An oral dosage form (D1) comprises hormone-containing daily units (H1) and hormone-free daily units (H2). (H1) contains folic acid in a daily amount of not >;200 mu g and (H2) contains folic acid in a daily amount of greater than 200 mu g. An independent claim is also included for a kit comprising (D1). ACTIVITY : Contraceptive. MECHANISM OF ACTION : None given.