Three tests give you the clearest picture of your remaining egg supply: a blood test for anti-Müllerian hormone (AMH), an ultrasound count of small follicles on your ovaries (called the antral follicle count, or AFC), and a blood draw for follicle-stimulating hormone (FSH) taken on day three of your period. Each measures something slightly different, and none of them tells you everything you want to know. Understanding what these numbers actually reveal, and what they quietly leave out, matters more than the numbers themselves.
Why You Have a Finite Egg Supply
Your ovaries come pre-stocked. The pool of primordial follicles, each containing an immature egg, is fixed before birth and shrinks steadily from that point forward until menopause.1PubMed. A model conforming the decline in follicle numbers to the age of menopause in women Of that original supply, roughly 99.9% of follicles never release a mature egg. Instead, they undergo a natural process called atresia, where the body eliminates follicles that don’t get selected for ovulation.2PubMed Central. Mechanisms of follicular atresia: focus on apoptosis, autophagy, and ferroptosis Only a tiny fraction survive to ovulation across your reproductive years. When fertility specialists talk about “ovarian reserve,” they mean the size and quality of whatever is left in that dwindling pool at the time you’re tested.
The Three Main Tests
Anti-Müllerian Hormone (AMH)
AMH is a hormone produced by the small growing follicles in your ovaries. The more of these follicles you have, the more AMH circulates in your blood, so the level acts as a rough proxy for the size of your remaining egg pool. A simple blood draw is all it takes. Unlike some other fertility hormones, AMH can be tested on any day of your cycle, which makes it convenient. It has become the most widely used single marker of ovarian reserve, and it’s the test that at-home fertility kits typically offer.
AMH correlates more tightly with the number of early antral follicles than either age or FSH levels do.3PubMed Central. The correlation of the antral follicle count and Serum anti-mullerian hormone That said, “more tightly” does not mean perfectly. It’s a statistical association, and individual results can surprise you.
Antral Follicle Count (AFC)
An AFC is performed via transvaginal ultrasound, usually in the first few days of your menstrual cycle. The technician or doctor counts the small follicles visible on each ovary. These antral follicles are the ones that have begun growing during that cycle and could potentially respond to stimulation. A combined count from both ovaries below about five to seven follicles is considered low and may indicate diminished ovarian reserve.4PubMed Central. Diminished ovarian reserve, premature ovarian failure, poor ovarian responder–a plea for universal definitions AFC has the advantage of being a direct visual count rather than an indirect hormone measurement, but it depends on the skill of the person performing the scan and the quality of the equipment.
Day-3 FSH and Estradiol
Follicle-stimulating hormone is the signal your brain sends to your ovaries to grow follicles each month. When fewer follicles remain, the brain has to shout louder to get a response, so FSH levels rise. A blood draw on day three of your cycle captures this baseline. Estradiol (a form of estrogen) is typically measured alongside it, because a high early estradiol level can artificially suppress FSH and mask the true picture. In one study, no pregnancies occurred through IVF when day-3 FSH exceeded 17 mIU/mL and estradiol exceeded 45 pg/mL, and combining the two markers improved the ability to predict outcomes beyond either alone.5PubMed. Day 3 estradiol serum concentrations as prognosticators of ovarian stimulation response and pregnancy outcome in patients undergoing in vitro fertilization
FSH testing is older and less precise than AMH for gauging the egg pool, but it remains part of many standard fertility evaluations, especially when combined with estradiol and AFC. Think of it as one angle on a picture that needs multiple views to come into focus.
What the Numbers Mean by Age
AMH values follow a predictable downward slope. A large cohort study of nearly 23,000 women found that median AMH dropped from around 3.03 ng/mL at age 25 to about 0.31 ng/mL by age 44.6PubMed. Population-based age-specific reference percentiles and Z-scores for AMH in women Another study of a similar size reported that by age 36, the median AMH had already fallen below 1.2 ng/mL, and the proportion of women classified as having diminished ovarian reserve climbed from about 16% at age 18 to nearly 96% by age 45.7PubMed Central. Age-stratified anti-Müllerian hormone (AMH) nomogram: a comprehensive cohort study including 22.920 women
These are population medians. They tell you where you stand compared to other women your age, not where you stand in absolute terms. An AMH of 1.0 ng/mL means something different at 28 than it does at 40. Age-specific reference charts exist precisely for this reason, and your doctor should interpret your result relative to your age rather than against a single universal cutoff.
