Get answers to your specific medical questions from UM Medical Center experts.
An in-depth report on the causes, diagnosis, treatment, and prevention of female infertility.
Pelvic inflammatory disease; Polycystic ovaries
Fertility drugs are often used alone as initial treatment to induce ovulation. If they fail as sole therapy, then they may be used with assisted reproductive procedures or artificial insemination to produce multiple eggs, a process called superovulation .
Clomiphene citrate (Clomid, Serophene) is usually the first fertility drug of choice for women with infrequent periods and long cycles. Unlike more potent drugs used in superovulation, clomiphene is gentler and works by blocking estrogen, which tricks the pituitary into producing FSH and LH. This boosts follicle growth and the release of the egg. Clomiphene can be taken orally, is relatively inexpensive, and the risk for multiple births (about 5%, mostly twins) is lower than with other drugs.
Women with the best chances for success with this drug are those with the following conditions:
Women with poorer chances to no chances with this drug have the following conditions:
One or two tablets are taken each day for 5 days, usually starting 2 - 5 days after the period starts. If successful, ovulation occurs about a week after the last pill has been taken. If ovulation does not occur, then a higher dose may be given for the next cycle. If this isn't successful, treatment may be prolonged or additional drugs may be added. Experts usually do not recommend more than 6 cycles.
The drug often reduces the amount and quality of cervical mucous and may cause thinning of the uterine lining. In such cases, other hormonal drugs may be given to restore thickness. Other side effects include ovarian cysts, hot flashes, nausea, headaches, weight gain, and fatigue. There is a 5% chance of having twins with this drug, and a slightly increased risk for miscarriage.
Superovulation, also called controlled ovarian stimulation, is generally used if clomiphene does not work. This approach is the direct administration of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), collectively called gonadotropins. The intent is to mimic the natural process leading to ovulation and produce multiple follicles. Superovulation is generally used in conjunction with assisted reproductive technologies.
Many of the drugs used in superovulation are either taken from natural sources (menotropins) or are genetically developed:
Human Menopausal Gonadotropins (hMG). HMG (Pergonal, Repronal, Metrodin) is a menotropin that contains both FSH and LH and is obtained from the urine of postmenopausal women. HMG must be self-administered as an injection. It is one of the potent ovulation drugs and is often used in assisted reproductive techniques. It may help stimulate fertility in women with ovarian dysfunction, endometriosis, and unexplained infertility. HMG is administered as a series of injections 2 - 3 days after the period starts. Injections are usually given for 7 - 12 days, but the time may be extended if ovulation does not occur. In such cases, an injection of human chorionic gonadotropin (hCG) may trigger ovulation.
FSH. FSH stimulates the follicles directly and may be used with hCG to produce the LH and FSH surges that trigger ovulation. FSH is typically used alone for women who have taken clomiphene and failed. Such women often have polycystic ovaries, which is characterized by high LH and low FSH levels.
Urofollitropin (Metrodin, Fertinex, Bravelle) is a menotropin extracted from the urine of postmenopausal women and has been the standard FSH drug. Recombinant follicle-stimulating hormone (Puregon, Gonal-F, Follistim) is genetically developed form of the natural FSH. Therefore it has no risk for contaminants, such as urinary proteins or traces of LH, which can occur with menotropins. (Bravelle is a highly-purified menotropin and may be as effective as recombinant FSH.)
Human Chorionic Gonadotropin (hCG). Human chorionic gonadotropin or hCG is similar to luteinizing hormone and mimics the LH surge, which is to stimulate the follicle to release the egg. Standard hCG drugs (APL, Follutein, Pregnyl, Profasi, Humegon) are derived from the urine of pregnant women. The recombinant (genetically developed) form of hCG (Ovridel) has fewer side effects at the injection site, and its quality can be better controlled than the natural drugs. It is generally used after hMG or FSH to stimulate the final maturation stages of the follicles. Ovulation, if it occurs, does so about 36 - 72 hours after administration.
GnRH Analogs (Agonists or Antagonists). Gonadotropin-releasing hormone analogs (GnRH-a) can be either GnRH agonists or antagonists. They are synthetic drugs that are similar to natural GnRH but have very different actions. While natural GnRH stimulates LH, these drugs actually prevent the LH and FSH surge that occurs right before ovulation. This action helps prevent the premature release of the eggs before they can be harvested for assisted reproductive technologies.
