Engaging in borderline sex before the menstrual period is over is not healthy for both partners. Sexual intercourse is prohibited during menstruation, and marginal sexual intercourse should also be prohibited. On the one hand, women’s resistance during menstruation is weaker, the cervical opening is in an open state, bacteria are more likely to enter the retrograde infection from the endometrial trauma, which can easily lead to inflammatory infections, endometritis, pelvic inflammatory disease, adnexitis and other diseases, and may even lead to women’s infertility; on the other hand, the menstrual blood enters the male urethra from the male urethral opening, which may also lead to the occurrence of urinary tract infections, prostatitis and other diseases in males.