Blood test breakthrough for unborn babies
Scientists have developed a genetic test which can help diagnose a potentially fatal blood disorder in babies while they are still in the womb, it emerged today.
The technique has been designed to help pregnant women with Rhesus disease, which occurs when the mother's immune system reacts against her baby's blood type.
Under the new procedure, doctors are able to extract the unborn baby's DNA from a sample of the mother's blood.
This allows them to determine the developing foetus' blood group just a few weeks into the pregnancy.
The team behind the pioneering blood test are now hoping it could be used to identify and treat other inherited genetic diseases in unborn children.
The research and development of the technique was carried out by a team from the Blood Transfusion Service at Southmead Hospital and the University of the West of England, led by Professor Peter Soothill, from the University of Bristol.
"It is now possible to do genetic tests on unborn babies from their mother's blood," he said.
"This is invaluable in terms of treating Rhesus disease, but what is really exciting is the opportunities it has for the future.
"What is surprising is that there are free-floating DNA in the mother's blood. That could have important health implications."
Rhesus disease occurs in about one in a hundred cases of pregnant women with Rhesus negative blood having babies with Rhesus positive blood.
In the worst instances of the disease, the mother's body produces antibodies which attack the baby's red blood cells.
This causes the developing foetus to become anaemic and can ultimately lead to miscarriage or stillbirth.
Rhesus disease had been difficult to detect until late on during a pregnancy, and mothers deemed to be at risk often had to undergo a amniocentesis test.
This carries a risk of miscarriage as well as making the disease more severe.
But Prof Soothill's new procedure means mothers can now be diagnosed at an early stage and not have to undergo the high risk test.
It also means the baby can be given regular blood transfusions through the umbilical cord to ensure it remains healthy and does not have to be born prematurely.
Professor Soothill said about 17% of all pregnant women had Rhesus negative blood, but that only one in 100 of these who then had Rhesus positive babies developed the disease.
He said about four years work had gone into developing the procedure, which he added, was now attracting interest from all over the world.
"There is nowhere else in the world that is doing this at the moment," he said.
"We have had blood samples from the United States and other parts of the world."
The professor said he hoped the test, which has so far been carried out on 140 women with 100% accuracy, would soon become more widely available.
He said it could ultimately be used to reduce the number of intrusive procedures carried out during pregnancy.
Rachel and Dave Lewis, from Yatton, Bristol, are one of the first couples to benefit from the pioneering new procedure.
The couple's first child, three-year-old Rohan, had to be born prematurely by Caesarean section after Mrs Lewis was identified late on in her pregnancy as having Rhesus disease.
Rohan had become anaemic and had to spend several weeks in intensive care and under phototherapy lights before he was allowed home.
When Mrs Lewis fell pregnant with the couple's second child, Alanna, she was offered the pioneering test after just a few days by staff at St Michael's hospital in Bristol.
The test showed again that she had Rhesus disease, but this time doctors were able to monitor her condition and carry out regular blood transfusions to ensure the baby was kept healthy throughout the nine-month term.
"This time has been completely different," said Mrs Lewis. "With Rohan, I was discharged and had to go home without my baby. I was a nervous wreck.
"With Alanna, I have been monitored right throughout the pregnancy, which gave us so much more confidence.
"She has not needed any special care, she feeds better - she is just a normal healthy, happy baby. The last time was traumatic, this time I felt safe."
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