Retrograde menstruation.
In retrograde menstruation, menstrual blood containing endometrial cells flows back through the fallopian tubes and into the pelvic cavity instead of out of the body.
What does retrograde menstrual flow mean?
Retrograde menstruation is when a woman's menstrual flow moves in the wrong direction. Most women experience this to some extent, but if it's severe, it can cause pain and may lead to endometriosis.
How does retrograde menstruation occur?
Retrograde menstruation occurs when menstrual blood and uterine tissue enters the peritoneal cavity by flowing through the fallopian tubes. The possible relationship between this phenomenon and endometriosis was first described by Dr. John Sampson in the 1920s, and this theory prevailed for decades.
