Erin McNaught on her post-birth infection: 'I had no idea how serious it can be.'

Last month, Australian model, actress and presenter Erin McNaught welcomed her second child with her rapper husband Example.

Posting on Instagram, the 35-year-old revealed that she was almost back in the hospital just three weeks after giving birth after she was diagnosed with mastitis, an infection of the breast tissue.

“CAUTION: LONG POST ABOUT BOOBS AHEAD!” she shared with her 161,000 followers.

“My mastitis returned with a vengeance over the weekend.

“Wanted to talk about it a bit as I had NO IDEA 1) how painful it can actually get, and 2) how serious it can be!”

Ennio Stanley Gleave ❤️ He arrived this morning (39w) after a relatively quick natural and drug-free birth ???????? 3.3kg Both of us happy and healthy ☺️ Just as overwhelming second time round ????????????

A post shared by Erin McNaught (@mcnaughty) on Sep 12, 2017 at 2:06am PDT

The former Miss Universe shared that she had begun to feel “pretty crappy” last week.

“Really achey all over, super fatigued and had a splitting headache… basically flu symptoms,” she wrote.

She shared that she suspected “mild mastitis” but thought it has cleared up, and instead put her symptoms down to a lack of sleep and being “run down” by caring for a newborn baby.

By Saturday afternoon, however, Erin said she was in “agony”.

Mr Cheeks II ???????? #1WeekOld

A post shared by Erin McNaught (@mcnaughty) on Sep 19, 2017 at 2:43am PDT

“I could barely even stand up… Turns out it was mastitis and I was going downhill, FAST,” she wrote.

When she called an emergency call-out doctor to prescribe her antibiotics, she was told that if she had waited until the next morning for treatment, she would have had to be hospitalised.

“Imagine being [back] in hospital with a newborn baby, hooked up to an IV, simply because you ignored your symptoms and tried to push through,” she said.

Erin is using her experience as a way to warn other mums not to ignore any symptoms they believe may be mastitis.

“If you’re a new mum and you don’t feel right, PLEASE, get yourself checked out!” she wrote.

LISTEN: On our Year One podcast, Holly Wainwright, Christie Hayes talk the great breast vs. bottle debate.

Other mums shared their own stories of being hospitalised after suffering mastitis.

“I had same thing happen one week after going home with bub,” one woman wrote.

“I had to take her back in with me, trying to breastfeed her and hooked up to IV antibiotics with no sleep and trying to recover from a c-section. Was the absolute worst time but made me realise how strong I actually am.”

The Australian Breastfeeding Association recommends that if breastfeeding mums suspect they have mastitis, to seek medical attention.

Symptoms may include flu-like symptoms like shivers and aches, and a sore breast that may be swollen, hot and painful.

Seeking treatment as soon as possible is the best course of action.