Great aunt is also known as menstruation, the difference between withdrawal bleeding and menstruation is the different causes of bleeding, different effects on the body and so on. Withdrawal bleeding is an adverse reaction caused by drugs, such as large doses of progesterone, taking birth control pills, after stopping the drugs, the endometrial lining of the uterus will shed after losing the support of hormones, resulting in vaginal bleeding, which usually occurs 3-7 days after stopping the medication, and it is not uterine bleeding caused by a normal menstrual cycle. Menstruation is a natural phenomenon, each woman has her own menstrual cycle, usually around 28-30 days to come once, is the body’s self-regulation of hormones after the endometrium occurs after the cycle of stripping caused by vaginal bleeding. Retreating bleeding is caused by drugs, which may cause endocrine disorders, and then there is the manifestation of menstrual cycle disorders. Menstruation is a natural phenomenon and will not be harmful to women’s body. In addition, women should observe the symptoms of the body and seek medical advice in time if there are abnormalities.