A meta-analysis of low-dose aspirin for prevention of preeclampsia

Background : Low-dose aspirin (LDA) is widely used for prevention of preeclampsia. However, conflicting results have been obtained from various studies. Aim: The aim of our study was to evaluate the effect of LDA in prevention of preeclampsia in high-risk and low-risk women.
Materials and Methods : A total of 19 randomized control trials were identified using PUBMED search engine and Cochrane Clinical Trial register. The study population was divided into high-risk and low-risk groups. The effect measured was incidence of preeclampsia in women taking either LDA or placebo where the relative risk (RR) and the 95% confidence interval (CI) were calculated for both groups.
Results : A total of 28237 women were studied, out of which 16550 were in the low-risk group while 11687 were in the high-risk group. The overall incidence of preeclampsia was 7.4%. With the aspirin group it was 6.9% while in the placebo group it was 7.8%. In the high-risk group there was 21% reduction in the risk of preeclampsia associated with the use of aspirin (RR 0.79, 95% CI 0.65-0.97). However, LDA is not effective in reducing the risk in low-risk population (RR 0.86, 95% CI 0.64-1.17).
Conclusion: LDA has a small effect in the prevention of preeclampsia in women considered to be at high risk for the disease. However, it is not effective in reducing the risk in the low-risk group.

Keywords
Intrauterine growth restriction, low-dose aspirin, meta-analysis, preeclampsia