Doctors are to hold talks over whether to operate this week to separate newly-born conjoined twins Faith and Hope Williams, it is reported.
The babies, who were delivered by Caesarean section last Wednesday, are being cared for in London's Great Ormond Street Hospital for Children.
Their mother Laura made medical history by becoming the world's youngest mother of conjoined twins at just 18.
She said the moment she first saw the children at University Hospital, London, was "brilliant" and "amazing". She told the Mail on Sunday: "After I came round from the operation they wheeled me in to see them. They were so beautiful, I couldn't stop looking at them. After everything everyone said, I'm so glad we've proved them all wrong."
Doctors warned Mrs Williams and her husband Aled, after a 12-week scan revealed the babies were joined from their breast bone to the top of their navels, that they might not survive.
But the couple, from Shrewsbury, Shropshire, refused to have a termination.
Mrs Williams said: "The night before the operation I couldn't sleep. I prepared myself for the worst, just in case, but from the first time I felt them kick, I thought they were going to be OK. And they're still here. They're little fighters."
Nuffield Professor of paediatric surgery at the hospital, Agostino Pierro, said the children's hearts had significant abnormalities that could require surgery.
He added: "The current concern is that the two hearts and the joined circulation raise a risk that the children might suddenly deteriorate and need emergency separation surgery.
"Although the team would prefer to leave surgery until the children are older and stronger, increasingly we believe that this may be risky."
