More than half of women are affected by endometriosis, a condition in which tissue from the uterus migrates to parts of the pelvic region, resulting in painful cramps and sometimes infertility.
Despite how common the disease is, many women are still uninformed about it and its symptoms, which has prompted celebrities with endometriosis to come forward and be brave spokeswomen for the illness.
"To say that there was a lot of blood would be a massive understatement," she wrote about the painful and heavy periods she experienced. "Because I assume only women are reading, I will be detailed in explaining that I ruined my rug, my linens, bled all over my car and through dozens of pads and tampons. Not to be too graphic, but to hopefully help someone, it was literally clumps of blood."
But aside from the symptoms, the most heartbreaking thing about endometriosis is that it makes it hard for sufferers to have children.
“[After my diagnosis], I was told I would never have children naturally, that I only had a 10 to 15 percent chance of having them in vitro,” Top Chef host Padma Lakshmi said in 2015. “When you’re staring down the barrel of your 40th birthday and you hear that you can’t have kids because this disease went unchecked and undiagnosed for so many years, it’s devastating.”
Not all women with the condition are infertile, though. Padma was able to give birth to a daughter, Krishna, in 2010, which she said was a "gift from God."
Other stars have opened up and talked about their experiences, too. Check out the gallery below to see celebrities you didn't know have endometriosis.