Sexual intercourse is generally not recommended during endothelial transformation. During the period of endometrial transformation, usually during menstruation, menstruation is generally not recommended to have sex. Because the cervical opening is open at this time, coitus at this time is easy to lead to bacterial invasion, easy to cause vaginitis, cervicitis, etc., if the inflammation is not well controlled, it is also easy to cause uterine cavity infection. At the same time, coitus during menstruation, but also easy to cause capillary rupture increased, easy to trigger increased menstrual flow, abdominal pain and other symptoms. Sex during menstruation is not only hazardous to women’s health, but may also have an impact on men’s reproductive health. Men’s genitals are also susceptible to infection by menstrual blood during sexual intercourse, and urethral irritation occurs. Therefore, coitus should be avoided during the period of endometrial transformation.