Sophie Delezio gave birth to her son in her 'most hated space in the world'

In the first accident, in 2003, an elderly man suffered a seizure and his car slammed into Sophie's daycare centre in Sydney, the vehicle landing on her and igniting. Then, only 2-and-a-half, Sophie suffered third-degree burns to 90 per cent of her body. She lost both her legs below the knee, her right hand and her right ear.

Then, when Sophie was five in 2006, the unthinkable happened. A driver, blinded by the sun, hit Sophie's stroller as she was being pushed across a pedestrian crossing. She was thrown 18 metres into the air and suffered internal injuries and a life-long brain injury. She also lost her sense of smell.

Nearly 20 years later, Sophie is now 24 and married to Joseph. They have a nearly 15-month-old son, "adventurous" Frankie.

When Sophie walked into Parliament House on Tuesday, it was as a mum rather than as that little girl so many Australians held so dear to their heart.

Sophie was the keynote speaker for Perinatal Mental Health Week, which draws attention to the mums and dads who suffer depression or anxiety during pregnancy and/or in the first 12 months after their child's birth.

Sophie, who has been in and out of hospitals her entire life, enduring hundreds of surgeries, told the audience she knew one thing when it came time to give birth to her first child - she did not want a cesarean section.

"PTSD, to me, comes out in mysterious ways. It's not like what you see on television. For me, it was facing an operating theatre," she said.

As "luck - or life - would have it", Sophie did have to have a c-section.

But she was guided gently by her obstetrician, who knew she "was petrified" of being back in an operating room.

"So with a rush of adrenaline and some Taylor Swift song playing in the background, my son was born in my most hated space in the world," Sophie said, on Wednesday.

"But with the love and care and kindness of this medical team around me and my beautiful husband, it was manageable."

It was just Sophie's first taste of the ups and downs of parenthood.

"When people ask if becoming a parent is what I expected? No. You have no control of how your child's going to come, when they're going to come, what they're going to be like, how they're going to sleep. That is parenthood to a 'T' but that is also life," she said.

"You don't know when unexpected challenges are going to be thrown at you and you just have to learn to roll with the waves."

Sophie said parenthood made her realise it was OK not to have it all figured out.

"It's OK to be overwhelmed and confused and not understand a single thing but to feel this immense mix of relief, fear, exhaustion, wonder and overwhelming love all at once. It's OK to take it one hour at a time. Because that messy and beautiful and unpredictable and the more we talk about truths, the less alone everyone will feel in it."

Sophie showed her honest approach to being a mother when she posted emotionally about her exhaustion when Frankie was eight months old and not sleeping.

She was worried she might be judged, that people might think she was "failing" at motherhood, but instead found she wasn't alone.

"All the mums were just supportive and it was just nice knowing you weren't the only one going through it," she said.

Perimental Mental Health Week brings together a range of organisations in the sector, including the not-for-profit Gidget Foundation Australia, which says perinatal depression and anxiety impacts around 100,000 Australians each year.

Free mental health centres are being set up as a result around Australia - including in Canberra.

The federal government and the Gidget Foundation will operate a new perinatal mental health centre to be established in Tuggeranong and opened by 2026.

The centre will provide local parents with free, personalised mental health support, if they have a referral from a GP and a mental health care plan.

Gidget Foundation CEO Arabella Gibson, who was at Parliament House on Wednesday, said stories such as Sophie's helped new parents to understand they weren't alone and might need help, whether it was from family or friends, or from professionals.

"Once we start to open that conversation and to build that village of support around us, that's really critical," Ms Gibson said.