According to Endometriosis Australia, endometriosis is a chronic condition that affects a woman's reproductive organs. It happens when the cells in the lining of the uterus (called the endometrium) grow outside of it.
It is a condition that also affects one in 10 women across the world, but is often left undiagnosed or misdiagnosed.
This is why the admissions of these endometriosis-suffering celebrities are so important; each woman is sharing her story in a bid to raise awareness about a subject that's not talked about enough.
This is what we've learnt...
It can often be misdiagnosed
Pop singer Halsey is proof that even if you do seek medical attention, sometimes, endometriosis can go undiagnosed.
"I was recently diagnosed after years of suffering and finding myself doubled over backstage in the middle of my sets, or fighting back tears on an airplane, or even being in so much pain I would vomit or faint," the 24-year-old wrote on Twitter in 2016.
"With doctors essentially telling me I was being a big baby about my period, or misdiagnosing polycystic ovarian syndrome (PCOS)… Finding out that I had [endometriosis] was the most bittersweet moment because it meant I wasn't crazy!"
"I wasn't a 'baby'! I had every right to be feeling like the world was caving in. But it was terrifying to find out."
The take-home message? If you're in pain and can't find relief despite seeing a doctor, see as many as it takes until the treatment one gives you makes you start to feel better.
It can impact your fertility
After being diagnosed with both PCOS and endometriosis, Jaime Kingwas faced with the very real possibility that, upon this discovery, she couldn't have children.
However, as the now-mum-of-two told her Instagram followers, after eight years of pain and undiagnosed PCOS and endometriosis, one doctor finally diagnosed her.
"For all the struggling women and moms out there that think they are alone this is the truth about conceiving my son and struggles after," she wrote.
"[My doctor] saved my life from a severe ectopic [pregnancy], five miscarriages, five rounds of IVF, 26 IUIs, most with no outcome and four-and-a-half years of trying to conceive."
Others haven't been quite as lucky as Jaime; years ago, when Dolly Parton was required to undergo a partial hysterectomy following her endometriosis diagnosis, she fell into depression after discovering she could no longer have children.
Ex-radio host Mel Grieg also opened up about her fertility struggles and the pain that accompanied them.
"I went off the pill recently to try for babies," she says. "And now, just like when I was first diagnosed at 17, I feel every ounce of pain my endo brings every month.
"I go into self-lockdown for 24 hours at the start of each cycle; I can't move, every step I take I'm in severe pain. Ironically the pain feels what I envisage childbirth to be: absolutely horrific."
In an essay for the Australian Women's Weekly in 2016, Mel opened up about her slim one to five per cent chance of falling pregnant naturally.
"I don't feel that I'm a real woman. I know I shouldn't feel this way, but I do. But that's okay. It doesn't change the way I will love my children if I manage to have them, or how I will be as a mother."
It can influence other parts of your life
Lena Dunham has been very vocal in how her endometriosis diagnosis changed her life (she not only endured physical pain, but was emotionally aggrieved for years by the debilitating condition before she was treated for it).
She has since been treated and now embraces her pain like a badge of body-awareness honour.
"All along the way, a massive fear of mine was 'being discovered,' that someone would decide I wasn't strong enough for my work or my life because of what I dealt with physically and emotionally," she says.
"But I am strong because of what I've dealt with. I am oddly fearless for a wimp with no upper-body strength. And I am no longer scared of my body. In fact, I listen to it when it speaks. I have no choice but to respect what it tells me, to respect the strength of its voice and the truth of my own."
Love Island star Erin Barnett was forced to defend her stomach tattoo which she had done as a result of her endometriosis surgery.
"Everyone asking about my stomach tattoo. I got this tattoo to cover up scars on my stomach as I've had many ovary operations due to having endometriosis & polycystic ovaries," she explained via social media.
"So to everyone calling it a 'tramp tattoo'" she wrote and then posted an emoji that is giving the finger.
It can be treated
Star Wars: The Last Jedi star Daisy Ridley was diagnosed with endometriosis at just 15 years old. And this now-26-year-old is active in encouraging women of all ages to seek medical help if they feel something isn't right.
"To any of you who are suffering with anything," she posted on Instagram.
"Go to a doctor; pay for a specialist; get your hormones tested, get allergy testing; keep on top of how your body is feeling and don't worry about sounding like a hypochondriac."
Julianne Hough has become the face of an awareness campaign called Get in the Know about ME in Endometriosis. The actress and dancer started experiencing symptoms when she was 15 but wasn't diagnosed until years later and has stressed the importance of talking about the condition openly and women being supportive of each other.
"So even if you're not the me in endometriosis, there might be someone around you who might be. It's all about starting this conversation. I want to be a voice and a person who can help women," she said in 2017.
"I don't care about being private about this anymore because I really want the women that are going through debilitating pain to benefit from my story or this campaign."
Endometriosis symptoms checklist
According to Better Health Victoria, the pain endometriosis produces is enough for young girls to have to stay home from school, and women to stay home from work.
Not only that, but research shows that this condition can be inherited and it often goes undiagnosed for up to 10 years because, as women, we normalise the pain by not seeking medical advice.
If you, or someone close to you are experiencing these symptoms collectively, you may have endometriosis. The next step is to make an appointment with your GP to investigate it a littler further.
- Pelvic and ovulation pain
- Nausea and fatigue
- Painful periods, and pain during sex
- Pain in your lowerback and legs
- Bowel and bladder symptoms
- Premenstrual syndrome (or, what is commonly known as PMS)
WATCH video below: 10 scary facts about endometriosis.