What is Anti-Müllerian Hormone (AMH)?

What is Anti-Müllerian Hormone (AMH)?

AMH is a dimeric glycoprotein hormone secreted by granulosa cells of pre-antral and small antral ovarian follicles that serves as a biomarker of the ovarian follicle pool and ovarian reserve. 1

Biological Function and Production

• AMH is a member of the transforming growth factor-β (TGF-β) superfamily produced exclusively in the gonads 2, 3
• In females, AMH is secreted by granulosa cells of growing follicles from the primary follicular stage through the small antral stage, but production ceases once follicles reach the dominant stage 2, 4
• AMH inhibits primordial follicle recruitment from the resting pool and suppresses FSH-induced follicle growth, thereby regulating the pace of follicular development 1, 4
• Serum AMH levels directly reflect both the quantity and quality of the remaining ovarian follicle pool throughout a woman's reproductive lifespan 2, 3

Clinical Significance as a Biomarker

• AMH is the most reliable marker of ovarian reserve in women ≥25 years, where it inversely correlates with age and provides information about remaining reproductive lifespan 5
• Unlike other ovarian hormones (FSH, estradiol), AMH levels remain relatively stable throughout the menstrual cycle, making it a convenient marker that can be measured at any time 3
• AMH levels gradually decline with age as the ovarian follicle pool diminishes, eventually falling below detectable levels at menopause 3, 6
• AMH strongly correlates with antral follicle count (AFC) visualized on ultrasound, serving as a biochemical surrogate for this imaging marker 3

Key Clinical Applications

Ovarian Reserve Assessment:

• The American Society for Reproductive Medicine recommends AMH as a clinically useful marker of ovarian reserve in women ≥25 years 5
• AMH can predict poor ovarian response to stimulation in assisted reproductive technology (ART) and help establish patient profiles before IVF 6
• AMH may predict time to menopause in women in their 40s 7

PCOS Evaluation:

• Serum AMH levels are significantly higher in women with PCOS compared to those with normal ovulatory function 1
• AMH serves as a potential alternative or adjunct to ultrasound for detecting polycystic ovarian morphology, particularly when ultrasound is not accessible 5
• However, the Endocrine Society emphasizes that AMH should not yet replace established PCOS diagnostic criteria due to significant overlap in AMH levels between women with and without PCOS 5, 1

Post-Treatment Assessment:

• AMH is recommended for evaluating ovarian reserve in cancer survivors treated with alkylating agents and/or radiotherapy 5
• AMH levels reflect the effects of damaging gynecologic surgeries or gonadotoxic treatments on ovarian reserve 6

Important Clinical Limitations

• AMH does NOT predict natural fertility: Despite being a marker of ovarian reserve, multiple large studies including over 1,200 women confirmed that AMH levels do not predict time-to-pregnancy or fecundability in the general population 7
• Not for routine preconception counseling: AMH should NOT be used routinely for preconception counseling in young, fertile women under 25 years due to limited value and potential fluctuations 5
• Not for PCOS diagnosis in adolescents: AMH must NOT be used for PCOS diagnosis in adolescents within 8 years of menarche due to overlap with normal physiological values 5, 1
• Lack of standardization: The absence of an international standard for AMH limits comparison between different assays, and direct comparison of results remains problematic 5, 6
• Assay variability: AMH assays display differential responses to pre-analytical factors and show appreciable sample-to-sample variability 5
• Age-specific interpretation required: Age-specific reference ranges are essential when interpreting AMH levels, as values naturally decline with age 5, 1

Clinical Pitfalls to Avoid

• Do not use AMH as a standalone diagnostic test for any condition—it must be interpreted in clinical context with other markers 5, 1
• Do not counsel patients that low AMH means they cannot conceive naturally, as AMH does not predict natural fertility in the general population 7
• Do not compare AMH results across different laboratory assays without understanding the specific assay used and its reference ranges 5, 6
• Refer at-risk postpubertal females without signs of premature ovarian insufficiency who desire fertility assessment for specialist consultation rather than relying on AMH alone 5