What are the next steps for a female patient of reproductive age with irregular menstrual cycles, ovaries with increased stroma and few follicles, and a normal Anti-Müllerian Hormone (AMH) level?

Next Steps for Irregular Cycles with Increased Ovarian Stroma, Few Follicles, and Normal AMH

Measure FSH and estradiol levels during the early follicular phase (days 2-5) or randomly if amenorrheic, and refer to gynecology or reproductive endocrinology for comprehensive evaluation of potential premature ovarian insufficiency (POI) or polycystic ovary syndrome (PCOS). 1

Immediate Laboratory Evaluation

Your patient's presentation—irregular cycles with increased ovarian stroma, few follicles, and normal AMH—requires hormonal assessment to differentiate between evolving POI and atypical PCOS:

• Obtain FSH and estradiol levels during early follicular phase (cycle days 2-5) if oligomenorrheic, or randomly if amenorrheic 1
• Discontinue any hormone replacement therapy or oral contraceptives at least 2 months prior to testing, as these interfere with accurate assessment 1
• Consider adding LH and testosterone to the hormonal panel to evaluate for hyperandrogenism, which may be present despite atypical ovarian morphology 2

The normal AMH is reassuring but does not exclude ovarian dysfunction, as AMH primarily reflects the growing follicular pool responsive to gonadotropins rather than the total primordial follicle reserve 3, 4. In women under 25 years, AMH can fluctuate significantly throughout the menstrual cycle, requiring cautious interpretation 1, 5.

Ultrasound Reassessment

Perform transvaginal ultrasound with detailed follicle counting using an 8 MHz or higher frequency transducer to accurately assess ovarian morphology 1:

• Count total follicles per ovary measuring 2-9mm to determine if PCOS criteria are met (≥20 follicles per ovary or ovarian volume ≥10mL) 1
• Measure ovarian volume in three dimensions for each ovary, as volume <3 cm³ with <5 antral follicles suggests diminished ovarian reserve despite normal AMH 1
• Document increased stromal echogenicity, which is the most sensitive and specific ultrasound sign of polycystic ovaries, though subjective 1
• Assess for central stromal vascularity using color Doppler, as increased vascularity is characteristic of PCOS 1

The combination of increased stroma with very few follicles is atypical—classic PCOS shows ≥20 follicles with increased stroma, while POI shows few follicles with normal or decreased stroma 1.

Specialist Referral

Refer to gynecology or reproductive endocrinology for definitive diagnosis and management 1, 2:

• Referral is indicated for menstrual cycle dysfunction suggestive of POI or when fertility assessment is desired 1
• Specialists should perform comprehensive endocrine work-up including FSH, LH, estradiol, AMH, and testosterone 2
• Evaluation should exclude other causes of ovarian insufficiency such as Turner syndrome or autoimmune conditions 1

Clinical Interpretation Framework

The differential diagnosis includes:

Evolving POI: If FSH is elevated (>25-40 mIU/mL depending on laboratory) with low estradiol on two occasions at least one month apart, this confirms POI despite normal AMH 1. Normal AMH does not exclude POI, as AMH only reflects remaining growing follicles, not the depleted primordial pool 3, 4.

Atypical PCOS: If androgens are elevated with normal/low FSH, this suggests PCOS with atypical ovarian morphology 1. The 2014 Androgen Excess and PCOS Society criteria require either ≥25 follicles or ovarian volume ≥10mL, but increased stroma alone with few follicles doesn't meet standard criteria 1.

Hypogonadotropic hypogonadism: If both FSH and LH are low (<1.0 mIU/mL) with low estradiol, this indicates central hypogonadism, where AMH can paradoxically be normal or low and may increase with gonadotropin stimulation 3.

Management Considerations

• Contraception counseling is mandatory even with irregular cycles and few follicles, as spontaneous pregnancy can occur unpredictably 2, 6
• Hormone replacement therapy should be considered if POI is confirmed, to prevent long-term complications including bone loss, cardiovascular disease, and sexual dysfunction 1, 2
• Fertility preservation counseling should be offered urgently if POI is suspected and the patient desires future pregnancy, as oocyte cryopreservation may still be possible 2

Common Pitfalls to Avoid

• Do not rely on AMH alone for diagnosis—normal AMH does not exclude significant ovarian dysfunction, as demonstrated by cases of negligible AMH with successful spontaneous pregnancies and cases of normal AMH with confirmed POI 3, 6, 4
• Do not delay specialist referral while waiting for repeat AMH, as the hormonal evaluation (FSH/estradiol) is more definitive for POI diagnosis 1
• Do not assume PCOS based solely on increased stroma—PCOS requires either ≥20 follicles per ovary or volume ≥10mL plus clinical/biochemical hyperandrogenism 1