Extensive study offers ‘definitive proof’ of improved outcomes in high–risk pregnancies.
Taking a low–dose aspirin before bed can reduce the risk of pre–eclampsia, which can cause premature birth and, in extreme cases, maternal and foetal death.

A trial, led by Professor Kypros Nicolaides, Professor of Foetal Medicine at King’s College London, Dr Liona Poon of King’s College London with Professor David Wright of the University of Exeter, found that administering low–dose aspirin (150 mg) led to a 62 per cent reduction in the rate of pre–term preeclampsia, resulting in delivery before 37 weeks.

The study, published in the New England Journal of Medicine, found an 82 per cent reduction in the rate of early preeclampsia, resulting in delivery before 34 weeks.

The double blind, placebo–controlled trail of 1776 women at high risk for pre–term preeclampsia found a lower incidence of developing the disease in women taking aspirin than those taking a placebo. Pre–term preeclampsia occurred in 13 participants (1.6 per cent) in the aspirin group, compared to 35 (4.3 per cent) in the placebo group. The pregnant women were given a dose of 150mg per day from between 11 to 14 weeks of pregnancy up until 36 weeks.

The results prompted calls for low–dose aspirin to be routinely prescribed to women at risk of the disease. The study is the latest in a series of trials which have demonstrated the positive impact of taking low–dose aspirin.

Professor Nicolaides, Director of Harris Birthright Research Centre for Foetal Medicine at King's College London and Chairman of the Foetal Medicine Foundation, said the results of the trial offered ‘definitive proof’ of the effect of aspirin: 'This extensive study is definitive proof that women can take simple measures in the first trimester of pregnancy to significantly reduce their chances of developing pre–term preeclampsia.'

Professor David Wright, Professor of Medical Statistics at the University of Exeter Medical School, said: 'Over the last ten years, we have developed new methods for assessing the risk of pre–eclampsia. We have applied these to identify women for inclusion in the ASPRE trial. The results show that aspirin can prevent preeclampsia in high risk pregnancies. I hope that they will alter clinical practice and improve pregnancy outcomes for mothers and their babies.'

An analysis of more than 30 trials investigating the benefit of a dose of 50 to 150 mg of aspirin per day for the prevention of preeclampsia showed that such therapy resulted in a 10 per cent lower incidence of preeclampsia.

An analysis of individual participant data from the trials, the effect of aspirin was not affected by the stage in the pregnancy it was introduced. But other analyses have shown that aspirin started at or before 16 weeks of gestation resulted in halving the rates of preeclampsia, foetal–growth restriction, and perinatal death, whereas aspirin started after 16 weeks of gestation did not have a significant benefit.

The Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence–Based Pre–eclampsia Prevention (ASPRE) trial was conducted at 13 maternity hospitals in the United Kingdom, Spain, Italy, Belgium, Greece, and Israel. All women who had a routine prenatal visit in the participating hospitals were offered screening for pre–eclampsia combining maternal factors, such as weight, family history, medical history including diabetes, mean arterial pressure, uterine–artery pulsatility index, and maternal serum pregnancy–associated plasma protein A and placental growth factor.