Sports Illustrated Swimsuit model Olivia Culpo is opening up about her painful health battle, which she has kept secret until now.

She shared on Instagram Story: “I've never publicly said this before but I have endometriosis. Aka the most excruciatingly painful cramps/periods. Anyone else reading this have Endo? No fun.”

Endometriosis is a condition that causes the tissue that normally grows inside the uterus to grow outside of it on the ovaries, Fallopian tubes or intestines, causing physical pain and issues with menstruation.

She shared her sympathy with fans going through the same thing, writing: “I can't believe that a lot of you also suffer from endometriosis. It is so not fun, very painful.”

While surgery is possible, she isn’t going that route right now. The 28-year-old adds that people with painful periods need to consider the implications for fertility: “The thing I'm gonna say about endometriosis that I just think is really important is if you are having very painful periods and you are not being diagnosed with what you think could be endometriosis, definitely do your research because if you don't discover that you have this, it could get in the way of your fertility. You could have tissue growing in areas that you really shouldn't have that would interfere with maybe getting pregnant some day, your eggs could be getting damaged.”

Culpo continued, adding that she’s heard about a lot of women who have suffered through infertility: “The reason why I'm so passionate about talking about this is because my doctor tells me about people who come to her in their 30s, 40s, 50s, 60s about not having been able to have kids. The thing that's so sad about that is because they may have had endometriosis that may have affected their fertility in some way and if they had caught it earlier, they could have frozen their eggs. There would have been more options.”