Persisting risk factors for preeclampsia among high-risk pregnancies already using prophylactic aspirin: a multi-country retrospective investigation.

These findings suggest that individuals with twin pregnancies, a history of preeclampsia, or hypertension may not benefit from aspirin to the same extent as those with other complications such as obesity or diabetes. Careful clinical monitoring for these risks factors is recommended and future research into the effectiveness in these populations would increase our understanding of the current best practice of prophylactic aspirin use to prevent preeclampsia. Current Controlled Trials ISRCTN23781770 and ClinicalTrials.gov NCT01355159.