Relative Desirability of Metformin vs. Birth Control Pill in Treating PCOS in Women of Later Reproductive Age

Inclusion Criteria: * Women with PCOS aged 40-49 years. Subject is considered to have PCOS if she has current or verifiable history of: a) clinical and/or biochemical evidence of hyperandrogenism plus b) oligomenorrhea or irregular menstruation (substantially inconsistent menstrual cycle length). Subjects with fewer than 10 menses/year or average menstrual cycle length \>35 days are allowed to participate if they have a compelling past history of oligomenorrhea (average menstrual cycle length \>45 days or fewer than 9 menses/year) or irregular menstruation. * Screening safety labs within normal reference ranges although mild abnormalities that are common in obesity and/or hyperandrogenism will not be grounds for exclusion (see exclusion criteria). * Subjects must be willing and able to provide written informed consent. * Willingness to strictly avoid pregnancy (using non-hormonal methods) during the time of the study * Willingness and ability to comply with scheduled visits and study procedures Exclusion Criteria: * Postmenopausal status (i.e., absence of periods for previous year plus elevated follicle stimulating hormone \[FSH\] level) * Biochemical evidence for perimenopause as defined by an anti-Mullerian hormone \<0.5 ng/mL. As an alternative, cycle day 3 FSH \> 9 IU/L (with concomitant estradiol level \>80 pg/mL), if this testing is available, will serve as evidence of perimenopause status. NOTE: If FSH \>9 IU/L on screening (but it is not cycle day 3), FSH and estra…