Pre-eclampsia can threaten the life of the mother and her baby, causing very high blood pressure, swelling and kidney damage. It affects more than 50,000 pregnant women a year in Britain. Small studies had suggested that very low dose aspirin might reduce cases by half.
But a study of 9,364 women in 16 countries, reported in tomorrow's Lancet, shows low dose aspirin only reduces the risk of pre-eclampsia by about 25 per cent, with no clear benefit to the baby. The researchers conclude aspirin might still be useful for women who get the symptoms early in pregnancy.