It is normal to have a physiological reaction during menstruation, which usually does not change the amount of menstrual flow; however, it is possible that having sex or masturbating may lead to an increase in the amount of menstrual blood. Having sex or masturbating while menstruating may result in localized congestion and increased blood flow, which, combined with uterine contractions during orgasm, may lead to an instant increase in menstrual flow. Having intercourse or masturbating during menstruation may not only cause an increase in menstrual blood flow, but will also increase a woman’s risk of developing gynecological infections. This is due to the fact that during menstruation the cervical opening is open and the uterine lining is invasive, making it highly susceptible to infection. Therefore, it is not recommended to masturbate or have sex during menstruation.