A 22-year-old woman presents with secondary amenorrhoea for 8 months. Serum prolactin is 72 ng/mL, TSH is 8.2 mIU/L, and T4 is low. What is the MOST LIKELY mechanism of her hyperprolactinaemia?

• A Prolactinoma of the anterior pituitary
• B OCP-induced persistent prolactin elevation
• C Stress-related dopamine excess suppressing prolactin
• D Elevated TRH stimulating prolactin secretion secondary to primary hypothyroidism ✓

Explanation

In primary hypothyroidism, low thyroid hormones reduce negative feedback, causing increased TRH secretion. TRH stimulates both TSH and prolactin from the anterior pituitary, leading to functional hyperprolactinaemia. Treating hypothyroidism normalises prolactin. A prolactinoma would not explain the hypothyroid biochemistry. OCP does not cause persistent hyperprolactinaemia after cessation.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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