A 15-year-old girl with a BMI of 15 kg/m² presents with secondary amenorrhea for 6 months. She reports restrictive eating and excessive exercise. Laboratory evaluation shows low LH (0.5 IU/L), low FSH (1.2 IU/L), and low estradiol (<20 pg/mL). Which of the following is the underlying mechanism of her amenorrhea?

• A Premature ovarian failure with elevated gonadotropins
• B Functional suppression of the hypothalamic-pituitary-ovarian axis ✓
• C Androgen excess from adrenal hyperplasia
• D Hyperprolactinemia from pituitary microadenoma

Explanation

Functional hypothalamic amenorrhea results from suppression of GnRH pulsatility due to energy deficit from low weight, excessive exercise, or stress. This leads to low LH, FSH, and estradiol levels. Premature ovarian failure would show elevated FSH (>40 IU/L). Adrenal hyperplasia would present with elevated androgens and virilization. Hyperprolactinemia would show elevated prolactin levels and is not suggested by this clinical picture.

Reference: Williams Gynecology, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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