Women are usually allowed to have anal sex during their periods, also known as “going in the back door”, but it is not recommended to have this unhealthy form of intercourse, nor is it recommended to have it at this time. Although anal sex does not affect a woman’s menstruation and will not cause pregnancy, anal sex can easily lead to anal injuries. Because the anus does not secrete fluid for lubrication, it is likely that the skin in the anus will be bruised and infected during the friction process after penile penetration. There is also the possibility of serious consequences of anal fissures. In addition, the proximity of the anus to the vaginal opening can bring bacteria into the vagina leading to gynecological infections. In summary, it is not recommended to have anal sex during menstruation, and if you want to have anal sex beforehand you must pay attention to good lubrication work.