A 16-year-old girl presents with irregular heavy menstrual bleeding since menarche 2 years ago. Cycles occur every 45-90 days with prolonged bleeding lasting 10-14 days. Hemoglobin is 9.2 g/dL. Pelvic ultrasound is normal. Which of the following is the most likely underlying cause of her abnormal uterine bleeding?

• A Endometrial polyps
• B Hypothyroidism
• C Coagulation disorder (von Willebrand disease)
• D Anovulation due to immature hypothalamic-pituitary-ovarian axis ✓

Explanation

In the first 2-3 years after menarche, anovulatory cycles are common because the positive feedback mechanism for the LH surge is not yet mature. This leads to irregular, often heavy bleeding from unopposed estrogen stimulation of the endometrium. While von Willebrand disease should be considered in adolescents with severe menorrhagia at menarche, the pattern of irregular cycles over 2 years is more consistent with anovulation. Endometrial polyps are rare in adolescents. Hypothyroidism can cause menorrhagia but would typically present with other systemic features.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.