Women with short menstrual cycles may see signals of lower reserve earlier. In one study of women with primary infertility, those with short cycles had the lowest average AMH, the lowest AFC, and the highest FSH, with over half classified as having diminished reserve.8Link Medical Journal. Ovarian Reserve Markers and Menstrual Pattern in Women Presenting with Primary Infertility Cycle length changes can be an early clue that reserve is shifting.
What These Tests Cannot Tell You
Here is the part that trips people up most: a low AMH or low AFC does not mean you cannot get pregnant naturally. Ovarian reserve tests measure how many eggs you have left and how your ovaries might respond to fertility medications. They do not measure egg quality, and they do not predict your odds of conceiving without assistance in any given month.
A study comparing women with unexplained infertility to women whose partners had male-factor infertility found that low AMH (below 0.7 ng/mL) showed up at similar rates in both groups. The odds ratio for infertility in women with low AMH was not statistically significant, and when the researchers used an even stricter cutoff of 0.5 ng/mL, the direction actually ran counter to what you’d expect: low AMH was slightly more common in the male-factor group.9PubMed Central. Ovarian reserve does not influence natural conception: insights from infertile women Put plainly, a low egg count did not make natural conception less likely in that population.
This is genuinely confusing for most people, and the marketing around fertility testing often makes it worse. A review of 27 websites selling direct-to-consumer AMH tests found that about three-quarters stated the test could indicate the likelihood of conceiving, while only a third explicitly noted that AMH cannot accurately predict your chances of getting pregnant.10PubMed Central. Websites Selling Direct-to-Consumer Anti-Mullerian Hormone Tests About 41% of the sites suggested you could use the result to adjust your reproductive timeline, and 30% linked it to whether egg freezing was a viable option. The gap between what the science supports and what the marketing implies is real.
Where these tests do have strong predictive value is in the context of IVF or egg freezing. If you’re going through ovarian stimulation, AMH and AFC reliably predict how many eggs your ovaries will produce in a given cycle. That number in turn affects live birth rates per cycle of egg cryopreservation.11Obstetrics & Gynecology. A Novel Counseling Tool: AMH as a Predictor of Oocyte Yield and Live Birth Rate (LBR) With Oocyte Cryopreservation (OC) So the tests are useful for treatment planning, just not for predicting whether you’ll conceive on your own.
Factors That Can Skew Your Results
If you’re testing AMH, several things can artificially push the number up or down, and you should know about them before reading too much into a single result.
Hormonal contraceptives are probably the biggest practical confounder. Women taking the combined oral contraceptive pill had AMH levels roughly 24% lower than women not using any contraception.12American Journal of Obstetrics and Gynecology. Impact of contraceptives on anti-Müllerian hormone levels among reproductive-age women That suppression is temporary. After stopping the pill, AMH levels climbed by an average of 53% within three months, and AFC increased by about 41% over the same period.13PubMed. Ovarian reserve markers after discontinuing long-term use of combined oral contraceptives If you have your AMH tested while on the pill, the result could look significantly worse than it actually is. Many clinics recommend testing at least two to three months after stopping hormonal contraception for this reason.
Cycle timing matters more than some people think. While AMH is marketed as a “test any day” hormone, a meta-analysis found that levels varied about 11.5% across the menstrual cycle, running higher in the follicular phase than the luteal phase.14PubMed Central. Does Anti-Müllerian hormone vary during a menstrual cycle? A systematic review and meta-analysis For most women, that fluctuation won’t change the clinical interpretation dramatically, but it can push a borderline result across a threshold. The issue is more pronounced in younger women, where random fluctuations tend to be larger in absolute terms.15Reproductive BioMedicine Online. Intra-individual variation of anti-Müllerian hormone in women with regular cycles: a re-analysis A single AMH measurement in a 25-year-old should be interpreted cautiously if it comes back unexpectedly low.
