A woman can have her blood tested when she has her period. The amount of blood drawn for the test is about 8-10 ml, which will not affect the body, and the sex hormone six test can be performed on the third day of menstruation to check the ovarian secretion of the woman. The results of coagulation, routine blood tests or liver and kidney function tests are subject to certain errors, and hormone levels change drastically during menstruation, resulting in deviations in some indicators. In case of emergency during menstruation, blood tests should be taken to check for emergencies and to avoid delaying the best treatment time for the disease.