Taking birth control pills may lead to early menstruation, which is usually determined by the time of taking the pill. Contraceptives are categorized into emergency contraceptives, short-acting contraceptives and long-acting contraceptives. Emergency contraceptives contain relatively high levels of hormones, which can lead to hormonal disorders in the body, resulting in menstrual abnormalities, leading to early or delayed onset of menstruation. If you are taking short-acting or long-acting contraceptive pills, missed doses can also cause menstrual disorders. Contraceptive pills can not only achieve the function of contraception, but also have a certain therapeutic effect on gynecological diseases, common irregular menstruation, polycystic ovary syndrome and so on. However, all drugs have a certain effect, so you need to strictly follow the doctor’s instructions when taking drugs.