Ovulation Induction

Ovulation induction is a term that refers to the administration of medication to stimulate ovulation. These medications range from letrozole to gonadotropins and combinations of the two. Gonadotropins are injectable ovulation stimulating hormones that are identical to the hormones secreted by the body.

With the administration of these injectable medications, we are able to increase the circulating levels of these hormones, resulting in the stimulation and growth of multiple eggs. In addition to increasing the number of eggs with the use of gonadotropins, we control timing factors, such as when ovulation occurs, to maximize the chance of becoming pregnant.

Overview of Ovulation Induction and Intrauterine Insemination Process


A variety of medications are utilized for ovulation induction. The simplest is letrozole, which can be taken orally. Letrozole is typically used alone or in conjunction with injectable gonadotropins to help stimulate the ovaries.

There are multiple types of gonadotropins available for ovulation induction. These products include Follistim, Gonal- F, Bravelle, and Repronex. The most commonly used gonadotropin for ovulation induction at Coastal Fertility Specialists is human menopausal gonadotropin (hMG) which contains both Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH).

Cycle Monitoring

We closely monitor all cycles involving gonadotropins. We can monitor a patient’s response in two ways:

  1. Estradiol Levels – Estradiol is released into the blood by the growing follicles as they respond to medications. Tracking this rise in estradiol levels can help us follow egg development.
  2. Vaginal Ultrasounds – Vaginal ultrasounds can visualize the number of developing eggs and measure their size and growth. The picture on the upper left shows multiple eggs developing on the ovary and the picture on the bottom right shows good endometrial development (the inside of the uterus).

Early in the stimulation cycle we measure estradiol levels and perform vaginal ultrasounds every couple of days to assess growth. Towards the end of the cycle we perform these assessments more frequently to control the timing factors that will maximize the chances of becoming pregnant and minimize side effects.

Ovulation induction cycles are usually followed by the administration of human chorionic gonadotropin (hCG), an injection to induce ovulation. Intrauterine inseminations are performed 30 to 40 hours after the hCG injection which is just prior to ovulation. Intrauterine inseminations use specially prepared and concentrated sperm, which helps to maximize the number of sperm available for fertilization.

Side Effects and Risks

There are side effects and risks associated with gonadotropin use. The most common side effects of these medications include discomfort or “fullness” in the lower abdomen, bloating, headache or fatigue. Patients can also experience discomfort in the area of injection. Massaging the area or applying heat is often helpful.

Perhaps the most significant risks of using injectable gonadotropins are multiple gestation and ovarian hyperstimulation. Ovulation induction can have up to a 20% incidence of multiple gestation (more than one fetus).

The majority of these pregnancies are twins, however, more than two fetuses can sometimes develop. Vaginal ultrasounds help us to determine how many follicles you have developing, but this is only a guide and not a specific count. If you should develop too many follicles, you may be counseled to stop treatment to avoid the risk of multiple pregnancies. Pregnancy with three or more fetuses at a time places both the mother and fetus at high risk for miscarriage, pre-term delivery and bleeding.

At Coastal Fertility Specialists we take this risk very seriously and will monitor your progress very closely to help minimize the chances of a multiple pregnancy.

Ovarian hyperstimulation is also a possible side effect of ovulation induction and typically occurs 5-7 days after hCG injection. After hCG is given and ovulation occurs, the ovaries will frequently enlarge. If pregnancy results, the ovarian enlargement may persist for up to six weeks.

In general, the symptoms associated with ovarian hyperstimulation are mild and may include lower abdominal pain, heaviness and bloating. Sometimes shortness of breath may also develop. It is extremely uncommon for hyperstimulation to result in any severe medical problems or hospitalizations. We will closely follow your progress to avoid problems of ovarian hyperstimulation.