Backflow of menstrual fluid through the fallopian tubes into the peritoneal cavity.
A phenomenon in which menstrual blood deviates from its usual course and enters the body cavity instead of being discharged through the uterus.
A small amount of menstrual fluid flows backwards from the uterus into the fallopian tubes rather than exiting through the vagina. This backward flow, known as retrograde menstruation, is believed to be a potential cause of endometriosis.