Doctors warned parents Michelle and Darryl Lewis that their unborn baby was unlikely to survive and so advised a termination at 21 weeks.
But the couple, from Tunbridge Wells, Kent, refused and Michelle, 32, gave birth to Riley. The tiny tot had surgery at just eight hours old, followed by four more operations – and then he started on his road to recovery.
He made such good progress that he was even well enough to be a pageboy at his parents' wedding just seven months later.
Although Riley will need to have further operations to replace heart shunts as he grows, medics are confident that Riley will be able to lead a normal life Michelle told her local paper: "The surgeons told us that it is nothing short of a miracle that Riley is here at all.
"Doctors told us having one heart defect was unlucky, but six was unheard of.
"They said he probably wouldn't make it through the pregnancy, and even if he did, wouldn't survive long after birth.
"We were devastated - but Darryl and I just turned to each other and we knew straight away there was no way either of us was going to give up on our baby.
"The rest of my pregnancy was terrifying - I lived in fear of something going wrong.
When I went into labour, Riley's heart stopped every time I had a contraction - we nearly lost him so many times.
The couple had no idea there were any complications with Michelle's pregnancy until their 21 week scan.
They were warned their unborn child was suffering from back-to-front valves, a large hole in the heart, as well as various conditions that made his arteries thick and made it difficult for blood to pump around the body.
Michelle said: "The doctors said our baby's heart was struggling to pump blood around his body, and he had so many complications he wouldn't live.
"They said they'd never seen anything like it - having so many conditions was totally unheard of.
"They took us into a little room and advised us to terminate the pregnancy - but there was no way we would even consider it.
"I was induced and went into labour on Christmas eve, and it lasted 15 terrifying hours before doctors decided to perform an emergency caesarean on Christmas day 2010.
"I heard this little scream and the nurses held him up for me to see before he was whisked away. I remember seeing his big beautiful eyes and just pleading that he would keep fighting."
Michelle added: "After his first operation, the surgeon came out and said to us he had no idea how Riley was still here - he said it was a real miracle."
Despite needing a further three operations in the last 12 months, doctors are amazed by Riley's progress - and say at 18 months old he is doing much better than expected.
He will need to have further operations in the future to replace shunts as he grows, but medics are confident that Riley will be able to lead a normal life.
Darryl said: "Riley is our little superstar. I look at him and Michelle every day and just think how lucky I am to have them both."