A speedy new biosensor to indicate oxygen starvation in unborn children could help prevent women in labour from undergoing unnecessary caesarean sections, its inventors claim.
Dangerous oxygen starvation, or 鈥渇etal hypoxia鈥�, currently takes time to detect so many doctors proceed to caesarean surgery rather than risk a child鈥檚 life. But such operations also carry health risks for the mothers.
Nick Dale, a neuroscientist at the University of Warwick, UK, decided to look a faster, more efficient test than the current practice of analysing the pH of the baby鈥檚 blood 鈥� a marker of hypoxia 鈥� in a blood-gas analyser.
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Over 30 years鈥� worth of research has shown that the chemical hypoxanthine is a marker for hypoxia, so he developed a biosensor to measure blood hypoxanthine levels. The biosensor showed good accuracy in tests using horse blood and now his team is designing a prototype to be tested by doctors and midwives in preliminary human trials in five UK hospitals.
Two-minute test
The team plans to use fetal blood left over from the current pH test sample 鈥� taken from the unborn infant鈥檚 scalp using a scalpel introduced via a tube into the mother鈥檚 vagina. Researchers will compare the prototype sensor鈥檚 performance with that of the blood-gas analyser.
鈥淪ometimes the blood-gas analyser does not accept the sample 鈥� for example if there is an air bubble in it 鈥� so then you need to get another. You can imagine quite a lot of critical time could go by before you get a result,鈥� says Dale. 鈥淲ith our test you get a result in a maximum of 2 minutes.鈥�
The biosensor works by using an enzymatic reaction to produce a signal in proportion to the amount of hypoxanthine present in a sample. The team hopes to be ready for the human trials in 18 to 24 months, working with a company called Sarissa Biomedical Ltd.
Everybody gains
If widely adopted, the biosensor could lead to a decrease in the number of unnecessary caesareans, Dale hopes. About 23% of 575,900 live births in England were caesareans in 2003 鈥� with more than half of those done as emergencies, according to the UK鈥檚 department of health.
鈥淚n some units the c-section rate is approaching 30%,鈥� notes Dale, 鈥渁nd it shouldn鈥檛 be more than half that, really. If we could get that rate down, everyone would gain and there would be a tremendous economic benefit too.鈥�
Dale hopes the new biosensor could eventually be used as a continuous monitor for hypoxia by attaching it to the unborn baby鈥檚 scalp.
