Jasmine Yarbrough's sister Jade steps out looking healthier after revealing 'severe' health diagnosis and undergoing extensive surgery for stage 4 endometriosis

Jade Yarbrough is fighting her way back to health and fitness after undergoing surgery for a severe health issue. 

The younger sister of Karl Stefanovic's wife, Jasmine, was spotted on Wednesday looking much better amid her battle with stage 4 endometriosis.

The 31-year-old was feeling well enough to take in a session at the gym, which she attended at a Bondi venue alongside her best mate, model Montana Cox. 

Jade dressed casually for her workout, donning a fitted tank top with matching bike shorts. 

She draped a hoodie over her shoulders, and added a pair of black and white trainers. 

The interior designer appeared to have on minimal makeup and donned a pair of retro cat's eye sunglasses, while pulling her blonde hair back in a loose bun. 

Montana, who is pregnant with her first child, also opted for a casual look, wearing a loose-fit brown sweatshirt over her growing baby bump. 

The 33-year-old added a pair of pale pink bike shorts and completed the ensemble with white sneakers. 

She too had on minimal makeup and wore her red hair down around her shoulders in soft waves. 

The pals strolled along together after their gym session, chatting happily and laughing together at times.   

Jade recently resurfaced on social media to reveal that she has been hiding a private health battle. 

She returned to Instagram last week after vanishing offline in June, and shared a series of photos taken while she was lying in a hospital bed.

In a lengthy caption, Jade told her worried followers that she had undergone extensive surgery after being diagnosed with stage 4 endometriosis.

Deep infiltrating stage 4 endometriosis (DIE) is the most advanced and severe form of the condition, where tissue similar to the lining of the uterus grows more than 5 mm deep beneath the pelvic and abdominal lining, and invades surrounding structures.

Jade explained that surgeons found the disease in multiple organs, which were extensively excised during surgery, along with the removal of her appendix. 

Beginning her post by acknowledging that it has 'been a while' since she was active on her social channels, Jade said that she finally decided to go public with her medical struggles. 

'I'm a very private person and certainly not one to share anything personal on here, but I promised myself that, when I was ready, I would share this,' she wrote.

'And if this post can help just one girl on their journey, then it has done its job.'

Jade said that she was disappointed that, despite all the advancements in the modern world, there was still no cure for endometriosis. 

'The fact we're closer to flying cars than a cure for endometriosis, and still can't reliably detect it on a standard scan, absolutely blows my mind,' she wrote. 

'This experience has opened my eyes to just how many women are suffering, often silently, and how profoundly this disease can affect every part of their lives.'

Jade continued: 'I don't know exactly what change looks like yet, but I know I want to be part of it. 

'I'll keep talking, sharing and advocating until women have better answers, better treatment and a future that looks different.'

In a further post, Jade said that she realised something was wrong with her health when her body 'stopped making sense'. 

She had 'collapsed in pain and could barely walk' and suffered a burst ovarian cyst, which turned into 'persistent and debilitating pain and crazy blood sugar fluctuations'.

Jade went through 'endless blood tests, scans, ED visits, morphine injections, specialists and a lot of unanswered questions' and for a time doctors suspected she had tumours in her abdomen before she received an answer. 

'I was incredibly lucky to eventually find an amazing specialist who operated within two weeks of seeing me, despite us still not knowing exactly what they would find,' Jade explained. 

'I'll always be grateful to him for listening, taking my pain seriously and finally giving me some answers.'

While she found 'relief in finally having an answer', Jade still has a long way to go in terms of her recovery. 

'Some days I feel completely like myself, and other days my body reminds me very quickly that it's still healing,' she said. 

'I'm still rebuilding my strength, understanding my body, searching for answers and learning what life with endometriosis looks like moving forward.'

 Endometriosis is a painful condition where cells similar to those in the lining of the womb (uterus) grow in other parts of the body.

It affects around one in seven women of reproductive age in Australia, but the average time it takes to get a diagnosis is six to eight years.