Injectable Fertility Medications: Gonadotropins for Ovarian Stimulation
Gonadotropins are powerful medications that can be administered to stimulate follicular development within the ovaries. There are two different types of gonadotropins, follicle stimulating hormone (FSH) and luteinizing hormone (LH). These hormones are naturally produced by the pituitary gland, a small structure that resides behind your nose at the base of the brain. Under normal circumstances, the pituitary gland makes FSH and LH in a specific sequence and in a specific amount that causes only one follicle to ultimately grow and ovulate in any given month. When these medications are given in pharmacologic doses, several follicles can develop and subsequently ovulate. These medications have been combined with intrauterine insemination (IUI) to produce very high pregnancy rates. As a result, this treatment has become a mainstay of therapy for a variety of different conditions causing infertility.
Initially, gonadotropin therapy combined with IUI was used as a treatment for patients who did not respond to clomiphene citrate. As pregnancy rates have increased, this therapy is now frequently recommended for a variety of other conditions as well, including treated endometriosis, male factor, cervical factor, and unexplained infertility.
In a typical gonadotropin cycle, we will schedule you to come in to the office for a baseline ultrasound examination on the first, second, or third day of your menstrual cycle. If the ultrasound confirms that there are no cysts within your ovaries, we will ask you to begin taking a single injection of gonadotropin daily. As these medications are powerful, we will monitor you closely with a combination of vaginal ultrasonography and blood estrogen levels every two to three days during the follicular maturation process. When ultrasound demonstrates that your largest follicles are mature (typically 19 to 20 mm in average diameter), a single injection of hCG or Ovidrel will be administered. This injection triggers the egg to actually come out of the follicle (“ovulation”). Intrauterine inseminations are performed on each of the next two days following the Ovidrel injection.
The side effects of gonadotropin therapy include bloating, cyst development, multiple pregnancy, and a very rare condition called ovarian hyperstimulation syndrome. While the typical chance for pregnancy is based on the patient’s age, a woman 35 years of age or younger should expect a pregnancy rate of 20-25% per cycle of gonadotropin/IUI therapy.
There are several different classes of gonadotropins. Some are made from a recombinant DNA technology while others come from human urine. At TFC, we prefer recombinant DNA produced gonadotropins (Gonal- F andFollistim®), as these products are over 99% pure. You can inject yourself subcutaneously (just underneath the skin) with a small needle, as these shots are relatively painless. The other class of drugs, urinary products such asMenopur® and Repronex®, are also effective at producing follicular development, ovulation, and pregnancy. They are, however, obtained from purified urine produced by postmenopausal women. Therefore, there are theoretic concerns about their safety, as they do contain small amounts of protein (albeit sterilized protein) from other humans.
In summary, gonadotropin therapy combined with IUI offers many couples an outstanding chance for pregnancy at a fraction of the cost of a cycle of in vitro fertilization. Due to the risks of multiple pregnancy and hyperstimulation, we monitor our patients very closely, both to maximize the chance for pregnancy and to minimize the likelihood of side effects.