How does actual ovarian age compare and correlate with actual chronological age? There is a strong correlation, but it is not by any means absolute.
A woman is said to have “low ovarian reserve” if her ovaries function in a way consistent with older women. If you have been told you have diminished or low ovarian reserve, there are some different possibilities.
AGE: If you are over 35, having dimished ovarian reserve is actually quite normal. In general, female fertility declines almost insignificantly up to age 30. Then from 30-35, it declines significantly but not rapidly. It’s not until age 35-40 that fertility takes a rapid decline. So most women over 35 would be expected to have diminished ovarian reserve.
BLOOD TESTS: Blood tests can also give a clue as to how somebody’s ovaries are expected to function. The two most famous of these tests are FSH and AMH. If you are under 35, but your AMH or FSH are bad, then there is a high possibility that your ovaries perform like those of someone who is older than you really are.
OVARIAN VOLUME and APPEARANCE: The size of a woman’s ovaries has a general correlation with age. A young teenager is expected to have fairly large ovaries, that are thought to be full of a reserve supply of eggs. The ovaries of a 45 year-old are usually much smaller and have been depleted of many of the eggs that were once there. Besides just the size, it is helpful to look at the “texture” of the ovaries on ultrasound. Are there many antral follicles (units that have the potential to grow to become eggs) or are there large areas of inactive “dead” ovarian tissue?
PERFORMANCE: Performance refers to ability to grow eggs of good quality. I find this to be the most important factor. There have been patients encountered in the past who were older, had poor blood tests and poor ovarian volume / appearance, but when they were given fertility enhancing drugs, they grew a number and quality of eggs that were surprisingly good, eventually resulting in a healthy baby.
The take-away message is that estimates of ovarian aging are just that — estimates. You can find many stories of women who were thought too old to have a baby, thought to have too high a FSH or too low an AMH to have a baby, or who had ovaries too small or too devoid of antral follicles to have a baby, but who in the end wound up having a healthy baby. Having said that, it is certainly better for your odds of you are younger, have better lab values and better ovarian ultrasound findings.