Smoking is another factor. Current smokers in one study had AMH values 44% lower than women with no active or passive smoke exposure, though former smokers did not show the same reduction, suggesting the effect may reflect a direct impact on growing follicles rather than permanent damage to the underlying egg reserve.16PubMed Central. The impact of smoking on antimüllerian hormone levels in women aged 38 to 50 years Other research has had trouble replicating the exact magnitude of this association, though the link between smoking and earlier menopause is well established and supports the idea that smoking accelerates ovarian aging in some way.17PubMed Central. Association between cigarette smoking and ovarian reserve among women seeking fertility care
When AMH Reads Unusually High
Most people worry about a low result, but an unusually high AMH can also be clinically meaningful. Polycystic ovary syndrome (PCOS) is the most common reason for an elevated AMH level. The condition is associated with a large number of small antral follicles that produce AMH but often fail to ovulate normally.18PubMed Central. Antimüllerian hormone levels and IVF outcomes in polycystic ovary syndrome women: a scoping review In one study comparing IVF patients with and without PCOS, the PCOS group had a median AMH of about 7.6 ng/mL versus roughly 5.9 ng/mL in the non-PCOS group.19PubMed Central. IVF outcome with a high level of AMH: a focus on PCOS versus non-PCOS
A very high AMH in a woman with PCOS does not mean she has an abundance of readily usable eggs. It means her ovaries contain many follicles that tend to stall during development. In the context of IVF, this also raises the risk of ovarian hyperstimulation syndrome, where the ovaries overreact to fertility medications. Nearly half of the direct-to-consumer AMH testing websites reviewed in one study mentioned that PCOS could falsely inflate AMH, but only about a third noted that the test couldn’t accurately predict chances of conceiving.10PubMed Central. Websites Selling Direct-to-Consumer Anti-Mullerian Hormone Tests If your AMH comes back surprisingly high, PCOS should be on the list of things your doctor evaluates.
Surgery, Chemotherapy, and Other Medical Causes of Low Reserve
Ovarian reserve can be reduced by medical interventions as well as natural aging. Endometriosis surgery is one of the more common culprits. When endometriomas (cysts caused by endometriosis) are removed from the ovaries, some healthy ovarian tissue inevitably comes with them. In one study, average AMH dropped from about 3.2 ng/mL before cystectomy to about 1.9 ng/mL afterward.20Middle Black Sea Journal of Health Science. Surgical removal of endometriomas adversely affects ovarian reserve: Comparison of serum FSH, AMH and AFC before and after cystectomy That’s a substantial drop from a single procedure. Women facing this surgery should discuss the potential impact on future fertility with their surgeon before going ahead.
Certain chemotherapy drugs are known to damage ovarian tissue directly, and the effect can range from temporary disruption to permanent loss of ovarian function depending on the drug, dose, and the patient’s age at treatment. Pelvic radiation carries similar risks. Women who need gonadotoxic treatment are often counseled about fertility preservation options like egg or embryo freezing beforehand, precisely because ovarian reserve testing after treatment may show dramatic declines.
Genetics and the Ovarian Reserve You Start With
Some women are genetically predisposed to a smaller or faster-depleting egg pool. Research has linked mutations in the BRCA1 and BRCA2 genes, better known for their role in breast and ovarian cancer risk, to lower ovarian reserve and earlier menopause. Women carrying these mutations show lower ovarian volumes and increased DNA damage in their eggs over time.21PubMed Central. Genetic determination of the ovarian reserve: a literature review One study investigating the overlap between BRCA mutations and another gene called FMR1 found that certain genetic combinations were dramatically overrepresented among BRCA carriers, suggesting a complex interplay between these genes in determining who starts with what kind of ovarian reserve.22PLoS ONE. BRCA1/2 Mutations Appear Embryo-Lethal Unless Rescued by Low (CGG n<26) FMR1 Sub-Genotypes: Explanation for the “BRCA” Paradox?
