Follicle Stimulating Hormone

FSH and HPA? What's That?

The pituitary gland, under the influence of gonadotropin releasing hormone, or GnRH, produces several hormones; among them is follicle stimulating hormone (FSH).  Normally, FSH levels are affected by their relationship to estrogen and other hormones in a woman's body.  The pituitary gland is part of the HPA, or hypothalamic-adrenal-pituitary axis and receives the GnRH from the hypothalamus.  The hypothalamus is something like a thermostat as it monitors the levels of hormones, such as FSH and luteinizing hormone in the body and also balances them.  An imbalance in hormones can lead to infertility, so injections of hormones are usually the first line of treatment for many women trying to conceive.

What Does FSH Do?

Follicle stimulating hormone directly stimulates the recruiting and stimulation of follicles, or in other words, egg production.  If a woman is having in vitro fertilization, then it is necessary for her to produce a number of eggs since some eggs do not mature and cannot be fertilized.  When FSH is used to induce ovulation, the woman is carefully monitored by ultrasound, physical examination and estradiol measurement.  Certain drugs which control the time of ovulation are given as well.  Only a professional trained in the use of FSH should administer the hormone.  Serious side effects may result if the process is not monitored carefully and levels adjusted appropriately.  The most publicized result of improperly monitored administration of FSH is high order multiple births.

A "Natural" Product

Initially, FSH was considered a natural product as it was derived and purified from the urine of post-menopausal women.  The down side was that because they were produced from human sources, they also contained luteinizing hormone (LH), considered an impurity.  Administration of the product was via intramuscular injection and it was very painful.  Recent products are the result of genetic recombining technology and these modified FSH products can be given subcutaneously under the skin because they are pure.  Gonal-F and Follistim are two of the more recognizable products.  Other products of human derivation which can be given subcutaneously are Bravelle and Menopur. 

Careful Monitoring A Must

Medical professionals are varied in their opinions of protocols.  Some believe that the inclusion of LH in FSH stimulated cycles cause a better stimulation for some women while others do not have the same view.  Often reproductive endocrinologists use a mix of protocols to assist in the fertility process.  The important factor in the use of FSH is monitoring by the specialist.  The responsibility to ensure doses are correct to enhance follicular development and timing of ovulation is critical when using FSH as a means of addressing infertility.