Ovulation Induction
A normal menstrual cycle usually produces a single mature follicle, which results in the ovulation of one egg. Ovulation induction is a process that uses medication to improve the odds of a pregnancy occurring, by increasing the number of eggs ovulated per cycle.
Fertility specialists often prescribe clomiphene citrate or injectable gonadotropins (synthetic FSH) to their patients to induce the growth and development of more eggs.
Women given these medications are examined on a regular basis (during cycle monitoring hours), via ultrasounds and hormonal blood work, to determine how well their eggs are developing. This gives the doctor the opportunity to adjust the dosage of the patient’s medication as necessary.
Ovulation Induction
Medications
Clomiphene Citrate
Clomiphene citrate is often used as a first option for ovulation induction. Clomiphene is given in pill form to women who do not ovulate regularly, as well as those who ovulate regularly but wish to have more than one egg mature each month. Generally, it is prescribed for five days, and taken during the early part of the menstrual cycle. This medication causes the release of more follicle stimulating hormone (FSH) by stimulating the pituitary gland. Ideally, the increased levels of FSH in the body will result in the maturation of a follicle or follicles and eventually lead to ovulation.
The side effects of clomiphene include:
- Headaches
- Nausea
- Hot flashes
- Blurry vision
- Mood swings
Other risks:
- Some patients taking the drug may develop of a thin endometrial lining that can only be detected with ultrasound, which may make it more difficult to become pregnant.
- Multiple gestation (usually twins) occurs in approximately 8-10% of patients taking clomiphene.
Injectable Gonadotropins
Injectable gonadotropins are another group of fertility drugs often prescribed for ovulation induction. These medications directly stimulate the ovaries to increase the number of developing follicles. The drugs are produced with varying combinations of FSH and/or LH (luteinizing hormone) or as single purified agents.
Patients administer the drug on their own by injection (usually in the lower abdomen or thigh), beginning on the second or third day of their menstrual cycle. The daily injections are continued until their developing eggs are mature and ready to ovulate.
Patients administer the drug on their own by injection (usually in the lower abdomen or thigh), beginning on the second or third day of their menstrual cycle. The daily injections are continued until their developing eggs are mature and ready to ovulate.
FSH and LH
The gonadotropins; FSH, follicle-stimulating hormone, and LH, leutinizing hormone, travel from the brain to the ovaries to promote egg development. These gonadotropins given to patients via injection provide much higher concentrations than the brain would naturally prepare. The gonadotropin preparations available at our clinic include:
- Puregon
- Gonal-F
- Repronex
- Menopur
- Bravelle
Risks of using Gonadotropins
Multiple Pregnancy
One of the major risks of using FSH is multiple pregnancy. Multiple pregnancy occurs in 20-30% of patients taking the drug, and the majority of these are twins. Triplets and quadruplets occur in less than 1% of pregnancies.
Based on the number of developing eggs seen on ultrasound, the doctor will advise a patient of her risk. In cases where too many eggs develop at once and the risk of multiple pregnancy is too high, the patient may be instructed to stop taking FSH and to avoid having intercourse.
Based on the number of developing eggs seen on ultrasound, the doctor will advise a patient of her risk. In cases where too many eggs develop at once and the risk of multiple pregnancy is too high, the patient may be instructed to stop taking FSH and to avoid having intercourse.
Ovarian Hyperstimulation Syndrome (OHSS)
Patients taking FSH also run the risk of developing ovarian hyperstimulation syndrome (OHSS). This condition occurs when too many eggs develop at once and the hormone levels in the blood are too high. In some cases, usually when the HCG injection is given, OHSS can happen after the eggs have ovulated. If the doctor believes a patient is at risk of developing OHSS, she may advise the patient to stop or reduce the amount of FSH she is taking. This will slow the development of the condition and/or prevent it from worsening. For most women who develop this condition, the symptoms resolve on their own over time.
Pain and Inflammation
Pain and/or swelling at the injection site are also common. Many patients relieve their discomfort by applying ice to the area. Relatively few patients also experience bruising or welts around the injection site.
For Your Information:
- The risk of birth defects is not higher in women taking gonadotropins.
- Gonadotropin injections do not increase a woman’s chance of developing ovarian or other types of cancer.
- When gonadtropin injections are combined with an insemination procedure, women with otherwise unexplained infertility may have pregnancy rates of up to 18% per cycle. Please note: This rate may be less when women are older than 38 years of age.
- Women who take gonadotropins because they are unable ovulate on their own (for example, women with polycystic ovary syndrome), may have higher rates of pregnancy – approximately 20-30% per cycle.
