Medical Guide | Women's Health

Endometriosis is an unusual and often misunderstood condition that usually only comes to light when a woman is investigated for infertility.

The endometrium lines the womb and undergoes changes every month. In the month the endometrium grows in readiness to provide a place for a fertilized egg to start to grow. If a woman does not become pregnant the lining of the women is shed - the period.

In endometriosis, the cells that form the endometrium can be found in other parts of the body but most commonly in the pelvis or abdomen. These cells grow to form the bed ready for the fertilized egg, if the pregnancy does not occur they bleed just like the proper lining of the womb. However, the blood and cells have nowhere to go so form pockets of old blood and dead cells. If you look at these pockets they appear like little collections of chocolate, being deep brown. This process is very painful as the forming of the pockets stretches the surrounding tissue, causing the pain and inflammation. Endometrial pockets can be found anywhere in the pelvis and abdomen. They can be found in the ovary itself and form what are known as 'chocolate cysts'.

The cause is unknown.

Of the theories, the most widely accepted is retrograde menstruation. According to this theory some of the menstrual blood produced at period time flows backwards down the fallopian tubes and into the pelvis. Some of the endometrial cells, contained in the menstrual fluid, drop onto the reproductive organs or other areas in the pelvis. These cells cause endometriosis.

What is not known is why these endometrial cells cause endometriosis in some women and not in others.

• you experience unusual pain during your period
• you have exceptionally heavy or irregular periods
• bowel movements and passing urine becomes very painful