Health Check: are painful periods normal?
Endometriosis is a condition in which tissue similar to the lining the endometrium (womb), grows outside of the womb. It can grow on the ovaries, bowel, and in some rare cases has even been found outside of the pelvis such as the lungs. The hormones that trigger a period cause bleeding at these sites of implanted endometrial tissue, and this causes pain.
Endometriosis usually causes period pain to start earlier and last longer than what is commonly experienced with menstruation. Sometimes the pain doesn’t go away when the period ends. Women with endometriosis can describe pain at the the time of ovulation, or pain with sex.