She's Miracle by name and miracle by nature. The newborn daughter of a Logan couple has been called Australia's most premature baby to survive.

Makerita Miracle Tanuvasa initially weighed barely 350 grams - less than the weight of a soft drink - after being delivered at 21 weeks and three days.

Mum Annrose and dad Misi Tanuvasa are still overwhelmed at their baby girl defying the odds, and leaving them and hospital staff in awe.

"I took one look at her and I was like, 'There's no way she's gonna make it'," Annrose told Nine News Brisbane.

It was so touch and go that she had to spend the first 14 weeks in the Intensive Care Unit.

Mum and dad were not even allowed to physically touch her until she reached four weeks old.

Makerita has also only been allowed to leave the hospital this month - four days after being taken off an oxygen tube - since she was born almost five months ago.

"She was about like hand-size, like our palm," Misi recalled.

"We weren't able to hold her...she was very, very small."

She arrived in the world on March 25 and has since been under around-the-clock care, first at the Royal Brisbane and Women's Hospital - while her parents stayed at the nearby Ronald McDonald's House - and then at Logan Hospital.

So small she was - at one stage, just a few hours after her birth, Makerita fell to just 315 grams - that Annrose only discovered she was pregnant five days prior to her baby girl's arrival.

It means that Makerita is not only believed to be one of the tiniest babies born in the country, but she's only four days shy from becoming the most premature recorded ever in the world.

"Even the doctors couldn't explain how she was able to survive everything she's gone through," Misi added.

She was so premature that resuscitation would normally not have been an option.

For the devout Christians of the Samoan diaspora, their first cuddle with their miracle coincided with Palm Sunday, a major day on the Christian calendar marking Jesus Christ's arrival in Jerusalem shortly before his crucifixion.

Her eventual discharge to the family home was a milestone that for so long had appeared out of reach.

"The sonographer (first) told us that we were about 22 weeks pregnant," Annrose recalled.

"But I told her, I said, 'That's impossible', and she was like, 'Why do you think it's impossible?', and I said, 'Because I had a miscarriage in December'.

"She said, 'Well, maybe you had a twin, and you miscarried the twin?'."

Annrose has taken to social media over the months to inform family and friends on the progress of Makerita.

"It was still exciting to finally walk out those doors...hopefully for good," Annrose wrote recently.

"Thank you, Jesus!! Thank you to all who kept this lil girl in your prayers.

"We have a story to tell Makerita, and, yes, we definitely will share it."

Along the way, Logan Hospital announced Makerita was its baby of the week back in July after she spent her first 100 days of life contained to healthcare facilities.

"At the beginning of this journey, we all went day by day, hour by hour, minute by minute," Annrose shared online.

"The room was always just quiet and seemed so dark.

"As the days went by and she grew more stronger and tolerated things given to her a lot better, the room got brighter and the conversations were all about her future.

"Thank you, Jesus, for the medical team here at RBWH; Lord bless them!

"For 100 days, I have watched them be so tender and loving towards all the babies."