If you have intercourse just after menstruation, it may cause inflammation and infection, endometriosis, dysmenorrhea and other adverse effects. 1. Inflammatory infections: Blood is a good petri dish for bacteria, and the process of coitus will carry germs, which are likely to cause bacteria to grow and multiply in the bloodstream, thus causing infections and the formation of vaginitis, endometritis, pelvic inflammatory disease and so on. 2. Endometriosis: coitus during menstruation may result in the backflow of menstrual blood to the pelvis, which in turn causes menstrual blood to be planted in the pelvis, causing the corresponding foci to arise, and gradually forming endometriosis. Then it may cause patients to have dysmenorrhea, painful intercourse, and even infertility and other serious consequences. 3. Dysmenorrhea: intercourse during menstruation can make the pelvis congested, which can easily lead to an increase in the amount of menstruation, prolonged menstruation, and stimulate the uterus to contract and cause dysmenorrhea. Reminder: coitus is not recommended during menstruation, such as coitus after physical discomfort, it is recommended to seek medical attention in a timely manner, improve the relevant examination, under the guidance of a specialist doctor to actively deal with, so as to avoid aggravation of the condition.