According to some scholars of sex, sexual intercourse was done during menstruation can be done. However, from the medical side, having sex while menstruating until now was thought to be one of the factors causing the emergence of several conditions, such as endometriosis and infection.
Endometriosis is the growth of cells on the uterine wall (endometrium) or elsewhere outside the uterine wall. When this happens, then the person will feel pain during menstruation (dysmenorrhea).
Many factors that cause this endometriosis. One of them is regurgitation or back flow of menstrual blood from the uterus to the ovaries channel and into the abdominal wall. This backflow can occur from sexual intercourse during menstruation.
In addition, infection can also occur, both in women and men. In women, infection usually occurs due to changes in the acidity of the vagina during menstruation. Consequently, vaginal secretions ability to fight bacteria that enter through the change.