Recent weight gain in an amenorrheic patient should prompt evaluation for which condition?

• A. Hypothyroidism
• B. Hyperprolactinemia
• C. Anorexia nervosa
• D. Cushing syndrome

Answer: (A)

Weight gain with amenorrhea points toward hypothyroidism because a low thyroid state lowers metabolic rate and often disrupts the hypothalamic-pituitary-ovarian axis, leading to reduced GnRH pulsatility and anovulation. In addition, low thyroid hormones raise TRH, which can increase prolactin and further suppress GnRH, contributing to amenorrhea. So testing thyroid function with TSH and free T4 is the most appropriate first step.

Hyperprolactinemia can cause amenorrhea but typically presents with galactorrhea and is not characteristically associated with weight gain. Anorexia nervosa usually causes weight loss rather than gain. Cushing syndrome can cause weight gain and amenorrhea, but it often has other features (easy bruising, proximal weakness, glucose intolerance) and is less likely the first consideration when weight gain is the prominent accompanying symptom.