"(But) the deafening silence in the delivery room, where there should have been newborn baby cries, confirmed our worst fears," she said.

Bluey - the son she and husband Josh had nicknamed at seven weeks when he was the size of blueberry, and spent every day since desperately excited to meet - was stillborn at 36 weeks.

The day before, Holly had woken to find she could no longer feel Bluey moving.

An ultrasound later that day confirmed he no longer had a heartbeat.

"We were in disbelief. I just hoped that it was all a mistake, that they'd got it wrong somehow and our baby boy was going to be fine," she said.

"I feel a sense of injustice that Bluey doesn't get to live his life.

"He taught us the true meaning of unconditional love, but we will never really know him."

Holly and Josh are now the face of a campaign that hopes to save scores of parents from ever experiencing their heartache.

In Australia, six babies are stillborn each day, a rate that hasn't budged in 20 years despite huge medical advances.

That rate is 35 per cent higher than the best-performing countries across the globe.

Not all stillbirths are preventable, but many could be. That's a message the Ryans are hoping to share with as many expectant parents as possible.

Three simple actions have been proven to reduce the risk of stillbirth.

Firstly, pregnant women should sleep on their side after 28 weeks of pregnancy, something that research shows halves the risk of stillbirth, but only a third of Australians know.

Quitting smoking and avoiding second-hand smoke is critical too.

But Holly's best advice to expectant parents is for them "trust their gut" when it comes to their baby's health, and monitoring their regular pattern of movement is key.

"The message that was lacking in my pregnancy was getting to know your baby's movements, and any increase or decrease is something that could be a sign of distress," Holly said.

"We didn't know what we didn't know."

They have joined Still Six Lives - a coalition of pregnancy loss advocacy groups - in urging Australians to make the Stillbirth Promise, a pledge to share those three key actions to reduce the risk with their friends and social media circles, encouraging others to make that same promise.

"While the topic of stillbirth can be difficult to fathom for some, we must address the misbelief that there's nothing that can be done to reduce stillbirth risk," Still Six Lives spokeswoman and Red Nose chief executive Jackie Mead said.

"We are calling on the public to understand how they can help minimise the risk and to commit to having this most important conversation with those closest to them."

Australian Associated Press