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The Clomid Challenge Test
The Clomid Challenge Test (also know as the clomiphene citrate challenge test, or CCCT) is an infertility blood test to measure a woman’s ovarian reserve — the health of her ovaries and the quality and quantity of the eggs (oocytes) they contain.
When a woman is born, she has a lifetime supply of eggs within her ovaries. Each month, the follicle stimulating hormone (FSH) recruits and stimulates a follicle, which becomes dominant and matures into an egg. Ovulation occurs when the mature egg is released from the ovary, pushed down the fallopian tubes and is available to be fertilized. But even if a woman is ovulating regularly, she may still have poor quality eggs.
Ovarian reserve can decline for many reasons, with age being the most common. Genetics, smoking, radiation, chemotherapy and unknown reasons can also have an effect.
Understanding Follicle Stimulating Hormone (FSH)
There are no perfect ways to estimate ovarian reserve; however FSH levels under certain conditions provide the best available estimate.
Abnormal FSH levels can predict low fertility, and researchers have found that women undergoing in vitro fertilization who had the highest levels of FSH had the lowest average pregnancy rates and the highest miscarriage rates.
Understanding the Clomid Challenge Test
The Clomid Challenge Test looks primarily at FSH at two different time points during a woman’s menstrual cycle. The patient’s FSH is usually determined on Day 3; she is given Clomid on Days 5 through 9; and her FSH is retested on Day 10.
“The Clomid Challenge Test is a measure of ovarian reserve that’s typically done to see how the brain responds to fooling it about estrogen levels,” says Eric Flisser, M.D., a fertility doctor with Reproductive Medicine Associates of New York. “When Clomid is administered and the brain can’t sense estrogen, it produces a limited additional FSH.”
“When the response to Clomid is by a rapid rise, or a high rise, in the FSH level,” Dr. Flisser continues, “that could indicate the brain is having a more difficult time getting a response from the ovary and that ovarian reserve is diministhed.”
Clomid tends to elevate FSH levels; however, women with a normal response are able to return the FSH levels to baseline by day 10, while the day 10 FSH is often elevated in women with diminished ovarian reserve.
What Does a Poor Clomid Challenge Test Mean?
Regardless of a woman’s age, having a poor Clomid Challenge Test may indicate several things for a patient:
- lower response to injectable fertility drugs in assisted reproductive technology cycles
- fewer eggs retrieved
- lower pregnancy rate with IVF and intrauterine insemination (IUI)
- higher miscarriage rates
- increased risk for chromosomally abnormal embryos.
Some fertility clinics may not offer IVF to women who have a poor Clomid Challenge Test result.