This is what happens when the uterine lining, otherwise called the endometrium, grows in other places, such as the pelvis, fallopian tubes, and ovaries. It can also be found in the vagina, cervix, bladder, and intestines. During menstruation, when the lining breaks down, these break-away growths have nowhere to go, thus leading to heavy periods, serious cramping, painful sex, cysts, and infertility. Other symptoms include lower back and abdominal pain, diarrhoea, constipation, blood tinged urine, etc.
It typically affects women in their reproductive years, and is one of the leading causes of pelvic pain and reasons for laparoscopic surgery and hysterectomy. Most cases are diagnosed in women aged between ages 25 to 35 years, but it has also been reported in as young as 11 year old girls. However, like uterine fibroids, it is rare in postmenopausal women. It is also more prevalent in Caucasian women, as against women of Afro or Asian origin. It has also been found to be more common with taller, thin women with a low body mass index. Delayed childbirth is also thought to increase the risk. Women with shorter menstrual cycles are also at greater risk. Lastly, genetic factors could also make it more likely for a woman to develop the condition. With respect to fertility, about 20% to 50% of women being treated for infertility have endometriosis.