Dental X-ray risk to babies

Women who have dental X-rays while pregnant are three times more likely to give birth to an underweight full-term baby, research shows today.

The US scientists who made the discovery have called for a larger study into the possible effect of X-rays on birth weight.

Professor Philippe Hujoel, from Washington University School of Dentistry, said: "Researchers had assumed that only direct radiation to the uterus or foetus would be harmful. When we first noticed this association, we were very surprised."

The reason for the link is still unclear. One theory is that X-rays may affect hormonal mechanisms in the head and neck region.

Professor Hujoel said the findings, reported in the Journal of the American Medical Association, should not stop women having dental X-rays when necessary.