SUN-442 The right glucocorticoid dose for CAH to promote pregnancy

Abstract Disclosure: S.D. Graybill: None. Introduction: Dosing for glucocorticoids in congenital adrenal hyperplasia (CAH) can be challenging, especially when trying to balance potential fertility benefits. Both overdosing and underdoing glucocorticoids can cause menstrual irregularities in women with CAH. Case: 42-year-old woman with classic CAH diagnosed in infancy presented for amenorrhea for 19 months, mild hirsutism, and weight gain. She was taking hydrocortisone 15 mg AM, hydrocortisone 5 mg PM, and fludrocortisone 0.1 mg daily. She had never been pregnant but desired pregnancy if it did not require assisted reproductive technology. Her body surface area indicated that hydrocortisone 14 mg daily should avoid problems from adrenal insufficiency so we lowered hydrocortisone to 10 mg AM and continued 5 mg PM. Six months later, she has lost some weight but her menstrual cycles had not resumed. Furthermore, 17-hydroxyprogesterone increased from 6090 ng/dL to 12,500 ng/dL and androstenedione increased from 345 ng/dL to 669 ng/dL. It seemed likely that adrenal-derived progesterone was causing her amenorrhea so we added a long-acting glucocorticoid at bedtime to blunt the overnight ACTH rise. After 2 months with the addition of methylprednisolone 2 mg at bedtime, menstruation resumed and androgen levels normalized. However, she developed urinary incontinence at night and cramping so she stopped the afternoon dose of hydrocortisone. Three months later, her menstruation become regular every month on hydrocortisone 10 mg AM, methylprednisolone 2 mg QHS, and fludrocortisone 0.1 mg daily. Conclusion: This case highlights the benefit of bedtime dosing of long-acting glucocorticoids for CAH because they can lower excess androgen levels, improving fertility. Presentation: Sunday, July 13, 2025