A mother-to-be inspired her electronic engineer husband to devise a new low-cost baby scanner which could save hundreds of thousands of lives.

Sonar expert Jeff Neasham used cheap components to make a hand-held scanner which can plug into a laptop and produce pictures of the unborn child on the computer screen.

The Newcastle University lecturer's device could be manufactured for £30-£40 compared to the ultrasound machines in UK hospitals which cost £20,000 to £100,000. That means the scanners - devised by Mr Neasham and research associate Dave Graham - would be much more affordable for developing countries.

The 39-year-old father-of-two was inspired when his wife Zoe was expecting their first daughter, who is now seven.

He said: "The idea came from my own experiences sat looking at the pictures of our unborn child. It was my wife's idea - she suggested we could apply what we knew to make them more affordable and make a low-cost system for lots of people around the world.

"My background is in sonar which is very similar to ultrasound. I started to have a think and I just treated it as an interesting engineering challenge, to see what was the absolute minimum cost of components needed to produce any kind of useful image.

"We ticked along on a shoe-string budget then we started to get some promising results and so we got funding to build a prototype. We used techniques we use in sonar signal production to simplify the circuitry and transducer design while trying to maintain a reasonable resolution in the images.

"We are not at the stage where we can completely match the image quality of a really high-end scanner but we are getting closer and closer."

The technology could have a major life-saving effect as UN figures show 250,000 women die every year from complications during pregnancy or child birth. Many deaths are avoidable, but for a lack of equipment.

Mr Neasham said his images could easily show if a baby was in the breach position, but the definition was not yet high enough to determine the sex. There were other uses away from obstetrics, such as diagnosing gallstones and liver problems, but health professionals will determine what else could be done with the technology.