Friday 26 October 2007

Clomiphene Challenge Test

Women are born with their lifetime supply of eggs within the ovaries. Each month follicles, each of which contains one egg, are recruited under the influence of follicle stimulating hormone. One follicle will become dominant, develop to maturity, and be ovulated. Ovarian reserve is a measure of the “quality” of the eggs remaining within the ovaries. Ovarian
reserve naturally declines as a woman ages and approaches the menopause. However, diminished reserve can occur in younger women due to perimenopause, genetics, or for unknown reasons.
In the standard infertility evaluation, levels of the hormones FSH, LH, and estradiol are measured on day 3. An elevated FSH level on day 3 is one indication of poor ovarian reserve or that the menopause is approaching. The clomiphene citrate challenge test (CCCT) provides an additional assessment of ovarian reserve. The clomiphene citrate challenge test (CCCT) is a sensitive means to measure ovarian reserve and is often conducted if the FSH level is 10-15 mIU/mL or the E2 is >65 pg/mL. It is performed by measuring the day 3 FSH and estradiol levels, the patient takes 100 mg tablets of Clomiphene Citrate on cycle days 5-9, and her FSH is measured again on day 10. A poor CCCT test, regardless of patient age, indicates that there will be a decreased response to injectable medications in assisted reproductive technology cycles. Pregnancy success rates are lower in these women and there is an increased chance of miscarriage. The clomiphene citrate Challenge Test is routinely performed at our clinic in women aged 38 years or older regardless of how the cycle day 3 levels look. This will identify patients with incipient ovarian dysfunction. The clomiphene citrate challenge test should also be considered in women of any age with otherwise unexplained infertility as approximately 30% will show abnormalities that adversely impact their prognosis with fertility treatment.
A level from 10-12.5 mIU/mL predicts resistance to fertility medications and a diminished prognosis. At 12.5-15 mIU/mL, the prognosis is poor but pregnancies do occur with aggressive treatment. Levels greater than 15 mIU/mL indicate that infertility treatment with the patient’s own eggs is not likely to succeed and that egg donation should be offered. Patients with any FSH level greater than 10 mIU/mL should be referred to a fertility specialist for further evaluation. A poor clomiphene citrate challenge test indicates that it is unlikely that the couple will be successful using in vitro fertilization, IVF. Some clinics do not offer IVF to couples failing the CCCT test and others offer it but clearly explain the poor chance of success. Donor egg IVF is the best option for these couples.

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