Single eyelids look small and many people don’t like it. Double eyelids and big eyes make the eyes more attractive and can show more temperament between a blink and a close. We all know that you can’t do double eyelids during menstruation, what is the reason for this? There are fibrin and fibrinogen precursor activators in human blood that have a coagulation effect and a hemolytic effect. In women, the precursor activator can cause cyclic bleeding in the uterus during menstruation because it is greatly increased in the blood and in the uterus. Under normal circumstances, the wound after cosmetic surgery should form a clot soon, but women can destroy the clot in the wound after cosmetic surgery due to the increase of precursor activators of fibrinogen in the blood that reaches its maximum value during menstruation, and cause bleeding or prolonged bleeding, thus causing wound infection in case of germs taking advantage of the invasion. In order to prevent wound infection after eyelid surgery, experts recommend that women should have cosmetic surgery only three days after the cessation of menstruation.