Follicle Stimulating Hormone (FSH)
Follicle stimulating hormone is produced by the pituitary gland and stimulates the recruitment and development of follicles located on the ovaries. Each follicle contains one egg.
FSH containing products are administered to stimulate the development of multiple eggs, usually in assisted reproductive technology cycles. FSH is often used in stimulated intrauterine insemination cycles.
When FSH is used in IVF cycles, products such as Lupron or Antagon are given to precisely control hormone levels and time ovulation. hCG is administered prior to retrieval to mimic the bodies natural ovulatory cycle.
The first FSH containing product, Pergonal, was derived from the urine of postmenopausal women. Since it is a urinary product it contains impurities such as luteinizing hormone (LH). Newer urinary derived products include Repronex and Bravelle, which has less than 2% LH. Some data indicate that excessive levels of LH can lead to diminished egg quality.
New genetic cell culture technology has enabled manufacturers to produce pure FSH identical to that produced by the body (Gonal-F, Follistim). Some physicians and embryologists believe that the pure products offer therapeutic advantages. The primary advantage of the urinary products is that they are less expensive. Gonal-F, Follistim, Bravelle, and Repronex can all be administered subcutaneously. If a woman has a low level of LH in her body, we use a product that contains some LH, such as Repronex. If her LH level is normal, we use a pure FSH product, such as Follistim.
FSH should only be administered by a reproductive endocrinologist thoroughly trained in its use. Cycles must be monitored via ultrasound, estradiol measurements, and clinical evaluation to insure that the follicles are developing properly, help prevent high order multiple births, and guard against potentially serious side effects such as hyperstimulation syndrome.
Dosages must be adjusted based upon each patient’s individual response. Injections are usually given once daily but, dependent upon patient response, may be given twice daily.
Reproductive endocrinologists undergo extensive advanced training in the management of stimulated cycles. Most of the high order multiple births (over 3) reported in the media are due to FSH stimulated IUI cycles administered by non-specialists.