Endometriosis is a painful disorder of the female reproductive system. It is a condition in which bits of the tissue similar to the lining of the Uterus (endometrium) grow in other parts of the body.
When you menstruate, the endometrial lining, also called endometrial tissue is discharged out of your body along with the menstrual flow. If you have endometriosis, the tissue from the lining of the Uterus also gets lodged outside your uterus, in other parts such as the fallopian tubes, ovaries, or your Pelvis.
