Published on May 19, 2008 at 6:37 AM
Danish and American scientists suggest that using mobile phones while pregnant may increase the risk of the child developing problems such as hyperactivity.
Mobile phones have also been linked in other research with brain cancer.
The researchers from Aarhus, Denmark and the University of California in Los Angeles say the use of handheld telephones by pregnant women could make the child more likely to develop behavioural problems and these risks increased with the amount of phone use and potential radiation.
The researchers conducted a study of 13,159 children in Denmark born in the late 1990s and found that that mothers who used handsets were 54 per cent more likely to have children with behavioural problems and the figure further increased to 80 per cent when the children also later used mobile phones themselves.
While they say the the results "should be interpreted with caution" and checked by further studies, it has very real public health implications as just using mobile phones just two or three times a day is enough to raise the risk of hyperactivity and emotional problems.
While other research has found that radiation from mobile phones only penetrates one or two centimetres into the skin and does not reach the unborn child, it has been shown to affect levels of melatonin, a sleep- controlling hormone that mothers pass to unborn babies through the placenta.
A link has also been suggested between children being left unattended for long periods and later behavioural problems.
The research will be published in the medical journal Epidemiology in July.