Aspirin Prophylaxis

Preeclampsia is a leading cause of maternal morbidity and mortality. Low-dose aspirin prophylaxis reduces preeclampsia risk among high-risk pregnant individuals but remains underused in routine clinical practice. This pragmatic cluster-randomized implementation trial will test whether clinician notification of elevated preeclampsia risk increases aspirin prophylaxis utilization among eligible pregnant individuals receiving outpatient obstetric care. Clusters will be randomized to clinician notification versus usual care. In the intervention arm, obstetric clinicians will receive notification that a patient is at elevated risk for preeclampsia and a recommendation to consider initiation of aspirin prophylaxis between 12 and 28 weeks' gestation, as clinically appropriate. The intervention does not assign participants to aspirin and does not require any study-mandated medication. All decisions regarding aspirin prophylaxis will remain at the discretion of the treating obstetric clinician and patient.