A healthy baby boy was born days after cardiologists performed a world-first heart operation - while he was still in the womb.

Parents Christopher Havill (27) and Kristine Barry (25) welcomed baby Sebastian into their lives just five days after surgeons performed a risky heart operation, known as a balloon atrial septoplasty, while he was still in-utero. Routine prenatal checkups had revealed that the baby boy had a significant congenital heart defect, meaning that the two main arteries of his heart were reversed. The case was said to be particularly complex because the interior walls of his heart were sealed shut, with blood unable to flow between the chambers to pick up oxygen. In what was hailed as a surgical world-first, cardiologists used a needle to insert a balloon through mum Kristine's uterus, into Sebastian's heart and make a small hole to open up the heart's interior wall, allowing oxygenated blood to pass through. Dr Greg Ryan, head of the foetal medicine programme at Mount Sinai Hospital in Toronto, explained the procedure to CBC News:

"We had a baby with the two sides of the circulation that were not communicating. There was no opening between the upper chambers and the lower chambers and the vessels were coming off the wrong side. So what we had to do was to create a communication to allow the blood to mix."

New mum Kristine told the news station that they were prepared for the worst:

"They always prepped us for a blue baby. They always said that he was going to be blue and not vocal because of the lack of oxygen."

Thankfully, little Sebastian was born "all pink and screaming" and dad Christopher even got to cut the umbilical cord. The miracle baby's cardiologists say that Sebastian now has every chance at a normal and healthy life.