A baby who was the size of an apple when she was born has been released from hospital in the US.

The baby girl, nicknamed Saybie by hospital staff, weighed in a 245g when she was born at the Sharp Mary Birch Hospital in San Diego last December.

Her mother was only 23 weeks pregnant when she began feeling ill and was rushed to hospital to be told she had a condition called preeclampsia – which can put the lives of both mother and baby at risk.

In a video released by the hospital, the mother, who does not wish to be identified, said: "They had to deliver her really quickly and I kept telling them that she's not going to survive, she's only 23 weeks."

Sadie at the Neonatal Intensive Care Unit. Image: Mary Birch Hospital

Micro preemie

She said the day Saybie was born was the scariest of her life.

“They told my husband that he had about an hour with her and she was going to pass away,” she said.

“But that hour turned into two hours, which turned into a day, which turned into a week.”

Doctors said Saybie’s survival is down to her fighting spirit and the fact that she suffered no serious complications after birth.

Babies born before 28 weeks are known as ‘micro preemies’ and often face complications, including brain bleeds and lung and heart issues.

Saybie “graduated” from the Neonatal Intensive Care Unit in May. Image: Sharp Mary Birch Hospital

Miracle

The nurses who cared for Saybie have labelled her a miracle, noting that her survival was “completely against all odds.”

Emma Wiest, one of the nurses featured in the video, said when she heard about Saybie “it sounded unbelievable.”

“I mean she's about half of the weight of a normal 23-weeker,” she said.

“So I went and saw here and you could barely see her on the bed because she was so tiny.”

Saybie at home after she was released from hospital in May. Image: Sharp Mary Birch Hospital

Strong

Earlier his month, Saybie was discharged from the Neonatal Intensive Care Unit as healthy five-pound baby.

“I just want her to know how strong she is,” said Ms West.

“If she can start off where she was and do as well as she is doing, there is nothing she can’t do.”

According to the Tiniest Babies Registry, maintained by the University of Iowa, Saybie is the tiniest baby ever to survive.