Progestin-only rings are now in development, contain 100mg medroxyprogesterone acetate (MPA), and suppress ovulation (112). These rings are placed on day 5 of the cycle and are removed after 21 days of use in order to provide a withdrawal bleed. Other progestin-only rings included those impregnated with norethindrone; these rings have been associated with irregular bleeding and ovulation (113,114).