Normal AMH for a 40-Year-Old Woman
For a 40-year-old woman, normal AMH levels typically range from approximately 0.5 to 3.0 ng/mL (or roughly 3.5 to 21 pmol/L), though values decline progressively with age and show considerable individual variation.
Age-Specific Reference Ranges
The evidence consistently demonstrates that AMH levels decline exponentially with advancing age. Multiple large population-based studies provide specific reference ranges for women around age 40:
Chinese population study (n=1,590): Women aged 37-40 years showed median AMH of 2.78 ng/mL with a reference range (5th-95th percentile) of 0.56-9.49 ng/mL 1
Another Chinese cohort (n=1,423): Women aged 36-40 years had median AMH of 1.07 µg/L (approximately 1.07 ng/mL) 2
Omani population study (n=319): Women aged 36-40 years showed median AMH of 13.71 pmol/L (approximately 1.92 ng/mL) with reference range of 2.15-48.91 pmol/L (0.30-6.86 ng/mL) 3
Korean infertility clinic data (n=16,972): Women aged 38-40 years had median AMH of 0.96 ng/mL 4
Key Clinical Considerations
AMH interpretation must account for multiple factors:
Assay variability: Different AMH assays (Gen II ELISA, Beckman Coulter, Elecsys Roche) produce different absolute values, making universal cut-offs problematic 5, 6
Population differences: Ethnic and geographic variations exist in AMH reference ranges, as demonstrated by differences between Chinese, Omani, and Korean populations 3, 1
Clinical context matters: AMH below 0.7-1.0 ng/mL is consistently associated with diminished ovarian reserve and increased miscarriage risk in women ≥35 years (OR 1.91-2.11) 7
Practical Interpretation Framework
For a 40-year-old woman:
AMH <0.5 ng/mL: Indicates significantly diminished ovarian reserve; associated with reduced fertility and higher miscarriage risk 7
AMH 0.5-3.0 ng/mL: Generally within expected range for age, though lower end suggests declining reserve
AMH >3.0 ng/mL: Above typical median for age 40; may suggest better ovarian reserve or possible polycystic ovarian morphology if accompanied by other features
Important Caveats
AMH should not be used in isolation. The 2023 international PCOS guidelines emphasize that AMH alone is insufficient for diagnosis and must be interpreted alongside clinical features, menstrual history, and ultrasound findings when indicated 5, 6.
Wide normal ranges exist. The 95th percentile values can be 10-15 times higher than 5th percentile values at any given age, reflecting substantial biological variability 3, 1. A single AMH value provides information about ovarian reserve but cannot predict individual fertility outcomes with certainty 8.
Menstrual cycle timing: While AMH is relatively stable across the menstrual cycle in older women, some fluctuation can occur, particularly in younger women 9.