Retrograde Menstruation

Last Updated: February 7, 2018

Definition - What does Retrograde Menstruation mean?

Retrograde menstruation occurs when menstrual blood containing cells from the uterine lining, called the endometrium, flow backwards into abdomen, as opposed to leaving the body during a menstrual period. Once in the abdomen, the endometrial cells and tissues attach to the surface of the organs, growing and thickening into a layer of blood, which becomes trapped in the pelvic cavity. Retrograde menstruation is considered one of the possible causes of endometriosis, a known cause of infertility.

FertilitySmarts explains Retrograde Menstruation

At the beginning of each menstrual cycle, the female body grows a thick layer of blood and tissue in the uterus. This layer, called the endometrium, is grown in preparation for possible implantation of a fertilized egg. If ovulation occurs and the egg is not fertilized within its 24-hour lifespan, it dies and is passed out of the body. This triggers the uterine lining to shed, causing menstruation. For an average of 3-7 days, the shedding creates a steady flow of menstrual blood or a period. Once the period has ended, a new menstrual cycle begins, and another layer begins to regrow in preparation for another attempt at conception.

When retrograde menstruation occurs, that lining fails to exit the body, and instead floods the fallopian tubes, potentially entering the pelvic cavity. This scatters endometrial tissues and cells (the same responsible for growing the uterine lining) throughout the pelvic area. This is the process thought to cause endometriosis.

Endometriosis refers to the growth of endometrial cells and tissue on organs in the abdomen. The cells are most often found on the ovaries, pelvic lining, and fallopian tubes. Once settled on the organs, the tissues react as they normally would in the uterus, and they grow and thicken into a rich layer of blood. However, instead of being able to shed and exit the body during menstruation, the tissue stuck in the pelvic has nowhere to go. The organs may become irritated, cysts can develop, and organs may stick together as the tissue form thick bands. As a result, endometriosis can cause severe pain during menstruation (dysmenorrhea), and prevent the growth of a healthy endometrial layer. It can also prohibit normal functioning of affected sex organs, including the ovaries and fallopian tube, by causing blockage, inflammation, and irritation. Consequently, these complications of endometriosis can lead to infertility.

There is no singular cause of retrograde menstruation. However, it may be anatomically related; the shape, structure, and configuration of the pelvic organs may play a role in causing the abnormality. Additional risk factors for retrograde menstruation may include:

  • Vaginal or cervical obstructions
  • Age of first menstruation
  • Duration of menstruation
  • Excessive use of alcohol

There is no known cure for retrograde menstruation, but medication to control hormones and endometrial growth and surgery may help alleviate symptoms of endometriosis.

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