There is no evidence that tetanus shots affect menstruation. Tetanus shot refers to tetanus vaccination. The main ingredients of tetanus shot are tetanus antitoxin and tetanus immunoglobulin, etc. The main effect is to prevent tetanus caused by tetanus bacillus. In order to avoid allergic reactions, skin tests will be conducted on the inoculants before the tetanus shot is administered, and the inoculation will only be allowed if the skin test reaction shows normal. Menstruation, on the other hand, is a physiological manifestation of women. Menstruation is formed when the uterine endometrium under the stimulation of sex hormones undergoes cyclic thickening and shedding. It can be seen that when there are changes in menstruation, such as changes in menstrual flow, menstrual cycle and other factors, they are caused by direct or indirect effects on the endometrium. Judging from the composition and mechanism of action of tetanus shot, there is no possibility of affecting the uterine lining, therefore tetanus shot has no effect on menstruation.