What Facts Should I Know about Fertility Drug Injections?
Women undergoing infertility treatment are all too familiar with the need to administer injections, whether subcutaneous (beneath the skin) or intramuscular. Although the commonly used fertility drug clomiphene (Clomid) is taken in pill form, a great many of the drugs required for women being treated for infertility necessitate getting a shot- typically, many shots – over a period of days to weeks. Depending upon her precise diagnosis and medical history, a woman may take one or several of these injectable fertility treatments.
The injectable drugs for infertility are hormonal treatments, all designed to regulate and stimulate the production of hormones or to trigger ovulation. There are subtle differences in the drugs and their mechanisms of action, although they are all used to promote fertility in some way.
What Are the 5 Most Common Injectable Fertility Drugs?
- hMG, or human menopausal gonadotropin (Pergonal, Repronex, and Metrodin): This drug is made up of two human hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Gonadotropins are commonly administered to women undergoing assisted reproduction technology treatments with the goal of stimulating the ovaries to produce multiple follicles (eggs) during one cycle. FSH and LH are the hormones that normally regulate the ovarian cycle and stimulate egg development and ovulation, and injections of this drug typically are given daily for 7 to 12 days in the first half of the menstrual cycle.
- FSH, or follicle stimulating hormone, may also be given on its own for the same purpose and in a similar manner as hMG. Brand names for FSH include Follistim, Fertinex, Bravelle, Menopur, and Gonal-F.
- Human chorionic gonadotropin, or hCG (Pregnyl, Novarel, Ovidrel, and Profasi) is a hormone used to trigger release of the eggs from the follicles (ovulation). This is given in combination with other fertility drugs that stimulate follicle production and is administered at a precise time during the menstrual cycle, based upon the results of blood tests and ultrasound examinations. This is the same hormone that is produced by placenta during pregnancy and is measured in pregnancy tests.
- Gonadotropin Releasing Hormone Agonists, or GnRH agonists (Lupron, Zoladex, and Synarel) work by shutting down the body's production of ovarian hormones such as FSH and LH, lowering the body's estrogen levels. Normally in the body, GnRH is produced by the pituitary gland and stimulates the ovaries to produce hormones. When GnRH agonist is taken as a medication, there is an initial increase in hormone production and then a decline as the body senses that too much hormone is being made. Shutting down the normal hormone production by the ovaries allows for the precise control of egg development during a fertility treatment cycle. For example, a woman undergoing IVF may start taking this drug in the second half of her menstrual cycle, prior to the cycle in which she will attempt IVF. After the body's natural hormone production is shut down, gonadotropin drugs (see above) will be given to stimulate follicle production. Another advantage of GnRH agonists is that the body's natural production of LH, which triggers ovulation, is shut off, meaning that ovulation cannot occur prematurely and will not occur until the hCG injection (see above) is given.
- Gonadotropin Releasing Hormone Antagonist or GnRH antagonists (Antagon, Ganirelix, and Cetrotide) have a similar effect as GnRH agonists, but rather than initially stimulating and then down-regulating ovarian hormone production, GnRH antagonists work by immediately blocking the release of ovarian hormones. Typically, fewer injections of GnRH antagonists are required because of their stronger effect in reducing ovarian hormone production.