Most women have some mild pain with their periods. However, if the pain is severe and lasts for several days, then it may be a symptom of a medical condition called endometriosis.

During a woman’s menstrual cycle, the uterus will shed its lining called the endometrium. Sometimes, this tissue, normally found inside the uterus, will grow in other parts of the body, such as the ovaries, the fallopian tubes, and other internal areas. Even when the tissue grows outside the uterus, it still responds to a woman’s monthly hormonal changes. The tissue builds up and breaks down but it has no way to leave the body. This can result in painful inflammation, small cysts, bleeding, and scarring.

Endometriosis is estimated to affect 6% to 10% of women of reproductive age. It is often diagnosed in women in their 30s and 40s, however it can also occur during adolescence. Endometriosis is one of the more common causes of infertility in women.

Common signs and symptoms of endometriosis may include the following:

• Painful periods that may begin before you expect your period and continue for several days
• Pain during or after sex
• Difficulty becoming pregnant
• Irregular periods
• Heavy bleeding during periods and bleeding between periods
• Painful bowel movements during periods

Some women may have no symptoms at all.

If your periods are painful or irregular, or if you are having a hard time getting pregnant, you should talk to your healthcare provider. In some cases, these symptoms may indicate a more serious medical condition.

The cause of endometriosis is unknown. There are theories that genetics may be a factor.

Your healthcare provider may perform several tests to rule out other potential causes of your symptoms such as ovarian cysts and fibroids. These tests may include the following:

• Medical history evaluation
• Pelvic exam
• Laboratory tests to rule out pregnancy
• Ultrasound. During an ultrasound, high-frequency sound waves create an image of internal organs such as the uterus and ovaries
• Computed tomography (CT scan). This imaging test combines a series of x-rays to create detailed images of your organs, bones, and muscles.
• Magnetic resonance imaging (MRI). This imaging test provides a two-dimensional view of internal organs and tissue.
• Biopsy. During this test, a small tissue sample is surgically removed during a procedure called laparoscopy.

Endometriosis is often a chronic disease that may require long-term management. Treatment for endometriosis depends on the severity of the condition and whether you want to have children.

Treatment options for endometriosis may include:

• Over-the-counter pain relievers
• Oral contraceptive pills
• Reproductive assistance if trying to achieve pregnancy
• Laparoscopic surgery to remove endometrium tissue
• In severe cases, surgical removal of the uterus called a hysterectomy

You can’t prevent endometriosis. There is research that suggests you can lower your chances of developing endometriosis with oral contraceptives, and daily exercise.