SCIENTISTS have discovered new clues to a pregnancy complication that leads to the deaths of hundreds of babies each year in the UK.
It is hoped that the research into the causes of pre-eclampsia - which gives rise to dangerously high blood pressure - could lead to new drugs to tackle the condition, which affects up to 7 per cent of pregnancies.
Health experts said the findings could also be used to help find treatments for other blood pressure problems.
Blood pressure is controlled by hormones called angiotensins which constrict blood vessels, but the mechanism behind this process has been a mystery .
Researchers from Cambridge and Nottingham Universities focused their efforts on pre-eclampsia because the condition is characterised by an unusual increase in blood pressure.
They used an extremely intense X-ray beam to probe the structure of the protein angiotensinogen, which releases angiotensin.
The findings, published in the journal Nature, showed that angiotensinogen reacts with oxygen and changes shape to permit access by an enzyme called renin.
By cutting off the protein's "tail", renin triggers the release of the angiotensin hormone, which then raises blood pressure.
Women with pre-eclampsia were found to have more active angiotensinogen than women without the condition.
Drugs currently used to treat high blood pressure, such as ACE (angiotensin converting enzyme) inhibitors, target later stages of the blood pressure process.
The new findings should allow researchers to look for different and possibly more effective treatment strategies for the condition.
Professor Peter Weissberg, medical director of the British Heart Foundation, which helped fund the study, said: "Every year in the UK, pre-eclampsia is responsible for the deaths of around six women and several hundred babies.
"This research is of the highest quality and offers real hope for developing strategies to prevent or treat this dangerous condition by targeting the process that these scientists have identified."
Baby charity Tommy's, which also conducts work into pre-eclampsia, welcomed the findings. Professor Andy Shennan, consultant obstetrician for the charity, said: "This particular work is another step towards determining the mechanisms of pre-eclampsia, to help target the issue. However, there are still many questions regarding its exact cause which we are working to answer."