A woman’s age is one of the most important factors affecting whether she is able to conceive and give birth to a healthy child. This is due to several changes that are a natural part of aging. The number and quality of eggs (ovarian reserve) decreases naturally and progressively from the time a woman is born until the time she reaches menopause. This decline is gradual until her early 30s but accelerates quickly after her mid-30s. In terms of ovarian reserve, a typical woman has 12% of her reserve at age 30 and has only 3% at age 40. 81% of variation in ovarian reserve is due to age alone, making age the most important factor in female infertility.
The main goal of ovarian reserve testing is to identify those individuals who are at risk of decreased or diminished ovarian reserve, commonly known as DOR. Although ovarian reserve testing cannot predict the end of one’s reproductive years, results outside the range expected for a patient’s age can encourage the individual to pursue more aggressive treatment options to achieve pregnancy. Compared with women of similar age, women with diminished ovarian reserve commonly have regular menses but a reduced quantity of eggs and thus may have a limited response to ovarian stimulation with fertility medications and a reduced fecundity (probability of achieving a live birth in a single reproductive cycle).
The number and quality of your eggs (ovarian reserve) can be estimated using blood tests for follicle-stimulating hormone (FSH) or antimüllerian hormone (AMH) levels. An ultrasound is sometimes used to count the number of follicles (antral follicle count [AFC]). There is no single test that measures ovarian reserve perfectly. Age is the most important indicator of egg quality.
1. Day 3 FSH and Estradiol Test
On day 3 of a woman’s menstrual cycle, a baseline blood test is done to measure her Follicle Stimulating Hormone and how much her body is producing. If her FSH baseline is elevated, this might be an indication of poor egg quality and quantity. Estradiol levels are also evaluated. If a FSH baseline comes back normal, but there is an increase in Estradiol production, there is reason to suspect that the Estradiol is suppressing the FSH levels.
2. Anti-Mullerian Hormone (AMH) Levels Test
AMH is a hormone produced by ovarian follicles, and is responsible for the production of oocytes. AMH is the most accurate predictor of a woman’s egg supply. This test can be more accurate than FSH because there is no fluctuation from month to month and the test is not dependent on a woman’s menstrual cycle, which means women can have the test at any point. AMH is secreted by the small antral follicles found in the ovaries at the start of the cycle. A higher AMH level would indicate a large amount of antral follicles and a strong ovarian reserve where as a lower value would lead your physician to believe there has been a decrease in the ovarian reserve. Using birth control pills can falsely lower AMH levels. In order to get the most accurate AMH measurement its best to be off birth control pills for at least 1-2 months
3. Transvaginal Ultrasound
The number of antral follicles (or resting follicles) visible during a transvaginal ultrasound can give doctors an idea of how many eggs remain in the ovary. A woman has both antral and primordial follicles, the latter being microscopic. Each follicle contains an egg awaiting maturation. If a woman has a fair number of antral follicles visible on an ultrasound, this is indicative of a normal ovarian reserve. If there are only a few visible, she most likely has a small amount of primordial follicles available. Similar to AMH levels birth control pills can decrease the antral follicle counts.
When test results suggest a diminished ovarian reserve, if appropriate, an infertility evaluation should be initiated. It is also reasonable to counsel women with DOR that the window of opportunity to conceive may be shorter than anticipated and attempting to conceive sooner rather later should be encouraged.