This patient with polycystic ovary syndrome (PCOS) with heavy menstrual bleeding and hirsutism should be treated with combined estrogen-progestin oral contraceptive pills. Patients with PCOS remain in a stagnant follicular stage resulting in unopposed estradiol secretion from small ovarian follicles, causing proliferation of the endometrium in the absence of progesterone secretion from a corpus luteum. This predisposes patients to endometrial hyperplasia and heavy menstrual bleeding as a result of anovulatory bleeding. Intraovarian androgen production is also increased in PCOS, resulting in the hyperandrogenism and hirsutism associated with the disorder. Estrogen-progestin oral contraceptive pills are first-line therapy for the menstrual irregularities and hirsutism associated with PCOS. This therapy prevents unopposed estrogen-induced proliferation of the endometrium and suppresses the excess androgen production associated with PCOS. This would be appropriate therapy to treat both issues in this patient, who does not currently desire fertility.

Progestin therapy alone, either through periodic progestin withdrawal or use of a progesterone-eluting intrauterine device, will provide endometrial protection and treat this patient's menstrual irregularity. However, progestin therapy alone does not suppress androgen production and would not treat this patient's hirsutism.

Metformin has several favorable metabolic effects in patients with PCOS, including increased insulin sensitivity and reduced serum free testosterone. However, it has been shown to be less effective than oral contraceptives for improving the menstrual pattern and reducing serum androgens. It also does not provide endometrial protection and is considered a second-line therapy for patients with PCOS with significant menstrual irregularities and hirsutism who are unable to tolerate oral contraceptive pills.