What is the purpose of the CCT (Clomid Challenge Test)?
We must establish a measure of egg quality. I discussed this issue in the section on Reproductive Aging. ALL women will eventually loose their fertility (menopause). Sometimes, infertility represents the premature onset of menopause. The CCT is a test to determine the presence of diminished egg quality.
The CCT should be thought of as a stress test of the reproductive hormone system. Endocrinologists use stress tests to diagnose diabetes, thyroid disease and other endocrine system disorders.
How is the CCT performed?
We ask our patients to call us on the first day of normal full menstrual flow. We define this as Menstrual Cycle Day 1. (For practical reasons, if the menses starts after 5 PM then we use the following day as Day 1 to prevent concern about not being able to call the office when it is closed.)
We schedule an appointment on Cycle Day 2-4 depending on the clinic and the patient’s schedule. During the appointment, we draw a blood sample for hormones (FSH, LH, Estradiol, AMH – Anti-Mullerian Hormone) and then we perform a vaginal ultrasound of the pelvic organs but we are most interested in the ovaries. We measure the size of the ovaries (volume) and count the number of antral follicles (AFC – Antral Follicle Count).
The woman then takes a fertility drug, Clomid (Clomiphene Citrate) 100 mg, for 5 days and then returns for a blood level of FSH on Cycle Day 10.
If the blood level of FSH is elevated then the egg quality is reduced. The higher the level of FSH the lower the egg quality. For any value of FSH, the older the woman the lower the fertility potential.
Many doctors only measure FSH on Cycle Day 2-3, Why do you do the CCT?
We have found in our practice that about 40% of our abnormal values come from the Day 10 FSH after Clomid. Thus, we would have suggested that the egg quality was good when in fact it was compromised in 40% of our infertile patients. Forty percent seems like a high number to me. The information we gain from the CCT allows us to better inform and counsel our patients so that they can make better decisions regarding the diagnosis and treatment of their infertility problem.
Watch this brief video for the CCT only portion. I have a longer version which includes more information about reproductive aging on that page (click here)
Ovarian Reserve Testing 2: FSH & CCT from Cascade Fertility on Vimeo.