Using Gonadotropins for Ovulation Induction
Gonadotropins are hormones that stimulate the gonads, which are the testes in men and the ovaries in women. Medications that are identical to these naturally occurring hormones are also referred to as gonadotropins. They work by bypassing the hypothalamus and pituitary gland and directly stimulating the development of follicles in the ovaries.
There are two main types of gonadotropin medications on the market: ones that contain follicle-stimulating hormone (FSH) alone and ones that contain FSH in combination with luteinizing hormone (LH). Products that contain the combination of FSH and LH are known as human menopausal gonadotropins (hMG).
All of these medicines are given as an injection, so they're not quite as easy to take as clomiphene
. The injection is administered either just beneath the skin (a subcutaneous injection) or into a muscle (an intramuscular injection), depending on which particular medicine you are using. Either way, you can be taught how to give yourself the injections at home.
Several different FSH medications are available. Brand names include Gonal-f® (follitropin alfa), Follistim® AQ (follitropin beta), and Bravelle® (urofollitropin). Bravelle is extracted from the urine of postmenopausal women, while Gonal-f and Follistim are made with a technique known as recombinant DNA technology. These medicines are all expected to work equally well.
There are also a couple of hMG medicines available. Brand names include Repronex® and Menopur® (menotropins). Both are obtained from the urine of postmenopausal women. HMG is expected to work as well as FSH for ovulation induction. However, FSH may be less likely to cause a side effect known as ovarian hyperstimulation syndrome.
Human chorionic gonadotropin (hCG) is another medication you'll likely become familiar with if you're using fertility drugs
. It's given to trigger ovulation once the follicles have matured after using FHS, hMG, or clomiphene. Brand names of hCG include Novarel®
(chorionic gonadotropin), which are extracted from the urine of pregnant women, and Ovidrel®
(choriogonadotropin alfa), which is made with recombinant DNA technology.
When They're Used
Gonadotropins are often the next fertility drug recommended after a woman fails clomiphene treatment. Because they are identical to naturally occurring reproductive hormones, they're usually a first-line treatment for women who don't ovulate because their pituitary gland doesn't release enough FSH or LH. Gonadotropins are also used to stimulate the development of multiple follicles in preparation for fertility treatments, such as in vitro fertilization.
How They're Taken
You'll usually begin treatment two to three days after starting your period. The medication is then injected every day for 7 to 12 days, though women who don't respond right away might need to use it for more than 12 days in a row.
Doses of gonadotropins need to be individualized for each woman, with the goal of finding the lowest dose that will lead to successful ovulation. Higher amounts are more likely to cause multiple births, such as twins or triplets.
Most of the time, a "step-up" approach is used, where doses are started low and then increased if the ovaries don't respond. However, some healthcare providers may start with higher doses and slowly decrease the amount. This "step-down" dosing has fallen out of favor, though, since it increases the risk for a potentially serious side effect known as ovarian hyperstimulation syndrome.
You'll need close monitoring during gonadotropin treatment so your healthcare provider can adjust your dose based on how you respond to the medicine. Your healthcare provider will examine your ovaries using an ultrasound every two to three days to monitor the growth of the follicles. Blood tests are used to measure the amount of estrogen in your blood.
When one or more follicles have matured, you will be given an injection of hCG. This hormone acts in the same way as LH, triggering the ovaries to release an egg (ovulation). You should plan on having sexual intercourse or intrauterine insemination 36 hours later, since you'll likely ovulate 36 hours after hCG is given.
If during monitoring your healthcare provider discovers that too many follicles have developed, you may need to skip the hCG injection for the time being and use birth control to prevent pregnancy. Although this may feel quite frustrating, it is necessary to help prevent ovarian hyperstimulation syndrome and multiple births, such as twins or triplets.
Are Gonadotropins Effective?
Starting gonadotropins at a low dose and slowly stepping up the dose until the ovaries respond has been reported to cause ovulation in 72 percent of women and pregnancy in 45 percent. Gonadotropins have also been reported to cause pregnancy in 71 percent of women who used the medications after clomiphene failed to work.
Bothersome side effects include headache
, breast tenderness, nausea, stomach pain or bloating, and mood swings. You might also have some redness or swelling at the site of your injection.
Gonadotropins can also cause an extremely serious side effect known as ovarian hyperstimulation syndrome. When this occurs, the ovaries enlarge and become painful. The condition can become severe enough that treatment in a hospital is necessary. By closely monitoring how your ovaries are responding to treatment, your healthcare provider will be able to significantly reduce the likelihood that you'll develop ovarian hyperstimulation syndrome.
The risk for multiple births is higher with gonadotropins than with clomiphene. It's estimated that 15 percent to 30 percent of women who use gonadotropins will become pregnant with twins, triplets, or more.