Surgeons were operating last night to separate week-old conjoined twin girls after their condition began to deteriorate.
The girls, Faith and Hope, were born to Laura Williams, 18, on Wednesday last week but concerns developed over their condition on Monday night, prompting surgeons to act.
The twins are joined from the breast bone to the navel and have separate hearts. However, they share a liver and some major blood vessels.
The operation was planned for later in the week but surgeons began operating at lunchtime yesterday. If either or both twins survive the surgery, they will face a crucial few days and will require close monitoring in intensive care. The separation is equivalent to removing a huge mass from each twin amounting to roughly 50 per cent of their body weight, and the heart and other organs must adjust to the smaller size.
A spokeswoman for Great Ormond Street hospital said yesterday: "The separation of Faith and Hope Williams has been brought forward and is currently taking place, after some concerns developed last night. Obviously, the final decision about separation surgery was made by the family."
The spokeswoman added that Mrs Williams and her husband Aled, 28, from Anglesey, Wales, wanted to thank all the hospitals involved in their care.
The babies were born at University College hospital, London, and transferred later to Great Ormond Street Hospital for Children, which has a worldwide reputation for successfully separating conjoined twins.
Agostino Pierro, professor of paediatric surgery at Great Ormond Street, warned at the weekend that the girls' hearts had congenital abnormalities that could require emergency surgery.
Large blood vessels ran from one child to the other and were joined at the liver and the intestine, he said. Separating the liver is thought to be relatively simple but dividing and sealing the large blood vessels presents a greater challenge. The babies have all their own limbs and together weighed 10lb, 8oz at birth.
Mrs Williams made medical history by becoming the world's youngest mother of conjoined twins. She and her husband found out about their children's condition at her 12-week scan.
They were told by doctors that the babies might not survive and advised to have the pregnancy terminated but they refused. Mrs Williams said: "We knew conjoined twins rarely make it through the first 24 hours, and we could see that one girl was a bit smaller than the other so we called the little one Hope and the bigger one Faith."Reuse content