Ovarian Reserve Testing: AMH, Antral Follicle Count Explained

What is ovarian reserve, and why does it matter?

Women and those assigned female at birth are born with all the eggs they will ever have. This pool declines throughout life — accelerating in the mid-to-late 30s — and diminishes entirely at menopause. Ovarian reserve testing estimates where someone is on that trajectory at the time of testing.

In a fertility context, lower ovarian reserve generally means 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Describes the role of AMH, AFC, FSH, and estradiol in the standard fertility evaluation; interpretation of results in the context of age and clinical picture; implications of diminished ovarian reserve: - Fewer eggs available to retrieve in an IVF cycle - Potentially a shorter window of natural fertility - A signal to discuss timelines with a reproductive endocrinologist sooner rather than later

Importantly, ovarian reserve reflects quantity, not guaranteed quality. A person with a low AMH can still have chromosomally normal eggs — reserve testing tells you about the size of the pool, not the quality of every egg in it.

What does the AMH test measure?

AMH (anti-Müllerian hormone) is produced by the small follicles in the ovaries. Because these small (pre-antral and antral) follicles reflect the pool from which eggs are drawn each cycle, AMH level correlates with the number of remaining follicles 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Describes the role of AMH, AFC, FSH, and estradiol in the standard fertility evaluation; interpretation of results in the context of age and clinical picture; implications of diminished ovarian reserve.

Practical features: - Can be drawn at any point in the menstrual cycle (does not need to be timed to day 2–3) - Results are relatively consistent from cycle to cycle - Reported in ng/mL or pmol/L depending on the laboratory

Interpreting results: Laboratory reference ranges vary, and 'normal' varies by age. An AMH that would be considered reassuring at 38 may be concerning at 28. Your clinician will interpret your result in the context of your age and full clinical picture 3Ref 3Practice Committee of the American Society for Reproductive Medicine (2020).Testing and interpreting measures of ovarian reserve: a committee opinion.Comprehensive review of ovarian reserve test performance: AMH, AFC, FSH, and estradiol — their cycle-independence, consistency, and complementary roles; AFC as a reasonable alternative to AMH when performed by experienced sonographer. A single AMH value is never a definitive statement about whether pregnancy is possible — it is one data point in a broader evaluation.

What is the antral follicle count?

The antral follicle count (AFC) is performed by transvaginal ultrasound, typically in the early follicular phase (days 2–5 of the cycle). The clinician counts all small follicles (usually 2–10 mm) visible in both ovaries. These antral follicles represent the pool of follicles available to respond to stimulation in a given cycle.

AFC correlates with AMH and is used alongside it in fertility evaluation 3Ref 3Practice Committee of the American Society for Reproductive Medicine (2020).Testing and interpreting measures of ovarian reserve: a committee opinion.Comprehensive review of ovarian reserve test performance: AMH, AFC, FSH, and estradiol — their cycle-independence, consistency, and complementary roles; AFC as a reasonable alternative to AMH when performed by experienced sonographer: - A higher AFC generally predicts a more robust response to ovarian stimulation in IVF - A low AFC (typically fewer than 5–7 total across both ovaries, though thresholds vary by clinic) may indicate diminished reserve - A high AFC — particularly in the setting of small, peripherally distributed follicles and elevated AMH — is one diagnostic criterion for polycystic ovary syndrome (PCOS) 2Ref 2Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group (2004).Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome (PCOS).Polycystic ovarian morphology on ultrasound (multiple small peripherally distributed follicles) as a diagnostic criterion for PCOS; relevant to interpreting high AFC and elevated AMH in that context

When performed by an experienced sonographer, AFC is considered a reasonable alternative to AMH, and the two tests generally provide complementary information 3Ref 3Practice Committee of the American Society for Reproductive Medicine (2020).Testing and interpreting measures of ovarian reserve: a committee opinion.Comprehensive review of ovarian reserve test performance: AMH, AFC, FSH, and estradiol — their cycle-independence, consistency, and complementary roles; AFC as a reasonable alternative to AMH when performed by experienced sonographer.

What about FSH and estradiol?

Before AMH became widely available, FSH (follicle-stimulating hormone) measured on day 3 of the cycle was the standard ovarian reserve test. An elevated FSH (the pituitary working harder to stimulate declining ovaries) indicated diminished reserve. Estradiol on the same day was measured to ensure the FSH reading was not falsely suppressed by an early dominant follicle 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Describes the role of AMH, AFC, FSH, and estradiol in the standard fertility evaluation; interpretation of results in the context of age and clinical picture; implications of diminished ovarian reserve.

FSH and estradiol remain useful and are still ordered in many fertility evaluations. They are more cycle-dependent than AMH and can vary between cycles, so a single reassuring result does not rule out diminished reserve if other signs are present. When FSH and estradiol conflict with AMH or AFC, the full picture is discussed with a specialist 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Describes the role of AMH, AFC, FSH, and estradiol in the standard fertility evaluation; interpretation of results in the context of age and clinical picture; implications of diminished ovarian reserve3Ref 3Practice Committee of the American Society for Reproductive Medicine (2020).Testing and interpreting measures of ovarian reserve: a committee opinion.Comprehensive review of ovarian reserve test performance: AMH, AFC, FSH, and estradiol — their cycle-independence, consistency, and complementary roles; AFC as a reasonable alternative to AMH when performed by experienced sonographer.

What happens if tests suggest diminished ovarian reserve?

Diminished ovarian reserve does not mean pregnancy is impossible. It means 1Ref 1Practice Committee of the American Society for Reproductive Medicine (2021).Fertility evaluation of infertile women: a committee opinion.Describes the role of AMH, AFC, FSH, and estradiol in the standard fertility evaluation; interpretation of results in the context of age and clinical picture; implications of diminished ovarian reserve: - Time may matter more — acting sooner rather than later gives access to more of the remaining egg pool - IVF success rates are lower with diminished reserve, because fewer eggs are retrieved per cycle - Cumulative success across multiple cycles may still be meaningful, depending on how low the reserve is - Options such as egg donation (using another person's eggs) may be discussed depending on severity and goals

The conversation is highly individual. A reproductive endocrinologist can translate test results into realistic, personalized guidance — including what retrieval cycle yield to expect and how that translates into cumulative success probability.