Fertility Testing for Women
Ovarian Reserve
Among fertility specialists, ovarian reserve is the equivalent of a “biological clock.” Most people are aware that women have a biological clock for fertility; a limited time to complete childbearing, after which having a baby becomes unlikely. What most patients are not aware of is that the biologic clock is not the same for every woman. With age, a woman’s fertility decreases and her miscarriage rate and chance of having a baby with a genetic abnormality increases.
Why do some women lose their fertility sooner than others?
- Women are born with all the eggs they will every have – approximately 2 million eggs.
- Everyday, including through childhood, women lose eggs. No matter if she is on birth control, if she is pregnant, or even if she has infrequent menstrual cycles, she is always losing eggs.
- Additionally, as a woman ages, the cells around the eggs and the eggs themselves can accumulate damage which is never repaired.
- Therefore, as a woman ages, not only does she have fewer eggs, but a higher percentage of her eggs are abnormal due to damage from the aging process. If she ovulates an abnormal egg, her chances of pregnancy are lower, and her chances of miscarriage and having a baby with an abnormality are higher.
- Women with diminished ovarian reserve were either born with fewer eggs than average, lost them more quickly than average, or over time the eggs accumulated more damage than average.
The picture above illustrates the phenomena of egg depletion over time. The white circles represent normal eggs and the grey circles represent abnormal eggs. Notice that at birth, when egg number is at a maximum, there are a minimum number of abnormal eggs. At the onset of puberty, a woman has already lost approximately 75% of the eggs she was born with. By the late 30s, egg number has continued to decline and notice that now the ratio of normal to abnormal eggs has shifted, with a much higher proportion of abnormal eggs. By the time of menopause, almost all remaining eggs are abnormal.
While many cases of diminished ovarian reserve are never explained, common causes are:
- Age >35
- Smoking
- Genetic Abnormalities (Fragile X Premutation, or X chromosome abnormality)
- Cancer treatments with radiation and certain chemotherapy agents
- The surgical removal of part or all of an ovary
With ovarian reserve testing your physician can estimate whether your eggs have the fertility potential of most women your age, or if your ovaries demonstrate accelerated aging. In practical terms, ovarian reserve is a measure of the number and quality of eggs a woman has in her ovaries.
In cases where a woman has poor quality eggs, or few eggs, she may have a much more difficult time conceiving and she is said to have “diminished ovarian reserve.”
There is no cure for diminished ovarian reserve and generally, a woman’s diminished fertility potential is predicted by any abnormal ovarian reserve test (meaning that while repeating the test may yield a normal result, any prior abnormal result predicts significant difficulty conceiving either spontaneously or with aggressive treatments including IVF). However, it is very important to understand that even a significantly abnormal test result CAN NOT exclude the possibility of pregnancy. Ovarian reserve testing best predicts outcomes with IVF.
For more information on ovarian reserve testing for fertility, please see:
Cycle Day 3 FSH and Estradiol
Antral Follicle Count
AMH (anti-Mullerian hormone)
CCT
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