A “miracle” baby girl has spent her first two nights at home after becoming what her doctors believe is the world’s youngest patient to survive major abdominal surgery.

Abiageal Peters is expected to lead a normal healthy life after being saved in pioneering operation her parents and doctors say was only possible under the NHS.

“She is always going to be our little miracle,” her mother, Louise Peters, said from her home near Esher, Surrey, with the sound of Abiageal gurgling in the background.

Abiageal was born in October 2016 at St Peter’s hospital, Chertsey. She was three months premature, after a gestation of only 23 weeks. Peters was warned her baby had little chance of overcoming a severe gut condition known as perforated necrotising enterocolitis. Her intestine was torn in three places and her stomach had started turning black.

Facebook Twitter Pinterest Louise and David Peters with daughter Abiageal. Photograph: Family handout/PA

An operation at a specialist neonatal unit at St George’s hospital, London, was Abiageal’s only hope, despite the risk of surgery on such a young and small baby. She weighed just 609g (1lb 5oz).

“She would have been dead without the surgery,” Peters said. “She was deteriorating so badly at that point. She was struggling to breathe and her skin was turning black. We knew she had a day or two left if that, if they didn’t operate.”

Consultant Zahid Mukhtar, who led the operation, said it was extraordinary that Abiageal managed to pull through surgery. “We have trawled the literature and couldn’t find anyone who has been operated on at that early an age and survived. Her story and her recovery has been really remarkable.”

Speaking to the Guardian, he said: “She was smaller than my hand when we operated on her. But it was her prematurity that was so unusual – her organs were so fragile and jelly-like that as soon as you started operating, even with our small instruments, everything started to bleed or fall apart.”

He spoke of the team’s pride in saving Abigail. “It is beyond the craft of surgery, something more has to come into it, to push boundaries like this. It is an amazing achievement for our team, so we are really proud. The fact that four months later she is a really healthy child, with a good brain, is amazing considering how premature she was.”

Peters, a financial analyst who grew up in South Africa, said: “We can’t thank the doctors enough. I don’t know if she could have survived outside the NHS. Some countries don’t even think about helping babies who are less than 25 or 26 weeks. She would have had very little chance.”

“I come from a country where you have to pay for every cent of your medical aid. This country has been phenomenal. I think the NHS is absolutely wonderful.”

Peters and her British husband, David, also have a two-year old daughter, Tara. “My first daughter was such an easy pregnancy that I just took it for granted that my next baby would be as easy,” she said.

Peters added: “The beginning was especially stressful, but my baby is a fighter. Then it was four months of waiting for her come off breathing support and sort out her feeding. There have been lot of hurdles, infections, blood transfusions along the way.

“Other mothers who have this happen to them, should know there is a chance – don’t give up, these little babies are so strong.”

She added: “It has been wonderful to have her home, but there are all the usual niggles of getting a new born to sleep.”

Mukhtar said the success of the operation demonstrated the NHS at its best.

“Despite the financial pressures and morale challenges, the staff working in the NHS are amongst the best in the world,” he said. “They are really pushing the boundaries. Any patient that comes into our system gets the best we can do for them. It is mindset that is different from other places in the world where I have worked. It is a real honour for me to me working in this system.

“Outside the NHS there is no chance she would have survived. Any child in a private hospital born this prematurely would have been transferred to the NHS immediately.”

Mukhtar, who was born in mountain village in Pakistan, said he wanted to become a doctor after his three-year-old sister died from diarrhoea. “From a simple thing like that she died, because there was so little help for sick kids. From then I have tried to never give up on a child and do whatever is possible.”

He added: “I was a village kid with uneducated parents and yet this country gave me the opportunity to follow my dream and now I am able to give back that education and possibility to affect people’s lives so profoundly. It is a real shame that people are so suspicious of people coming here from other countries.”