Blood test hoped to reduce stillbirths
Researchers from Melbourne's Mercy Hospital for Women have worked out how to detect low oxygen levels in at-risk babies with a world-first blood testPT0M39S http://www.canberratimes.com.au/action/externalEmbeddedPlayer?id=d-2z008 620 349 December 9, 2013
Melbourne researchers have developed a blood test that could help prevent stillbirth, a tragedy that affects millions globally every year.
In a world first that has the potential to transform the management of complicated pregnancies and births, Mercy Health researchers have discovered a way to accurately measure a baby's oxygen levels inside the womb.
This has long troubled clinicians who say it can be difficult to diagnose and measure the extent of oxygen and nutrition deprivation in foetuses, a condition that leads to about half of the 2000 stillbirths in Australia each year.
Dr Clare Whitehead (right) with Rochelle Haralambous and her baby Tia. Photo: Jason South
Infants can also suffer serious injuries, including brain damage, from low oxygen levels during complicated pregnancies.
The head of Mercy Health's translational obstetrics group, Stephen Tong, said until now doctors mainly used ultrasound to estimate oxygen in the womb. However, he said, it was a blunt instrument that could not always be relied on in deciding when to deliver.
''Ultrasounds are good but they are not perfect and sometimes we time it too late and there is a stillbirth or the best guess is to deliver and we deliver early and the baby has suffered from the potential risk of prematurity,'' Professor Tong said.
But, in a breakthrough that has taken three years of work, Clare Whitehead, a scientist and clinician who works with Professor Tong, has found that when oxygen levels are low, fragments of genetic material called RNA leak out of the placenta and into the mother's blood. This is detectable with a simple blood test.
She said the RNA measurements could also be charted to show how much oxygen was lacking to determine how sick the baby was. The finding will be published in the prestigious medical journal BMC Medicine on Monday.
Dr Whitehead said although tests on about 100 women gave her confidence the technique worked, the team was now running a clinical trial involving about 180 pregnancies at seven hospitals.
''We'll get those results over the next few years, but the technology already exists so we could have a test within five years,'' she said.
''About one in 135 women is affected by having a stillbirth and of the stillbirths that happen, over 50 per cent of them are due to growth restriction that we haven't picked up.
''So if we can identify these pregnancies before the stillbirth happens and monitor their oxygen levels, we could prevent some of those deaths''.
The director of perinatal medicine at Mercy Health, Sue Walker, said such a test could have helped her time the birth of Tia Haralambous, who was born weighing just 517 grams. She said ultrasounds showed signs of oxygen and nutrition deprivation at 20 and 24 weeks' gestation.
Professor Walker said that during the 27th week of pregnancy she had to monitor Tia daily with ultrasound to try to predict when she would reach 500 grams to give her the best chance of survival outside the womb.
''For these babies, every day and every gram matters, as long as you can get it safely. The work Clare has done has taken us a step closer to making sure every one of those days and grams is a safe day,'' she said.
Tia's mother Rochelle Haralambous said a test that provided more certainty would have eased some of her fears as she waited day after day 18 months ago, hoping her baby would survive.
''It will certainly help other parents going through that,'' she said.