Oral contraceptives are known also as the Pill, OCs, BCs, BC tablets, or birth control pills. This medicine usually contains two types of hormones, estrogens and progestins and, when taken properly, prevents pregnancy. It works by stopping a woman's egg from fully developing each month. The egg can no longer accept a sperm and fertilization is prevented. Although oral contraceptives have other effects that help prevent a pregnancy from occurring, this is the main action. consult gynecologist for further advice..