Ovarian Function and Reserve

A woman is born with her lifetime supply of eggs. Unlike men, who are constantly producing new sperm, a woman does not create any more eggs after birth. Throughout her childbearing years, a woman will ovulate the healthiest eggs first. Furthermore, as the quantity and quality of eggs decline through the childbearing years, the remaining eggs may not be as healthy, which helps explain why the ability to conceive declines with age. For women under 30, the chance of becoming pregnant is approximately 20-25% per cycle for the first year of attempting to conceive. After 40 years of age, the chance of natural conception drops to less than 5% per month. Additionally, increasing age also leads to lower pregnancy rates from infertility therapies. Once all the eggs are depleted, menopause occurs, which commonly happens around age 51 in American women.

A variety of non-invasive diagnostic studies can be obtained on women to help determine their ovarian reserve (the remaining eggs). Although the determination of the absolute number of eggs is not obtainable, diagnostic studies are available to help estimate a woman’s ovarian reserve. This information is important when counseling couples and directing them towards appropriate treatments.

At Dallas IVF, at least one, if not more, of the below described studies will be requested by one of our physicians:

• Day 3 FSH. Follicle stimulating hormone (FSH) is produced by the brain in the region known as the pituitary. As ovarian function declines, FSH values increase in order to try and stimulate the ovary to mature eggs. Most healthy and young reproductive aged women will have FSH values well below 10. An FSH on cycle day 2 or 3 that is above the value of 10 reflects a decline in ovarian reserve. Many studies have shown that women with high FSH values have lower conception rates when undergoing infertility treatments.

• Clomid Challenge Test (Clomiphene Citrate Challenge Test). This is an extension of the day 3 FSH test. A blood test measuring FSH levels is obtained on the 2nd or 3rd day of the menstrual cycle. Clomiphene citrate at a dose of 100 mg per day is taken orally on cycle days 5 through 9. FSH is checked again on day 10. An FSH level greater than 10 on either day 3 or day 10 is often considered abnormal.

• Resting (Antral) Follicle Count. A transvaginal ultrasound evaluation of the ovaries is conducted at the beginning of a woman’s menstrual cycle and the number of resting/unstimulated ovarian follicles is noted. If a woman has a low number of resting follicles, response to fertility medications may not be optimal.
• Ovarian volume. This study measures the ovarian volume in three dimensions, examined through the use of a transvaginal ultrasound. As ovarian function declines, so may ovarian volume.