Interpreting AMH, FSH, LH, and E2 Results
The pattern of these hormone levels together is far more diagnostically valuable than any single absolute value, and you must interpret them in the context of clinical presentation to distinguish between functional hypothalamic amenorrhea, ovarian insufficiency, PCOS, and normal cycling 1.
Key Diagnostic Patterns
Functional Hypothalamic Amenorrhea (FHA)
- LH: <10 IU/L (low or low-normal)
- FSH: <10 IU/L (normal, typically higher than LH)
- LH/FSH ratio: ~1
- E2: <50 pg/mL
- AMH: >1 ng/mL
- Clinical context: Energy deficit, excessive exercise, stress, low body weight 1
Primary Ovarian Insufficiency/Menopause
- LH: >15 IU/L (elevated)
- FSH: >15 IU/L (elevated, FSH > LH)
- E2: <50 pg/mL (often <20 pg/mL)
- AMH: <0.5 ng/mL
- Key distinction: Both gonadotropins are elevated, reflecting loss of ovarian feedback 1
Polycystic Ovary Syndrome (PCOS)
- LH: <15 IU/L but elevated relative to FSH
- FSH: <10 IU/L (normal or low-normal)
- LH/FSH ratio: LH > FSH (reversed ratio)
- E2: <50 pg/mL
- AMH: Normal or elevated (often >4-5 ng/mL)
- Clinical context: Hyperandrogenism, oligo-ovulation 1, 2
Critical Interpretation Points
AMH as an Ovarian Reserve Marker
AMH correlates most strongly with antral follicle count (r=0.74) and is superior to FSH, LH, E2, or inhibin B for assessing ovarian follicular status 3. AMH shows the strongest negative correlation with age (r=-0.931) among all ovarian reserve markers 4.
Important caveats about AMH:
- AMH reflects follicle pool size but does NOT predict spontaneous pregnancy potential in individual cases 5
- In FHA with polycystic ovarian morphology, AMH may be paradoxically elevated despite hypothalamic suppression, then decrease after recovery 6
- AMH >6-7 ng/mL strongly suggests PCOS when combined with appropriate clinical features 2, 6
FSH and LH Interpretation Pitfalls
Beware of "normal" FSH and LH in the setting of low E2 - this represents inappropriate gonadotropin response and indicates hypothalamic dysfunction, not normal ovarian function 1. Truly normal ovaries would produce elevated FSH/LH in response to low estrogen.
Very low or undetectable LH and FSH (<2-3 IU/L) with low E2 suggests organic hypothalamic amenorrhea from genetic mutations affecting GnRH, pituitary/hypothalamic tumors, or infiltrative lesions - this requires MRI evaluation 1.
E2 Measurement Limitations
- E2 represents a single time point and fluctuates throughout the cycle 1, 7
- E2 <20 pg/mL persistently indicates severe hypoestrogenism
- E2 >150 pg/mL with elevated FSH/LH may represent mid-cycle surge, not pathology 1
- Assay quality matters - follow Endocrine Society guidelines for reliable E2 measurement 1
Algorithmic Approach to Interpretation
Step 1: Check FSH and LH levels
- Both elevated (>15 IU/L) → Ovarian insufficiency (confirm with AMH <0.5-1.0 ng/mL)
- Both low (<10 IU/L) with low E2 → Hypothalamic dysfunction
- Very low/undetectable → Organic hypothalamic/pituitary pathology (order MRI)
- LH > FSH → Consider PCOS (check AMH, androgens)
Step 2: Correlate with AMH
- AMH <0.5-1.0 ng/mL → Diminished ovarian reserve regardless of age
- AMH >4-6 ng/mL → Suggests PCOS or polycystic ovarian morphology
- AMH 1-4 ng/mL → Normal range (age-dependent)
Step 3: Integrate E2 levels
- E2 <20 pg/mL persistently → Severe hypoestrogenism requiring intervention
- E2 <50 pg/mL with low-normal FSH/LH → FHA pattern
- E2 <50 pg/mL with elevated FSH/LH → Ovarian insufficiency
Step 4: Consider clinical context
- Menstrual pattern (amenorrhea, oligomenorrhea, regular cycles)
- Signs of hyperandrogenism (acne, hirsutism)
- Body weight, exercise patterns, stress
- Age and reproductive goals
Common Diagnostic Errors to Avoid
Do not diagnose PCOS based solely on elevated AMH - you need clinical or biochemical hyperandrogenism plus ovulatory dysfunction 2. AMH can be elevated in FHA with polycystic ovarian morphology without true PCOS 6.
Do not reassure patients with "normal" FSH/LH when E2 is low - this represents hypothalamic suppression, not normal function 1.
Do not use AMH alone to counsel about fertility potential - women with negligible AMH (<0.1 ng/mL) can still achieve spontaneous pregnancy 5. AMH reflects follicle pool, not oocyte quality or pregnancy potential.
Timing matters for cycling women - ideally measure on cycle day 2-5 (early follicular phase) for baseline assessment 7, 8. Random measurements are difficult to interpret.