What are normal ranges for Antral Follicle Count (AFC) and Anti-Müllerian Hormone (AMH) levels?

Normal Ranges for AMH and AFC

Based on the available evidence, normal AMH levels range from approximately 1.0-5.6 ng/ml, with values below 0.85-1.1 ng/ml considered low (diminished ovarian reserve), and normal AFC ranges from 7-20 follicles, with counts below 4-6 considered low. 1

Anti-Müllerian Hormone (AMH) Reference Ranges

Low AMH (Diminished Ovarian Reserve)

• Low AMH is defined as <0.85-1.1 ng/ml across multiple studies, with the most commonly used cutoff being <1.0 ng/ml 1
• Severely diminished reserve is characterized by AMH <0.7 ng/ml 1
• These low values are associated with significantly increased miscarriage risk (OR 1.35-1.91) and reduced ovarian response to stimulation 1

Normal/Medium AMH Range

• Normal AMH ranges from approximately 1.0-2.0 ng/ml in most reproductive-age women 1
• The Endocrine Society uses diagnostic thresholds for polycystic ovarian morphology starting at 20-57 pmol/L (approximately 0.14-0.4 ng/ml), with most guidelines using 30-50 pmol/L 2

High AMH

• High AMH is defined as ≥2.0-5.6 ng/ml depending on the study population 1
• AMH levels of 45 pmol/L (approximately 0.32 ng/ml) or 2-3 times higher than age-matched controls are characteristic of PCOS 2

Important Caveats for AMH Interpretation

• AMH demonstrates less inter- and intra-cycle variation (ICC 0.87-0.89) compared to AFC, making it a more reliable single measurement 3
• Combined oral contraceptives can decrease AMH levels by 17-23%, which must be considered when interpreting results 2
• AMH declines with age (r = -0.30, p < 0.001), with typical physiologic variation of 17-23% in young women 2, 4
• When there is discordance between AMH and AFC, AMH has more predictive value for ovarian stimulation success than AFC 5

Antral Follicle Count (AFC) Reference Ranges

Low AFC (Diminished Ovarian Reserve)

• Low AFC is defined as <4-6 follicles (2-10 mm diameter) across both ovaries 1
• This cutoff varies slightly by study, with some using <7 as the threshold 5

Normal/Medium AFC Range

• Normal AFC ranges from 7-15 follicles, with a median of approximately 10 follicles in reproductive-age women 1, 3, 4
• The interquartile range in normo-ovulatory women is typically 7-15 follicles 4

High AFC

• High AFC is defined as ≥15-20 follicles 1
• Higher counts may indicate PCOS or increased ovarian reserve 2

Important Caveats for AFC Interpretation

• AFC shows greater variability than AMH (ICC 0.69-0.71), with measurements ranging from 0-43 follicles even within the same individual across cycles 3
• AFC should be measured on cycle day 2-5 for consistency, counting follicles 2-10 mm in diameter 3, 4
• AFC correlates negatively with age (r = -0.27, p = 0.001) and years since menarche 4
• There is a positive correlation between AMH and AFC (r = 0.54, p < 0.0001), though discordance occurs in approximately 25-35% of cases 5, 4

Clinical Application Algorithm

When assessing ovarian reserve, follow this approach:

1. Measure both AMH and AFC rather than relying on a single marker, as they provide complementary information 5, 6

2. If concordant (both low or both normal): The interpretation is straightforward and reflects true ovarian reserve status 5

3. If discordant: AMH takes precedence for predicting ovarian response, with patients having high AMH/low AFC showing better stimulation outcomes (FORT score 136 vs 71, p<0.01) than those with low AMH/high AFC 5

4. Repeat measurement in 6-12 months if initial values are borderline or if there has been a significant decline (>36%) to establish a trend 2

5. Ensure consistent timing: Measure at the same point in the menstrual cycle (day 2-5) and account for hormonal contraceptive use 2, 3