system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 15-year-old girl comes to the physician because of a 2-year history of irregular menstrual bleeding. Menses have occurred at irregular 45- to 60-day intervals since menarche at the age of 13 years. Her last menstrual period was 5 weeks ago and lasted for 7 days with heavy flow and no cramping. She is not sexually active. She is 171 cm (5 ft 7 in) tall and weighs 58 kg (128 lb); BMI is 20 kg/m2. Her temperature is 36.6°C (97.8°F), pulse is 80/min, and blood pressure is 110/60 mm Hg. Pelvic examination shows a normal-appearing vagina and cervix. Bimanual examination shows a normal-sized uterus and no palpable adnexal masses. The remainder of the physical examination shows no abnormalities. A urine pregnancy test is negative. Which of the following is the most likely explanation for this patient's symptoms?
assistant
Anovulation