The Role of Anti-Müllerian Hormone (AMH) in Assessing Ovarian Reserve and Fertility
AMH is currently the best available biomarker for assessing ovarian reserve, providing valuable information about the quantity of remaining follicles, but it does not predict oocyte quality or pregnancy outcomes. 1, 2
What is AMH?
- AMH is exclusively produced by granulosa cells of ovarian follicles during early stages of follicle development
- Secreted primarily by preantral and small antral follicles (2-8mm)
- After an initial increase until early adulthood, AMH levels gradually decline with age until becoming undetectable approximately 5 years before menopause 3
Clinical Value of AMH in Assessing Ovarian Reserve
Advantages of AMH Testing
- Reflects the size of the primordial follicle pool and antral follicle count
- Shows less cycle-to-cycle variability than other hormonal markers
- Can be measured at any point in the menstrual cycle (though some fluctuations may occur) 3, 4
- Provides earlier indication of declining ovarian reserve than FSH or estradiol 5
Interpretation of AMH Levels
- Wide range of normal values exists for women of the same chronological age
- Decreasing levels indicate diminishing ovarian reserve
- In women ≥25 years, AMH is inversely correlated with age, implying clinical utility as a marker of ovarian reserve 1
- Low AMH levels may suggest a shortened reproductive window but do not necessarily predict infertility 2
Clinical Applications of AMH Testing
Fertility Assessment
- Helps predict ovarian response to stimulation in assisted reproductive technologies
- Useful for individualizing gonadotropin dosing protocols for IVF 3
- Not recommended as a standalone fertility test for the general population 2
- Does not predict chances for natural conception or live birth 2
Monitoring Gonadotoxic Treatment Effects
- Valuable for assessing ovarian function in cancer survivors
- Can distinguish women with premature ovarian insufficiency (POI) who have few/no follicles from those at risk for POI but still have a reasonably sized follicle pool 1
- May be of additive value for survivors treated with alkylating agents and/or radiotherapy affecting the ovaries 1
Diagnosis of Reproductive Disorders
- Helpful in diagnosing polycystic ovary syndrome (PCOS)
- Can aid in identifying premature ovarian insufficiency
- May help distinguish between different causes of amenorrhea 6, 5
Limitations and Considerations
Interpretation Challenges
- AMH should not be used alone to withhold fertility treatment 2
- Significant individual variability exists in AMH levels
- Low levels in young women require careful interpretation 1
- Extra caution needed when interpreting AMH values in women under 25 years 1
Factors Affecting AMH Levels
- Hormonal contraceptive use may lower AMH without reflecting true ovarian reserve
- Hypogonadotropic hypogonadism can artificially lower AMH levels 4, 2
- Inverse correlation between body mass index and AMH 2
- PCOS often associated with elevated AMH levels 5
Technical Considerations
- Lack of international standardization of AMH assays
- Different storage and handling techniques may affect results 3
Clinical Recommendations
- AMH should be used as part of a comprehensive fertility evaluation, not in isolation
- May be used as an adjunctive test in women ≥25 years with menstrual dysfunction 6
- For cancer survivors treated with gonadotoxic therapies, AMH can help assess risk of premature ovarian insufficiency 1
- When evaluating irregular menstrual cycles, consider AMH alongside FSH, LH, estradiol, and other hormonal tests 6
- For women considering fertility preservation or family planning, AMH provides information about remaining reproductive lifespan but should be interpreted with age as the primary factor 2
In conclusion, while AMH is a valuable tool for assessing ovarian reserve, it should be interpreted within the clinical context, considering the patient's age, medical history, and other fertility markers. It primarily reflects follicle quantity rather than quality and cannot independently predict natural fertility outcomes.