A 28-year-old woman presents with primary amenorrhea, absent secondary sexual characteristics, and elevated FSH (68 IU/L). Karyotype is 46,XX. The MOST appropriate next investigation to determine the cause is:

• A GnRH stimulation test to assess pituitary responsiveness
• B Prolactin and thyroid function tests
• C MRI pituitary to exclude craniopharyngioma
• D Pelvic ultrasound and anti-Müllerian hormone (AMH) level to assess ovarian reserve ✓

Explanation

Elevated FSH with absent secondary sexual characteristics indicates hypergonadotropic hypogonadism (primary ovarian insufficiency/POI). The priority investigation is pelvic ultrasound to assess uterine and ovarian morphology, and AMH to quantify ovarian reserve. In 46,XX POI, ultrasonography may show streak ovaries (Turner's phenotype variants) or small follicle-depleted ovaries. GnRH stimulation test is useful in hypogonadotropic hypogonadism (low FSH). Prolactin/TSH and pituitary MRI are indicated in secondary amenorrhea with low/normal FSH, not hypergonadotropic primary amenorrhea.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.