A 30-year-old woman presents with a history of no menses since she stopped taking oral contraceptives 6 months ago in order to conceive. She had undergone puberty that was normal in both timing and development, with menarche at 12 years of age. At 18 years of age, she started taking oral contraceptives for irregular menses. She reports stress at work. Her weight is 59 kg, and her height 1.66 m; her body-mass index (the weight in kilograms divided by the square of the height in meters) is 21.3. There is no galactorrhea, hirsutism, or acne. The pelvic examination is normal, a pregnancy test is negative, the prolactin level is normal, and the follicle-stimulating hormone (FSH) level is in the menopausal range. How should she be evaluated and treated?