Reproductive · Year 2 · from Reproductive
Case 1: Anovulatory Bleeding (Dysfunctional Uterine Bleeding)
Clinical Image
Source: Wikipedia - Menstrual cycle - CC BY-SA 4.0
Case Presentation
A 17-year-old female presents with irregular, heavy menstrual bleeding for the past year. Since menarche at age 12, her periods have been unpredictable, occurring anywhere from every 2 weeks to every 3 months. When she does bleed, it is often heavy (soaking through a pad every 1-2 hours for 3-4 days) and prolonged (lasting 10-14 days). She denies sexual activity, hirsutism, or galactorrhea. Physical examination reveals a healthy-appearing adolescent with BMI 24. There is no hirsutism, acne, or acanthosis nigricans. Pelvic examination is deferred given her age and lack of sexual activity. Laboratory studies show hemoglobin 10.2 g/dL (mild anemia), TSH normal, prolactin normal, and pregnancy test negative. Given her age and body habitus, PCOS workup is low yield at this time. Transvaginal ultrasound is not performed given her virginal status. The diagnosis is anovulatory uterine bleeding, common in adolescents due to hypothalamic-pituitary-ovarian axis immaturity. Treatment is initiated with combined oral contraceptives to regulate her cycles and reduce bleeding. Iron supplementation is prescribed for her anemia. She is counseled that many adolescents develop regular ovulatory cycles within a few years of menarche, but if symptoms persist, evaluation for PCOS would be warranted.
Key Learning Points
- Anovulatory cycles are common in the first 2-3 years after menarche due to HPO axis immaturity; without ovulation, no corpus luteum forms, and no progesterone is produced
- Unopposed estrogen stimulates endometrial proliferation; when estrogen levels fluctuate, the endometrium sheds unpredictably, causing irregular and often heavy bleeding
- Combined oral contraceptives provide cycle control by suppressing the HPO axis and providing regular hormone withdrawal bleeding
- If anovulation persists beyond adolescence, PCOS should be considered as the most common cause in reproductive-age women