Family history can also be informative in a less precise way. If your mother or older sisters went through menopause earlier than average, you may have a genetically lower starting reserve. This is not guaranteed, and there is no reliable genetic test that tells you exactly how many eggs you have, but it’s worth mentioning to your doctor when discussing fertility timing.
Vitamin D and AMH
You may come across claims that vitamin D levels affect AMH and, by extension, your egg count. The evidence here is complicated. One study of women with diminished ovarian reserve who took vitamin D supplements found no significant change in their AMH, AFC, or FSH levels afterward.23PubMed Central. Effects of vitamin D supplementation on ovarian reserve markers in infertile women with diminished ovarian reserve But a broader meta-analysis suggested that the direction of the effect depends on whether a woman ovulates normally: vitamin D supplementation appeared to slightly increase AMH in ovulatory women without PCOS while slightly decreasing it in anovulatory women with PCOS.24PubMed Central. The Association between Vitamin D and Anti-Müllerian Hormone: A Systematic Review and Meta-Analysis
What this probably means is that vitamin D may influence the AMH reading without necessarily changing the actual number of eggs in your ovaries. It may affect how follicles produce AMH rather than how many follicles exist. Either way, taking vitamin D supplements is not a reliable strategy for improving your ovarian reserve numbers in a meaningful clinical sense.
The Emotional Side of Testing
Getting a number attached to your fertility can hit harder than people expect. Qualitative research interviewing women who received AMH results found that the number had a significant impact on lifestyle decisions, relationship dynamics, and even how women felt about their identity.25PubMed. “So what happens next?” exploring the psychological and emotional impact of anti-Mullerian hormone testing A low result triggered urgency and anxiety. A high result sometimes led to false reassurance. Both reactions can be out of proportion to what the test actually measures, especially since, as discussed earlier, AMH does not predict natural conception.
If you’re considering testing, particularly through an at-home kit without a clinician to walk you through the results, it’s worth preparing yourself for the possibility that the number will feel more definitive than it is. Having a follow-up appointment with a reproductive endocrinologist already on the calendar before you get results can help. Context from someone who interprets these numbers daily is worth more than a reference range printed on a lab report.
At-Home Kits Versus Clinical Testing
Direct-to-consumer AMH tests have become widely available. They typically involve a finger-prick blood sample mailed to a lab, with results returned online. The test itself uses the same underlying assay technology as a clinic would, so the measurement is not inherently less accurate. The issue is interpretation. A clinic-ordered panel usually includes AMH, AFC, and day-3 FSH together, giving a three-dimensional view. An at-home kit gives you one number, stripped of context.
The review of 27 direct-to-consumer AMH testing websites found that while 93% included a description of the test and 96% mentioned it could indicate ovarian reserve, the information about limitations was far less consistent.10PubMed Central. Websites Selling Direct-to-Consumer Anti-Mullerian Hormone Tests Some used language designed to promote empowerment and control, framing the test as a proactive health decision. There is nothing wrong with proactive health decisions, but the framing can imply a level of predictive power the test simply does not have when it comes to natural fertility.
If cost or access is a barrier to clinical testing, an at-home AMH kit can be a reasonable starting point, as long as you treat the result as a conversation starter with a doctor rather than a definitive answer. And remember the contraceptive caveat: if you’re on the pill when you take the test, your number could read substantially lower than your actual reserve.
Why Humans Run Out of Eggs at All
From an evolutionary standpoint, it’s a bit strange that human women lose the ability to reproduce decades before the rest of the body wears out. Most other mammals remain fertile until very near the end of their lifespan. The leading explanation, sometimes called the grandmother hypothesis, proposes that women who stopped reproducing at a certain age and redirected their energy toward helping raise grandchildren actually passed on more of their genes than women who kept having children into old age.26PubMed. The evolution of premature reproductive senescence and menopause in human females: An evaluation of the “grandmother hypothesis” Another possibility is simpler: human lifespans have increased faster than the ovarian supply has had time to evolve to keep pace. Researchers have debated these ideas for decades without reaching full consensus, but either way, the practical upshot is the same. The egg supply is fixed, it declines with age, and the tests described above are the best tools currently available for estimating where you stand.