A 23-year-old nulliparous woman presents with amenorrhea associated with a weight gain of 12 kg, over a period of 6 months. She attained menarche at age 11, and her menstrual cycles have been irregular since then. She is sexually active and uses barrier methods for contraception. Her family history is significant for type 2 diabetes mellitus in both parents. A urine hCG test is found to be negative.