GnRH-a drugs are administered by injection or nasal spray. They increase the risk for ovarian cysts, but according to a 2000 study, they have no negative effect on pregnancy. They may increase the risk for ovarian cysts and cause menopause-like effects, including hot flashes, vaginal dryness, insomnia, and osteoporosis.
Women with endometriosis often have an especially difficult time getting pregnant. A 2006 review suggested that GnRH agonists may help women with endometriosis quadruple their chances of becoming pregnant when the drug is 3 – 6 months prior to in vitro fertilization (IVF) or intracysoplasmic sperm injection. [For more information, see In-Depth Report #74: Endometriosis.]
Multiple Births. Overproduction of follicles can lead to ovarian enlargement. This event increases the risk for multiple births. There is a 25% chance of multiple births (about 17% for twins and 8% for triplets and over).
Ovarian Hyperstimulation Syndrome. The most serious complication with superovulation is ovarian hyperstimulation syndrome (OHS), which is associated with the enlarged ovary (although the precise cause is unknown). This can result in dangerous fluid and electrolyte imbalances and endanger the liver and kidney. OHS is also associated with a higher risk for blood clots. In rare cases, it can be fatal. Symptoms include abdominal bloating, nausea, vomiting, and shortness of breath.
Bleeding and Rupture of Ovarian Cysts. Overproduction of follicles, if unchecked, may result in bleeding and rupture of ovarian cysts.
Cancer Concerns. There has been concern about an increased risk for ovarian and breast cancers in women taking fertility drugs, particularly clomiphene and human menopausal gonadotropins. In general, a strong body of evidence is finding no higher risk for either breast or ovarian cancer from the drugs themselves. Instead, such studies are suggesting that these cancers are caused by the same factors that contribute to the infertility itself.
Tamoxifen. Tamoxifen (Nolvadex) is a drug known as a selective estrogen-receptor modulators (SERM). It is used to prevent breast cancer in high-risk women. Studies suggest that it may equal clomiphene in its ability to induce ovulation. It may be especially useful when used along with IVF for preserving fertility in breast cancer patients. This drug is less expensive than clomiphene, but it poses some health hazards, including a risk for blood clots and uterine cancer.
Aromatase Inhibitors. Aromatase inhibitors block aromatase, an enzyme that is a major source of estrogen in many major body tissues. These drugs include anastrozole (Arimidex) and letrozole (Femara). These drugs are used for treating breast cancer and are being investigated for stimulating ovulation in infertile women. Although letrozole is not approved for treatment of infertility, it has become widely used for this purpose in recent years. Some experts were concerned that letrozole could increase the risk of birth defects. However, a major 2006 study indicated that letrozole does not increase risk to the fetus. The study compared the rate of birth defects among babies whose mothers conceived with letrozole and those who used clomiphene (the standard first-line fertility drug). Researchers found no differences in birth outcomes between the two groups.
Typical Regimen for Hyperstimulation and In Vitro FertilizationRegimens to induce ovulation vary widely according to individual need. A typical procedure, involving superovulation and in vitro fertilization (IVF) may be as follows:
|
Gentler Alternatives to SuperovulationNatural (Unstimulated) In Vitro Fertilization Cycles. An alternative to superovulation for some couples is natural IVF cycles. It allows multiple, consecutive cycles of treatment. Natural IVF is far less expensive than standard hyperstimulation methods and avoids their risks, including multiple births and ovarian hyperstimulation syndrome (OHS).
The basic disadvantage to this approach is that the eggs may be released before there is a chance for them to be harvested. Women report far lower stress levels with this approach, however, even though it requires more treatment cycles. In one 2001 study, the live-birth rate was 32%. Not all women are appropriate candidates, however. Women should have regular menstrual cycles and infertility of unknown cause or associated with problems in the fallopian tubes. Pregnancy rates are still very low in older women. Clomiphene. Another gentler alternative to superovulation is the use of clomiphene before IVF, which works slightly better than unstimulated IVF. |
|
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch). |