What it measures.
Anti-Müllerian Hormone (AMH) is produced by granulosa cells of pre-antral and small antral ovarian follicles. It is the most stable serum marker of functional ovarian reserve — the pool of follicles available for ovulation. Unlike FSH or estradiol, AMH is cycle-independent and can be measured on any day, making it the preferred tool for reserve assessment, IVF planning, and menopause prediction.
The functional ovarian reserve: the number of small growing follicles (2-9 mm) available at the time of testing. AMH is gonadotropin-independent — it is not regulated by FSH or LH and is consistent throughout the menstrual cycle.
Why it matters.
AMH is the strongest predictor of ovarian response in IVF, identifies women with lower-than-expected reserve who may benefit from earlier fertility planning, and is now validated as a PCOS diagnostic marker (79% sensitivity, 87% specificity). Very low AMH in women under 40 triggers a primary ovarian insufficiency workup.
Physiology.
AMH is secreted by granulosa cells of developing follicles from the primordial-to-antral stage. It inhibits primordial follicle recruitment and reduces follicular sensitivity to FSH, acting as a 'brake' on follicle depletion. As follicles are consumed over reproductive life, AMH declines progressively with age — from a median of 4.23 ng/mL at age 20-25 to 0.52 ng/mL at age 40-44.
Testing & preparation.
How to prepare
- No fasting required
- Can be drawn on ANY cycle day (major advantage over Day 3 FSH)
- Note if on oral contraceptives — OCPs suppress AMH by ~20-30%
- Results from different assay platforms should not be directly compared
When to test
Any time fertility assessment is desired. Before IVF to predict response. When periods become irregular in women under 40. As part of pre-conception planning at any age.
How often
Every 6-12 months if monitoring reserve decline. Once is sufficient for baseline if normal and no risk factors.
Interpretation.
High anti-müllerian hormone
Common causes:
- PCOS (AMH typically 2-3x above age-matched controls)
- Granulosa cell tumour (rare; AMH used as tumour marker)
- Younger reproductive age (physiologically higher)
Implications:
- AMH >3.4 ng/mL with hyperandrogenism supports PCOS diagnosis
- Risk of ovarian hyperstimulation syndrome (OHSS) in IVF
- Higher antral follicle count
Low anti-müllerian hormone
Common causes:
- Age-related ovarian reserve decline
- Premature ovarian insufficiency (POI) if under 40
- Prior ovarian surgery or cystectomy
- Chemotherapy or radiation gonadotoxicity
- Endometriosis (independently lowers AMH)
- Smoking (independently associated with lower AMH)
Implications:
- May need expedited fertility planning
- Poor IVF response predicted (fewer oocytes retrieved)
- Does NOT mean infertility — women with low AMH can conceive naturally
- AMH <0.5 ng/mL warrants reproductive endocrinologist referral
Optimization.
Diet
- No specific dietary interventions proven to raise AMH
- Mediterranean diet supports overall reproductive health
- Adequate vitamin D — receptors present in granulosa cells
Lifestyle
- Stop smoking — independently associated with lower AMH
- Maintain healthy BMI
- AMH decline is largely age-driven and not modifiable
- Earlier fertility planning is the actionable response to low AMH
Supplements
- DHEA supplementation studied in poor responders (evidence mixed)
- CoQ10 studied for egg quality (not AMH itself)
- Vitamin D repletion if deficient
FAQs.
Does low AMH mean I can't get pregnant?
No. AMH measures egg quantity, not quality. Women with low AMH can and do conceive naturally. However, low AMH means the window may be narrower — there are fewer eggs remaining, so time becomes a factor. It does not predict the quality of the eggs that are left.
Can I test AMH while on birth control?
Yes, but oral contraceptives suppress AMH by approximately 20-30%. The result will be lower than your true baseline. Testing after stopping OCPs gives a more accurate picture, but an on-pill AMH can still identify very low reserve.
How is AMH different from Day 3 FSH?
AMH can be drawn on any cycle day and is more stable — FSH varies cycle to cycle and must be drawn on Days 2-5 with estradiol to be interpretable. AMH reflects the structural reserve (follicle pool size); FSH reflects the functional response (how hard the pituitary works). Both together give the most complete picture.