This is a phase 2, multicenter, double-blind (sponsor-unblinded), randomized, placebo-controlled study to assess the safety and efficacy of elagolix in women with PCOS. PCOS is one of the most common hormonal disorders in women of reproductive age, yet few treatment options are available. This study will help determine if elagolix can impact disordered hormonal dynamics in women with PCOS and at what dosage.