Normally, endometrial tissue is found only inside the uterus. The uterus is the reproductive organ where a fetus develops. Hormones cause the tissue to form there, preparing the body for a fertilized egg. If you do not become pregnant, the tissue leaves the body during menstruation.
In endometriosis, endometrial-like tissue is found outside the uterus. For example, it may be found on organs in the abdomen or pelvis. In these places, the tissue still responds to hormones. It swells, breaks down, and bleeds. But it is unable to leave when you menstruate. Surrounding tissue becomes inflamed. There is often scarring.
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Possible causes include:
- Menstrual tissue backs up through the fallopian tubes and spills into the abdomen
- Immune system may allow the tissue to implant on other organ surfaces and develop into endometriosis
- Lymph system may carry endometrial cells from the uterus
- Certain cells left behind on abdominal organs during embryonic development can turn into endometrial tissue
Hormones and growth factors cause the disease to progress.
Last reviewedAugust 2014by Andrea Chisholm, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.