The term “physiological period” generally refers to a woman’s menstruation. It is not recommended to have intercourse during the menstrual period, so as not to cause inflammation of the reproductive organs, menstrual disorders, endometriosis and so on. 1. Inflammation of the reproductive organs: During menstruation, due to the expansion of the vagina and cervix, the endothelial lining can not be repaired in time, the vagina is congested with blood, and the nutritive effect of the blood, if you have intercourse during menstruation, it will increase the chances of bacterial infections, and it will also make the blood flow backward, which will increase the risk of infections, and cause a series of inflammatory diseases of the female reproductive organs, such as vaginitis, endometritis, and pelvic inflammatory disease. 2. Irregular menstruation: women’s menstruation due to its special physiological response, the pituitary ovarian reproductive axis regulation, will trigger the heart and breasts and other parts of the discomfort symptoms, menstruation coitus will be due to emotional excitement lead to endocrine hormone disorders, resulting in menstrual irregularities. 3. Endometriosis: coitus during menstruation will cause the uterus to contract, which may cause the endometrium to squeeze into the pelvis, causing endometriosis, secondary cause dysmenorrhea or infertility. Therefore, it is not recommended to have intercourse during menstruation, pay attention to menstrual hygiene care, change underwear and sanitary napkins, pay attention to abdominal warmth, and be in a good mood.