Birth control pills can cause menstrual disorders. Menstrual disorders generally refer to early or delayed menstruation, increased or decreased bleeding, and longer or shorter periods. Menstruation is related to the level of estrogen and progesterone in the body. Some birth control pills contain progesterone, estrogen or a combination of both hormones, which may lead to menstrual disorders after use. Short-acting contraceptives are estrogen and progestin combination preparations with low hormone content, which have less effect on menstruation and are also used in clinical practice to regulate menstruation, but long-term use can also lead to menstrual disorders; emergency contraceptives and long-acting contraceptives are both highly effective progestins, which tend to interfere with the normal hormones in the body and the state of the endometrium, with relatively large side effects and a high incidence of menstrual disorders. When menstrual disorders occur, occasional low menstrual volume and black color can be treated without special treatment, and most of them can recover on their own after stopping the pill for a period of observation; if the menstrual period is prolonged for more than one month, you need to consider the complication of infection and seek timely medical attention for scraping treatment and biopsy to prevent malignant changes; if the menstrual period is prolonged, consider whether the contraception has failed and suggest to do early pregnancy test to exclude the possibility of pregnancy. When menstrual disorders occur, we should pay attention to whether they are combined with other gynecological diseases, such as endometriosis, uterine fibroids, cervical cancer, etc., which can lead to menstrual disorders, not necessarily caused by contraceptives.