Ovarian reserve refers to the number and quality of eggs remaining in your ovaries at any given point in time. It’s a term most often used in fertility medicine to estimate how your ovaries might respond to treatment, though it also comes up in broader conversations about reproductive aging. Every person with ovaries is born with a fixed supply of eggs that declines steadily over a lifetime, and ovarian reserve is essentially a snapshot of where you are in that process.
How Your Egg Supply Changes Over Time
Unlike sperm, which are produced continuously, eggs are never replenished. You’re born with your entire lifetime supply, and the count only goes down from there. At birth, most people have roughly 1 to 2 million eggs. By puberty, that number has already dropped to about 300,000 to 400,000. By age 40, the average is around 25,000.
Most of those eggs don’t get released during ovulation. The vast majority are lost through a natural process called atresia, where immature follicles break down and get reabsorbed by the body. Only about 400 to 500 eggs will ever be ovulated across a full reproductive lifespan. The rest simply disappear on their own timeline.
Age is the single biggest factor driving this decline, but it isn’t the only one. Smoking accelerates egg loss. Certain medical treatments, particularly chemotherapy, can damage the follicle pool directly. Genetics play a role too. Some people inherit a smaller starting supply or a faster rate of depletion. Ovarian surgery and endometriosis are also linked to reduced reserve. Even conditions during fetal development, like a mother’s nutrition or smoking during pregnancy, can affect how many eggs a baby is born with.
Quantity vs. Quality
Ovarian reserve technically encompasses both the number of eggs and their quality, but these two dimensions don’t always move in lockstep. Egg quality refers to whether an egg has the correct number of chromosomes and enough cellular energy to develop into a viable embryo after fertilization. Quality declines with age because eggs are more prone to chromosomal errors the longer they’ve been stored in the ovaries.
This distinction matters. A younger person with a low egg count may still have eggs of good quality, giving them a reasonable chance of conception. An older person might have a decent number of eggs remaining, but a higher proportion of those eggs will carry chromosomal abnormalities. Current testing methods are much better at measuring quantity than quality, which is one of the key limitations of ovarian reserve testing.
How Ovarian Reserve Is Measured
Three main tests are used in clinical practice, often in combination.
AMH (anti-Müllerian hormone) is a blood test that can be drawn at any point in your menstrual cycle, making it the most convenient option. AMH is produced by the small follicles developing in your ovaries, so higher levels generally indicate more eggs in reserve. Median AMH values drop with age: around 3.5 ng/mL in the late twenties, 2.4 ng/mL in the early thirties, 1.3 ng/mL in the late thirties, and 0.5 ng/mL in the early forties. Values below roughly 0.5 to 1.0 ng/mL are often used as a threshold for identifying diminished reserve, though labs vary in their cutoff points.
Antral follicle count (AFC) is done via transvaginal ultrasound during the first few days of your cycle. A technician counts the small, fluid-filled follicles visible on both ovaries. A count of 8 to 10 follicles is generally considered a normal response indicator. Fewer than that suggests a reduced reserve, while counts above 14 are associated with a robust or even excessive response to fertility medications. AFC and AMH are considered the two most reliable markers and tend to correlate well with each other.
Day 3 FSH (follicle-stimulating hormone) is measured through a blood draw on the second, third, or fourth day of your menstrual cycle, usually alongside estradiol. FSH is the hormone your brain sends to your ovaries to recruit follicles each month. When fewer follicles are available, your body compensates by producing more FSH, so higher levels can signal diminished reserve. Levels below 10 to 12 mIU/mL are generally considered favorable. The limitation is that FSH only reliably flags a problem at very high levels, so it can miss many people with reduced reserve.
What These Tests Can and Cannot Tell You
This is where many people get confused, and understandably so. Ovarian reserve tests are good at predicting how your ovaries will respond to fertility medications during IVF. A low AMH or low AFC suggests you may produce fewer eggs during a stimulation cycle, which helps your fertility team adjust medication doses and set realistic expectations. A high result may flag the risk of overstimulation, which also guides treatment decisions.
What these tests cannot do is predict whether you’ll get pregnant on your own. A large study of 750 women aged 30 to 44 with no known fertility issues found no association between AMH levels and the likelihood of conceiving naturally within 6 or 12 months. Similarly, an elevated day 3 FSH (10 mIU/mL or higher) did not predict a lower chance of pregnancy in women who had been trying for fewer than three months. AFC is a reliable predictor of stimulation response but a poor predictor of pregnancy outcomes.
The American Society for Reproductive Medicine specifically recommends against using ovarian reserve tests as a screening tool for women who haven’t been diagnosed with infertility. These tests are not designed to tell a healthy person whether they should rush to conceive or freeze their eggs. They are diagnostic tools meant to guide treatment for people already experiencing difficulty.
Diminished Ovarian Reserve as a Diagnosis
Diminished ovarian reserve (DOR) is a clinical diagnosis given to people of reproductive age who still have regular periods but whose ovaries respond poorly to stimulation compared to others their age. It’s not the same as menopause or even perimenopause. Your cycles may look completely normal from the outside.
DOR is diagnosed through the tests described above, typically when results fall below expected thresholds for your age group. It’s an important cause of infertility, but it doesn’t mean pregnancy is impossible. People with DOR may need more aggressive or tailored approaches to fertility treatment, and their expected egg yield during IVF tends to be lower. Younger people with DOR often have better outcomes than older people with the same test numbers, likely because their remaining eggs tend to be higher quality.
What Affects Your Reserve Beyond Age
While age drives the bulk of ovarian reserve decline, several factors can push it lower than expected for your age. Smoking is one of the most well-established accelerators, with research consistently linking it to earlier depletion of the follicle pool. Ovarian surgery, even for benign cysts, can reduce the number of functioning follicles. Endometriosis is associated with diminished reserve, both from the disease itself and from surgical treatment. Chemotherapy and pelvic radiation are known to cause significant, sometimes permanent, damage to the ovarian follicle pool.
Genetics also play a meaningful role. Some people are simply born with fewer eggs or lose them at a faster rate due to inherited factors. Certain genetic conditions, including Fragile X premutations and Turner syndrome mosaicism, are linked to premature ovarian insufficiency. If your mother or sisters experienced early menopause, your own reserve may follow a similar trajectory.
There is no proven way to increase your ovarian reserve once it has declined. Supplements and lifestyle changes marketed as “boosting” egg count do not create new eggs. What you can potentially influence is egg quality through factors like not smoking, maintaining a healthy weight, and managing oxidative stress, though the evidence for specific interventions remains limited. The egg supply you have is the supply you have, and the primary variable is how quickly it decreases.