Endometriosis (en-doh-mee-tree-OH-sis) happens when tissue that normally lines the uterus (the endometrium) grows outside of it. The growths cause pain and other symptoms. Treatment with hormone medicine (for example, the birth control pill) and medicines to ease pain and inflammation can help. Sometimes surgery is needed.

Follow your health care provider's recommendations about having your child:

• Take any hormone medicines.
• Take a nonsteroidal anti-inflammatory drug (NSAID) for pain, such as ibuprofen (Advil^®, Motrin^®, or a store brand) or naproxen sodium (Aleve^®, Naprosyn^®, or a store brand). If the pain usually happens during periods, your child can start taking an NSAID the day before it's expected to come.
• Keep a diary of when pain happens, what medicines they take, and what helps ease the pain.
• See any other providers (for example, one who specializes in treating endometriosis, a massage therapist to help with pain, or a counselor to help with the stress of an ongoing health issue).
• Follow up to check if the treatment is helping.

Other things your child can try to ease pain:

• Heat — Put a heating pad or heat patch on the lower belly or take a warm bath.
• Exercise — Exercising may help ease pain.
• Massage — Massaging the belly and lower back may decrease pain.
• Meditation and mindful movement, like yoga or tai chi — These can help your child relax and may ease pain.

Your child:

• has worsening pain
• gets new symptoms, such as problems peeing or pooping
• can't go to school or work or do other activities (like sports) because of pain
• seems very anxious or sad

Your child is taking hormone medicines and has lower leg pain, chest pain, trouble breathing, weakness, tingling, trouble speaking, or vision problems. These can be signs of a blood clot, which is an extremely rare side effect that can happen from hormone medicines.

What happens in endometriosis? In endometriosis, the uterine tissue grows outside of the uterus — most often on the ovaries, fallopian tubes, outside surface of the uterus, bladder, or ligaments that support the uterus. This tissue swells and bleeds during a period and the blood gets trapped. This irritates the surrounding areas, causing pain. Over time, scars can form.

What causes endometriosis? Doctors don't know why some people get endometriosis. It can run in families.

What are the symptoms of endometriosis? Endometriosis doesn't always cause symptoms. When it does, they may include:

• lower belly or back pain
• heavy periods with large clots 
• pain when peeing
• bowel problems like diarrhea, constipation, and pain or blood when going to the bathroom
• pain with sex
• trouble getting pregnant