Baby Elsie was born with a "giant" omphalocele where her stomach, liver and intestines grew outside her tiny body in the umbilical cord.

Parents Hannah, 27, and Simon Cox, 31, braced for the worst when doctors told her Elsie's condition "may not be compatible with life" at the 12-week ultrasound.

"When we were told about the complexities associated with the omphalocele and the possibility of our baby not being compatible with life, that was hard to hear," Mrs Cox said.

"We understood her condition was rare, unusual and complex. I was told it would be a hard road and that her organs growing outside her body would affect her chest, lungs and spine when she was born."

The couple refused to give up hope, despite knowing Elsie faced a six to 12-month stay in hospital after her birth.

"It was a bleak time - we were trying to be excited about having our first baby, but the prognosis wasn't good.

"It was hard to stay optimistic at times."

On May 30, doctors delivered Elsie in a complicated caesarean section to ensure her organs did not rupture during birth.

"We needed to be careful with Elsie to not put pressure on her abdomen or the umbilical cord during the delivery," Mater Maternal foetal Medicine Fellow Dr James Aridas said.

Omphaloceles affect one in 4200 live births, but "giant" ones are rarer. One in five babies born with giant omphalocele does not survive.

Elsie's omphalocele was one of the largest ever treated at the Queensland hospital, according to Mater Director of Neonatology Dr Pita Birch.

"There was a plan to attempt at least a partial closure of Elsie's abdomen, but she was too sick and had a number of respiratory problems at birth," Dr Birch said.

Six months on, Elsie's condition has affected her respiratory system, as her ribs and chest have formed into a cone shape, and she may require surgery when she gets older.

"Her tummy is pretty much flat now; she has a little bump which looks like a hernia, but it's actually just her intestines still moving down. Her body still needs some time to heal," Mrs Cox said.

The family is counting the days to celebrate their first family Christmas with Elsie.

"What we have gone through this year has felt like a lifetime. I look at photos and see how far Elsie has come and think 'she's our miracle'," Mrs Cox said.

Australian Associated Press