MSFinals-1684

A 23-year-old woman student presents to her general practitioner (GP) with menstrual irregularity. Her last menstrual period was 5 months ago. On examination, the GP notes an increased body mass index (BMI) and coarse dark hair over her stomach. There are no other relevant findings. The GP makes a referral to a gynaecologist.
What is the most probable reason for this patient’s menstrual irregularity?