Medications for Ovulation Induction

Fertility Medications Used at Our Practice

At Northern California Fertility Medical Center, many of our treatments involve the use of fertility medication to help our patients achieve conception, whether naturally or through in vitro fertilization. We feel it is important for our patients to understand how and why these prescriptions are used, what their risks are, and how they work in the body. The following is a brief description of the most common types of fertility medication used at our practice.

Clomiphene Citrate

Due to its effectiveness and relatively low level of risk, clomiphene citrate is the most commonly prescribed fertility medication and is generally the first line of treatment for women with certain types of infertility. It can be used to stimulate ovulation to improve the chances of conception, or in preparation for a course of in vitro fertilization. It is also often used in fertility testing to determine ovarian reserve in women who are in their later reproductive years.

Aside from testing and IVF applications, women who are treated with clomiphene citrate are generally those who are anovulatory (do not ovulate), oligo-ovulatory (ovulate irregularly) or dysovulatory (ovulate irregularly due to a hormonal imbalance). This fertility medication can help to stimulate and regulate ovulation in most women. However, it is only effective if there is an adequate supply of eggs in the ovaries. Women with low ovarian reserve (generally over the age of 40) will most likely be advised to consider alternative options, such as egg donation.

Clomiphene citrate is administered orally for five days in the early stages of the menstrual cycle. Many fertility practices give this fertility medication from the fifth through the ninth day of the patient’s cycle. However, at Northern California Fertility Medical Center, we believe that earlier administration (from day three through day seven) optimizes the development of the ovarian follicles. These follicles contain the maturing eggs and release the estrogen that is necessary to prepare the lining of the uterus for implantation.

With clomiphene citrate therapy, 80 percent of pregnancies occur within the first three cycles of treatment. After three cycles, success rates decrease significantly and patients will most likely be advised to consider alternative treatments, such as gonadotropin therapy.

Clomiphene citrate mimics the chemical structure of estrogen. By blocking the estrogen receptors in the body and tricking the endocrine (hormone) system into sensing a decrease in the body’s estrogen levels, this fertility medication triggers the release of extra follicle stimulating hormone (FSH). In turn, FSH causes the ovaries to develop follicles and begin ripening eggs in preparation for ovulation. As the follicles develop, they release additional estrogen, which causes the lining of the uterus to thicken in preparation for implantation. Once estrogen levels reach a certain point, luteinizing hormone (LH) is released, which triggers the final maturation and release of the eggs (ovulation).
The risks of clomiphene citrate are extremely low in comparison to other hormone therapy options. Some women may experience mild side effects such as excess flatulence (gas), hot flashes, or minor visual disturbances. These effects will disappear after the fertility medication is no longer being taken. The occurrence of ovarian hyperstimulation syndrome (OHSS), a potentially serious condition, is extremely rare with the use of clomiphene citrate.


Gonadotropins are the naturally occurring hormones that stimulate the gonads (ovaries in the female, testes in the male). Follicle stimulating hormone (FSH) and luteinizing hormone (LH) are the primary gonadotropins. A fertility medication such as Repronex®, Bravelle®, Pergona, Follistim®, or Gonal-f® can be used to act on the ovaries in the same way as naturally-occurring gonadotropins, stimulating follicular development and ovulation.

In most cases, gonadotropin therapy is used when treatment with clomiphene citrate has failed because these more aggressive fertility medications carry somewhat higher risks.

Gonadotropins are administered by injection. The dose will vary from woman to woman, and is determined by the doctor based on the patient’s body weight, age, hormonal evaluation results, and the doctor’s previous experience.

During treatment with gonadotropin-based fertility medication, the patient will be carefully monitored through ultrasounds and blood tests to determine the precise timing of ovulation and to ensure that no complications are arising.

Once the follicles have reached maturity, a dose of human chorionic gonadotropin (hCG) is administered. This triggers the final maturation of the eggs, followed by their release into the fallopian tubes.

While clomiphene citrate works by triggering the body to release FSH, gonadotropins simply mimic the effects of FSH in the body and directly stimulate the ovaries to develop follicles and begin the ripening of the eggs. The dose of hCG that is given at the end of the treatment cycle takes the place of the naturally occurring luteinizing hormone (LH) that causes the eggs to complete their maturation process and be released from the follicles. Because this type of fertility medication bypasses the body’s natural monitoring system, its effects, as well as its risks, are stronger than those of clomiphene citrate treatment.

The most common risk of gonadotropin therapy is multiple pregnancy. Most cases of multiple pregnancy involve twins, but three or more embryos can put the mother at risk for complications. If the doctor determines that the number of follicles being stimulated is too high and the risk of multiple pregnancy too great, the patient may choose to cancel the cycle and avoid pregnancy, undergo aspiration of some of the follicles to reduce the number of eggs that will be released, or undergo in vitro fertilization. During an IVF procedure, all of the eggs will be aspirated, then fertilized outside of the body before a controlled number are placed into the uterus.

Another risk associated with fertility medication is ovarian hyperstimulation syndrome. This condition can range from mild to severe and symptoms include nausea, diarrhea, shortness of breath, fluid retention, and weight gain. Most often seen in women who have very high estrogen levels and a large number of follicles, this condition is rare, especially in its more serious forms. However, our doctors will monitor patients undergoing gonadotropin therapy for signs of OHSS to ensure that, should it develop, it can be identified and treated quickly.