A new technique that bounces laser light off brain cells to monitor the amount of oxygen reaching a fetus could help prevent brain damage and reduce the number of Caesarean sections, a researcher says.

The technique has shown good results in tests on 12 patients at the University of Bonn Gynecological Hospital, said Dr. Stephan Schmidt, who heads the research team. "Its main advantage is that its a gentle monitoring method which can give continuous readings without touching the fetus."We still have a long way to go before we make definite conclusions, but the preliminary results are very promising."

The relatively cheap technique - Schmidt's model costs about $43,000 - beams extremely low levels of harmless infrared light into the fetal brain. The light reflected back provides information about the supply of oxygen in brain cells; the information is displayed graphically on a desktop computer.

"It is extremely important to us to be able to gauge the level of oxygen in the tissue cells as often as possible," Schmidt said. Earlier techniques required blood samples from the fetus, which "has the disadvantage of being a single-point test and has to be repeated at short intervals.

"A continuous record is far more preferable and less cumbersome."

In 20 out of 100 cases, he said, heart monitors indicate the possibility of oxygen deficiency, but only five of those 20 have symptoms that would actually require Caesarean delivery, he said. "With our technique we hope to be able to determine which of those infants do not really require a Caesarean section."

Oxygen deficiency is the most common cause of death before, during and just after birth and is the main contributor to fetal brain damage, he said.