Lena Dunham isn't shy about sharing the ups and downs of living with endometriosis. People who have heard of the disorder—and that's still not many—usually think it just causes women to have painful periods. Dunham's recent Snapchat challenges that stereotype as she shows the world her scars from endometriosis-related surgeries:

Here's what everyone should know about the disorder: It causes the tissue lining the uterus (which usually gets flushed out during menstruation) to grow where it shouldn't be—on the ovaries, fallopian tubes, or intestines. Symptoms include terrible cramps, long and heavy periods, pain during sex, or even infertility. Sometimes surgery is required to properly diagnose endometriosis and remove the excess tissue to ease the pain.

The crazy thing is one in ten women in the U.S. deal with endometriosis at some point in their lives, making it even more important that Dunham is sharing her story to raise awareness of the common disorder.

READ THIS NEXT: Kristen Bells Mocks the Gender Pay Gap in This Funny (but Sadly True) Video Overshare Promo