Lincoln Ryman weighed just 1lb 2oz (530g) when he was born 11 weeks early along with his big brother, Byron, who weighed 3lb 6oz (1.5kg).

Doctors at the Royal Hospital for Women in Sydney intervened to deliver the boys when they discovered a relatively rare pregnancy complication.

Blood was flowing from Lincoln to Byron, putting both in danger.

We didn't think we were going to have them both.

Nicole Ryman

Their mother, Nicole, was told to prepare for the worst when it was decided the best option would be for her to deliver the boys in the 29th week of her pregnancy.

Doctors gave Lincoln a one in three chance of survival because he was so small.

Despite his very low weight and needing heart surgery after he was born, Lincoln is now thriving, as is his brother.

Poor survival chances

Nicole and her husband Todd, who conceived through IVF, said their first weeks of parenthood had been nerve-racking.

Mrs Ryman said: "We've been on top of the world because we didn't think we were going to have them both.

"We've had a few scares on the way but they are pretty well going forward now and I know I'm going to be able to take them both home."

She is expected to take Byron home at the end of next week. Lincoln will stay in the hospital's newborn intensive care unit for another month.

Dr Parag Misha, who has been looking after the twins, said about Lincoln: "The chance of survival I gave him was less than 30% because he was so small.

"Hopefully he will soon start gaining weight much more quickly and get nearer and nearer his brother."