Follicle Stimulating Hormone (FSH)
Like hMG, this drug is also derived from the urine of post-menopausal women (often nuns for ease of collection), and is given as an injection. Because the demand for it has been so high, there is also a genetically engineered form of FSH called recombinant human FSH. This medication does not really contain any LH and it can only be used by women who have adequate amounts of their own LH. It can be useful for women with polycystic ovarian syndrome (PCOS) because they tend to have high LH levels. It is possible to have a kit with this drug so that you can self-inject under the skin.
Bromocriptine
This drug is used if a woman secretes too much prolactin from the pituitary gland. Prolactin is the same hormone that stimulates breast milk and can stop ovulation and periods because it inhibits the release of FSH and LH. Excess prolactin can also be caused by a benign tumour within the pituitary gland so cases of high prolactin should be investigated fully. This drug is given in tablet form and can cause nausea, headache, dizziness, fainting and decreased blood pressure. Carbergoline is a newer drug for treating high levels of prolactin and it has fewer side-effects than bromocriptine.
Gonadotropin Releasing Hormone (GnRH)
GnRH is released naturally from the hypothalamus in the brain in small amounts every 90 minutes. This pulsing effect releases both FSH and LH from the pituitary gland. If the patient has a deficiency of GnRH then FSH and LH will not be secreted. When women lose large amounts of weight quickly (or if they have anorexia) the secretion of GnRH decreases, stopping ovulation and causing infertility. Because GnRH works in a pulsing rhythm, it has to be given in the same way to mimic the natural cycle. This means that the woman has to wear an automatic pump 24 hours a day; at intervals of 90 minutes the pump releases the GnRH which goes to a needle inserted under the skin. Side-effects can include headaches and nausea. And there is a slight risk of multiple pregnancy.
Gonadotropin Releasing Hormone (GnRH) Analogues
These are synthetic hormones that work in a very different way to GnRH. They can be given as an injection or as a nasal spray. Because it gives a constant dose of synthetic GnRH to the hypothalamus, instead of the pulsed GnRH (above), the pituitary stops releasing both FSH and LH. This in turn stops the production of hormones by the ovaries, so oestrogen levels drop. These analogues are often used in IVF treatments because they are believed to result in more mature eggs (by stopping the release of LH which could cause the follicles to release eggs before they were ready). Side-effects include headaches, mood swings, vaginal dryness and insomnia. These analogues are often used to treat endometriosis and fibroids.
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