Ovarian Reserve Testing

It would be nice to have a reliable test to determine how many eggs a woman has remaining and how good they are at any point in time.

There are some screening tests for "ovarian reserve" as the fertility doctors call it. Is there a good reserve of eggs remaining in the ovaries?

This page is about day 3 FSH and estradiol testing. The ovarian reserve page has more on egg quantity and quality issues and other ovarian reserve screening tests.

Antral follicle counts and response of the ovaries to stimulation with injectable gonadotropins are other variables that affect the overall chance for conception when we attempt IVF - in vitro fertilization.

Female age is a very important variable. However, a woman can be 42 and still have some good quality eggs (and still be fertile), or she can be 25 with poor quality eggs and be infertile, although this is rare.

In general, egg quantity and quality tends to decline slowly starting in the early 30's, and then much faster in the late 30s and early 40s.

What does FSH hormone do?

Follicle stimulating hormone (FSH) is one of the most important hormones involved in the natural menstrual cycle as well as in pharmacological (drug-induced) stimulation of the ovaries. It is the main hormone involved in producing mature eggs in the ovaries.

FSH is the same hormone that is contained in the injectable gonadotropins which are used to produce multiple eggs for infertility treatment.

What produces FSH hormone?

Both FSH and LH hormone are produced by the pituitary gland at the base of the brain. When a women goes into menopause she is running out of eggs in her ovaries. The brain senses that there is a low estrogen environment - and signals the pituitary to make more FSH hormone. More FSH is released from the pituitary in an attempt to stimulate the ovaries to produce a good follicle and estrogen hormone.

Women in menopause usually have high FSH hormone levels that are above 40 mIU/ml. As women approach menopause their baseline FSH levels (day 3 of their cycle) will tend to gradually increase over the years. When they run out of follicles capable of responding, their FSH will be quite high and they stop having menstrual periods.

Why do we measure the FSH level on day 3?

By measuring a woman's baseline FSH on day 3 of the cycle (we do it on day 2, 3, or 4), we get an indication as to whether she has normal "ovarian reserve".

Therefore, if the baseline FSH is elevated the ovarian reserve (how many eggs are left) is reduced (sometimes the egg quality is also reduced).

Day 3 estradiol testing

A blood estradiol level on day 3 (we do it on any day between days 2 and 4) of the menstrual cycle is a way to potentially discover some of those women with a normal day 3 FSH that may in fact have decreased egg quantity and quality.

What we want on day three is a low FSH level in conjunction with a low estradiol level. If the FSH is normal but the estradiol level is elevated, the elevated estradiol will often be artificially "suppressing" the FSH level down to the normal range.

The idea of using day 3 estradiol levels as an adjunct in evaluating egg quantity and quality is relatively recent. Clearly defined cutoff values for normal are not well established. We like to see the day 3 estradiol less than about 80. In our clinic, levels of 80-100 are borderline, and over 100 are abnormal. We repeat borderline or abnormal results in another menstrual cycle to try to get a "true" FSH.

There is some evidence that an elevated day 3 estradiol indicates a problem with ovarian reserve. This is sometimes the case, but more often the issue is just that the elevated estrogen level is "masking" the potential for detecting low reserve by suppressing FSH into the normal range.

Clomiphene challenge test

A clomiphene challenge test is a dynamic type of test that can discover some cases of poor ovarian reserve that are still showing a normal day 3 FSH.