetic recombinant technology and exactly mimic the bodies own FSH. Other LH containing FSH preparations are available as Repronex and Menopur.

FSH's effect on the ovaries is much more pronounced than products such as Clomid and Letrozole. It is used primarily in assisted reproductive technologies (IVF) cycles and controlled ovarian hyperstimulated intrauterine (IUI) cycles.

When FSH is used in IUI cycles the patient must be carefully monitored to prevent ovarian hyperstimulation syndrome (OHSS) and high order multiple births. FSH stimulates the ovaries to develop numerous eggs that can be released simultaneously at ovulation. Many instances of quadruplets (and more) are the result of IUI cycles administered by non fertility specialists.

FSH is used in IVF cycles to cause the development and maturation of multiple eggs which will be withdrawn from the follicles at retrieval. High order multiple births are not common in IVF cycles because the physician controls how many embryos are placed in the uterus.

FSH is administered according to patient specific treatment protocols. IVF patients receive Lupron or Antagon which dramatically reduces the internal production of FSH and LH, termedd down regulation.

FSH is administered by injection to cause follicular development and patients are closely monitored via transvaginal ultrasound and measurements of estradiol. The dosage of FSH is varied based upon each patient's response. Once the physician judges that the follicles are mature, an injection of human chorionic gonadotropin (hCG) is given and retrieval is scheduled 36 hours later.

FSH can produce serious side effects including ovarian hyperstimulation syndrome. It should always be administered by a reproductive endocrinologist with extensive clinical training in its use.

Organon, manufacturer of Follistim provides extensive information on infertility.