A condition whereby endometrial tissue builds up in parts of the uterus where it does not belong or areas outside of the uterus, forming ‘ectopic implants’. Unlike the normal tissue lining the uterus, ectopic tissue has no place to shed in response to a decline in estrogen and progesterone. This results in debris and blood accumulating at the site of the implant leading to inflammation, scarring and adhesions that ultimately cause symptoms and complications. Symptoms typically occur in a cyclic fashion with menstrual periods, the most common being pelvic pain and cramping before and during periods; pain during intercourse; inability to conceive; fatigue; painful urination during periods; gastrointestinal symptoms such as diarrhea, constipation, and nausea.