A 16-year-old adolescent female presents to the hospital complaining of very heavy menstrual bleeding for the last six months. She stated that her cycles are regular, occurring every 29 days, but they last for ten days, and she has to change 10-12 pads per day. Her last period ended a week ago, and she now complains of dizziness when she stands up. She denied concurrent vaginal discharge or abdominal pain. Her past medical and family histories are negative for bleeding problems. Her menarche was at 12 years of age, and she started having regular menstrual cycles at 14 years of age.

She denied all forms of sexual activity. Her examination was significant for mild resting tachycardia and orthostatic hypotension. Her nail beds and conjunctiva were pale. A urine pregnancy test was negative, and her hemoglobin was 10 g/dL. What is the most likely diagnosis for this teenager? *This case is…