Little Lucas, who experienced complications soon after birth due to a blood condition, was at risk of brain damage or going deaf.

The only treatment was a life-threatening exchange transfusion.

"I was thinking, am I getting ready to say goodbye to my baby," Mrs Lawler said.

After undergoing the uncommon procedure at John Hunter Children's Hospital twice within his first three days of life, Lucas showed enormous fight to make a remarkable recovery.

"We probably do about one of these procedures every year," neonatologist Paul Craven said.

"It's unusual to do it twice."

Yesterday Lucas was enjoying well-deserved time at home in Marks Point with mum, dad and sister Holly, 2.

Lucas was born an apparently healthy baby on October 5 at Newcastle Private Hospital.

But about seven hours later, displayed severe jaundice.

The chemical making him appear jaundiced, bilirubin, was present in such high levels that Lucas was at risk of brain damage or deafness.

"At that time [the birth] you feel like the proudest person on earth," Mr Lawler said.

"Nothing could break you down. Suddenly you've gone from the emotion of happiness to fear.

"We were quite devastated, in a way, not knowing what's going on. We thought we had a healthy baby."

The cause was antibodies in Lucas's blood, passed from Mrs Lawler.

The antibodies were created during her first pregnancy, because mother and baby had different blood types.

Newcastle Private Hospital staff transferred Lucas to the neonatal intensive care unit.

During the transfusion, his blood was replaced twice over with new blood over the course of several hours.

"In this situation what we then do is we're taking all the dangerous bilirubin away and the antibodies away and giving him fresh blood so he's not so jaundiced and therefore not affecting his brain," Dr Craven said.

Tests showed the bilirubin levels were not permanently reduced, so the procedure had to be repeated.

"This antibody he initially had in his circulation was so strong we had to do the whole thing again," Dr Craven said.

The transfusion had a mortality risk, but left unchecked, the condition's long-term consequences were severe, Dr Craven said.

The second transfusion, a day later, was a success.

Lucas was discharged after six days in hospital.

Lucas has suffered no hearing loss, and his brain development will be monitored for at least a year.

"His recovery's been just incredible," Mr Lawler said.

Mrs Lawler said Lucas was doing all the normal baby things.

The couple praised the staff at both hospitals.

"Thank God the doctors are world-class in there," Mr Lawler said

"It was dramatic for us at stages. But I think we just put our trust in the doctors and nurses."

Mrs Lawler said the staff looked after her boy well.

"We're just happy we're all home and pretty healthy," she said.