What it means
You are born with all the eggs you will ever have, and the number falls throughout life. Ovarian reserve describes how much of that supply remains. It says something about quantity. It says very little about the quality of the eggs, which depends mostly on age.
The three tests
Doctors usually combine more than one measure, because each has blind spots.
- AMH (anti-Müllerian hormone): a blood test that can be taken on any day of your cycle. AMH is made by the small follicles in your ovaries, so more follicles usually means a higher level.
- Antral follicle count (AFC): a transvaginal ultrasound, usually early in your cycle, that counts the small follicles visible in both ovaries.
- FSH and estradiol: blood tests taken on day two to four of your period. A high FSH level suggests the ovaries need a stronger signal to respond.
What the results can tell you
According to the American Society for Reproductive Medicine, these tests are good at one thing: predicting how the ovaries will respond to stimulation medication. That makes them useful if you are planning egg freezing or IVF, because they help estimate how many eggs a cycle may collect and how to dose the medication.
They can also give an early signal that your reserve is lower than expected for your age, which may change how long you want to wait.
What they can’t tell you
They do not predict whether you can get pregnant on your own. In a study of women aged 30 to 44 with no history of infertility, published in JAMA in 2017, women with low AMH conceived at similar rates to women with normal AMH.
A low result is not a diagnosis of infertility, and a high result is not a guarantee. Results also are not fixed: hormonal birth control can lower AMH readings for a while, conditions such as polycystic ovary syndrome can raise them, and different laboratories use different methods and cut-offs.
Is it worth testing?
It is most useful when the answer would change what you do: if you are considering egg freezing, if you plan to wait several years before trying, or if you have a reason to suspect a lower reserve, such as ovarian surgery, chemotherapy, endometriosis, or a mother or sister who went through menopause early.
Whatever the number, read it with someone who can put it in context with your age and your plans.
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