It is more appropriate to have intercourse 3 days after menstruation, as there are still broken blood vessels and glandular ducts on the surface of the uterine cavity just after menstruation, and tiny blood vessels still have the phenomenon of blood leakage. The uterus still needs a few days to recover after the endometrium is shed. The main effects of premature intercourse on women’s health are: 1. Infection is easily brought about because the endometrial surface has not yet completely healed, and sex at this time will bring bacteria and increase the chance of infection in the uterine cavity. 2. Abnormal bleeding is easily caused because sexual excitement during sex leads to increased uterine spasms and uterine congestion, and the incompletely healed endometrium and fractured blood vessels will be too contracted and lead to bleeding and the phenomenon of menstrual return. 3, may lead to menstrual irregularities, premature intercourse as with menstruation and affect the menstrual cycle, resulting in prolonged periods, increased menstruation, irregular menstruation.