Endometriosis is a condition caused by endometrial tissue growing outside of your uterus, usually in other areas inside your belly.

Often the tissue grows on or around your ovaries, uterus, and fallopian tubes.

Any endometrial tissue that's in the wrong place acts just like endometrial tissue inside your uterus. It grows and bleeds every month with your period, which can be painful and can cause scar tissue to grow. The scar tissue sometimes blocks your fallopian tubes, which makes it harder to get pregnant.

The exact cause of endometriosis isn't clear.

With endometriosis, a few small pieces of the endometrial tissue that should leave your body with your period blood could instead travel up the fallopian tubes. One of those small pieces could even get stuck inside your belly and start to grow.

Endometriosis sometimes runs in families.

Pain is the most common symptom.

Different women may have different types of pain:

During pregnancy, symptoms may stop for a while or sometimes forever. Symptoms often stop after menopause.

Doctors may suspect endometriosis if you have belly pain that seems to come and go with your period or when you have sex or if you have difficulty becoming pregnant.

To see for sure whether you have endometriosis, the doctor may look inside your belly using a flexible viewing tube. During this procedure, you will have anesthesia and then your doctor will insert the viewing scope through a small cut near your belly button.

Treatment depends on your symptoms, pregnancy plans, age, and the stage of endometriosis.

Doctors treat endometriosis with nonsteroidal anti-inflammatory drugs (NSAIDs) to help with pain, medicines that contain hormones (such as birth control pills), or surgery using a laparoscope to remove or destroy the misplaced endometrial tissue.