Kayla Itsines has spoken candidly about her battle with endometriosis, a disease she has lived with most of her adult life.
The 30-year-old said she knew nothing about endometriosis when she was diagnosed with the condition at 18.
And she is now pushing for more women to feel comfortable talking about it.
"Chances are, if you don't have it yourself, you will know someone that does. We can all do our part to educate ourselves, and create conversations about women's issues WITHOUT shame," she said in a blog post in collaboration with Endometriosis Australia.
"Endometriosis is a condition where tissue, similar to the tissue lining of your uterus, is found on other organs, like your ovaries, which then causes pain and complications."
"Having heavy, painful periods was one of my biggest symptoms and I remember being so jealous of all of my friends who could carry on as normal during their period because that just wasn't the case for me. I used to walk around school with heat pads on my stomach because I was in so much pain. Your period shouldn't be debilitating!"
Itsines also experienced pain in her legs, describing it as a "constant burn or ache" whenever she walked up or down the stairs.
"I always say I have a weak bladder, but I know that's really due to my endo too."
"I also started getting cysts that would burst. I've had cysts burst mid-workout before and that really sucks. Not everyone gets cysts, but this is what ultimately encouraged me to reach out to my doctor."
Kayla said she knew almost nothing about endometriosis when she was diagnosed with it all those years ago.
"So after going through the recommended surgeries and learning to live with the disease today, this collaboration is really close to my heart."
In a previous Instagram post, the Adelaide fitness guru who is the co-founder of the Sweat app, said endometriosis can take a long time to get diagnosed for lots of women as it's "sadly" brushed off as "just your time of the month".
"This is the reason I'm talking to you all about my experience and to try and encourage you to take action if you have very painful periods. One in nine of us have it so you aren't abnormal or a special case and you won't be alone if you do get diagnosed like I did."
Itsines said she didn't know if what she was feeling during her periods each month was "abnormal".
"It took me years of living with that pain before deciding it wasn't right and going to see a doctor to get the surgical treatment I needed and a confirmed diagnosis."
In February last year, the mother-of-one underwent more surgery after suffering the "worst pain" she's ever felt.
Since then, she said some days have been "really tough" especially when you have an energetic toddler.
"But I'm so grateful to have my family close by to help me."
Itsines has continued to share her experience with endometriosis to help "remove the social stigma and increase awareness".
"While I like to keep a lot of my home life private, I realised I could use my social media platform to help others with endometriosis feel less alone," she told Cosmopolitan in March last year.
"I knew that reading someone else's endometriosis story would have made me feel so much better back when I first received my diagnosis."
In 2018, three years after sharing her first Instagram post about her battle with the disease, Itsines said she was "over the moon" to discover she was pregnant with her first child, Arna.
"I really couldn't believe it, and I remember feeling the most enormous sense of gratitude to my body for supporting me – despite my endometriosis struggles – and giving me the opportunity to become a mother. After shouldering the earlier speculation about my fertility, I was so relieved and thankful," she told the magazine.
More than 120,000 women and girls in New Zealand suffer from endometriosis.
The disease often starts in teenage years, according to Endometriosis Australia.
"While endometriosis most often affects the reproductive organs, it is frequently found in the bowel and bladder and has been found in muscle, joints, the lungs and the brain," it states on its website.
March marks Endometriosis Awareness month. For more information about the disease, visit Endometriosis New Zealand.