What additional parameters besides anti‑Müllerian hormone are used to assess ovarian reserve and how do they function?

Ovarian Reserve Assessment Parameters Beyond AMH

Besides anti-Müllerian hormone, antral follicle count (AFC) by transvaginal ultrasound is the most established method for assessing ovarian reserve, with baseline FSH and estradiol serving as secondary markers measured on cycle days 3-6. 1, 2

Primary Assessment Tools

Antral Follicle Count (AFC)

• AFC by transvaginal ultrasound directly visualizes the pool of small antral follicles (2-6 mm diameter) available for recruitment, providing a comprehensive evaluation of ovarian reserve. 1, 2
• AFC shows a strong positive correlation with AMH levels (r=0.77), making it comparable in predictive value. 3, 4
• For women under 25 years, AFC remains the gold standard since AMH interpretation is less reliable in this age group. 1

Key limitation: AFC is operator and equipment-dependent, limiting accuracy and reproducibility, and requires expensive equipment and trained personnel. 2

How AFC Works

• The test counts all visible follicles measuring 2-6 mm in both ovaries during the early follicular phase (days 3-6). 1
• The number of antral follicles directly reflects the remaining pool of primordial follicles that can be recruited for ovulation. 3
• Lower AFC indicates diminished ovarian reserve and predicts poor response to ovarian stimulation. 3

Secondary Hormonal Markers

Follicle-Stimulating Hormone (FSH)

• Baseline FSH should be measured on days 3-6 of the menstrual cycle for women with regular cycles. 1
• FSH >35 IU/L suggests ovarian failure, but FSH is a late marker of ovarian dysfunction and less sensitive than AMH for early detection of diminished ovarian reserve. 1
• FSH shows only modest correlation with AFC (r=-0.299) and age (r=-0.400), making it inferior to AMH and AFC. 4, 5

How FSH works: As ovarian reserve declines, reduced inhibin B and estradiol production from fewer follicles leads to loss of negative feedback on the pituitary, causing compensatory FSH elevation. 1

Estradiol (E2)

• Baseline estradiol should be measured on days 3-6 alongside FSH. 1
• Estradiol shows positive correlation with age (r=0.638) and negative correlation with AFC (r=-0.543). 5
• Elevated baseline estradiol (>60-80 pg/mL) can artificially suppress FSH, masking diminished ovarian reserve—a common pitfall. 6

How estradiol works: Early follicular phase estradiol reflects the activity of developing follicles; elevated levels suggest premature follicle recruitment due to declining reserve. 6

Inhibin B

• Inhibin B shows strong negative correlation with age (r=-0.878) and positive correlation with AFC (r=0.769). 5
• However, inhibin B shows no significant correlation with AFC in some studies (r=0.154, p=0.06), making it less reliable than AMH. 4

How inhibin B works: Produced by granulosa cells of small antral follicles, inhibin B levels reflect the functional follicle pool and provide negative feedback on FSH secretion. 6, 5

Ovarian Volume

• Ovarian volume measured by ultrasound shows strong negative correlation with age (r=-0.876) and positive correlation with AFC (r=0.919). 5
• Ovarian volume declines as the follicle pool diminishes with age. 5

Clinical Application Algorithm

For Women ≥25 Years with Regular Cycles

• Begin with AMH testing as the preferred initial assessment, then add AFC for comprehensive evaluation. 1
• If AMH <0.7 ng/mL, this indicates severely diminished ovarian reserve or incipient ovarian failure. 1, 7
• Consider baseline FSH and estradiol on days 3-6 if AMH and AFC results are discordant. 1

For Women <25 Years

• Use AFC by transvaginal ultrasound as the gold standard, since AMH interpretation is unreliable in this age group. 1
• AMH levels can fluctuate throughout the menstrual cycle in young women, limiting clinical utility. 2

For Women with Irregular Cycles or Amenorrhea

• AMH is particularly useful since it does not require cycle-specific timing and can be measured at any point. 1
• AFC may be difficult to interpret without regular menstrual cycles. 1

Important Caveats

• AMH assays lack international standardization, so results must be interpreted using laboratory-specific reference ranges. 1, 2
• Persistence of regular menstruation after gonadotoxic treatment does not guarantee normal ovarian reserve—women who resume menses often have compromised ovarian reserve and reduced fertility. 8
• In cancer survivors treated with alkylating agents or radiotherapy, AMH serves as a promising biomarker to predict remaining ovarian reserve and estimate timing of menopause onset. 1
• Multiple regression models combining AFC, inhibin B, and ovarian volume provide the best prediction of ovarian response, but AMH alone performs comparably in clinical practice. 6