David F Archer et al.
Obstetrics and gynecology, 122(3), 601-607 (2013-08-08)
To assess the efficacy, safety, and tolerability of an extended-duration, combined hormonal oral contraceptive pill (OCP) that reduces the estrogen exposure by almost half compared with other OCPs. This open-label, uncontrolled, multicenter study used an ultra low-dose OCP (1.0 mg