Early prediction and aspirin for prevention of pre-eclampsia (EPAPP) study: a randomized controlled trial

To estimate the effect of early administration of aspirin on the prevention of pre-eclampsia in high-risk women.

This was planned as a randomized, double-blind, placebo-controlled trial of aspirin for women with risk factors for pre-eclampsia. Participants were randomized to start either aspirin (81 mg/day) or placebo at 11 + 0 to 13 + 6 weeks of gestation. The primary outcome was pre-eclampsia and secondary outcomes included gestational hypertension and small-for-gestational age at birth.

The trial suffered from slow recruitment, leading to a protocol change to broaden the inclusion criteria (from a minimum score of multiple risk factors to at least one risk factor for pre-eclampsia). The trial was then terminated prematurely due to continuing slow recruitment and a lack of equipoise given a change in national guidelines to administer aspirin to high-risk women. From the 53 women who were randomized, 30 were included in the final analysis. There was no evidence that the primary outcome of pre-eclampsia was prevented by low-dose aspirin (relative risk (RR) 0.88, 95% CI 0.21-3.66). Gestational hypertension was seen in two women, both in the aspirin group. There was no evidence that the occurrence of small-for-gestational age was reduced by aspirin (RR 0.88, 95% CI 0.06-12.72).

Although this study was underpowered to show effectiveness of aspirin compared to placebo due to the premature termination and difficulties encountered, it highlights practical issues to inform future studies.