Endometriosis is a women’s medical condition that occurs when the lining of the uterus, called the endometrium, grows in other places, such as the fallopian tubes, ovaries or along the pelvis. When that lining breaks down, like the regular lining in the uterus that produces the menstruation, it has nowhere to go. This causes cysts, heavy periods, severe cramps and even infertility. More than 5 million women in the United States are affected by this condition, according to the National Institute of Child Health and Human Development.