Implementation of a universal low-dose aspirin protocol for the prevention of preeclampsia in a federally qualified health center.

Objectives: Low-dose aspirin (LDA) prophylaxis is an evidence-based intervention that reduces preeclampsia risk, yet adherence remains suboptimal in underserved populations due to inconsistent risk assessment and communication gaps. This study evaluated the impact of a universal LDA protocol at a Federally Qualified Health Center (FQHC) serving a socially vulnerable population.

Methods: Patients initiating prenatal care between 12 and 28 weeks of gestation were included. A retrospective cohort from 2021 (pre-intervention) was compared to a prospective cohort from 2022 (post-intervention). The intervention prescribed daily LDA to all eligible patients. Adherence was defined as provider-documented patient use during at least one follow-up visit and at delivery, an indirect measure relying on patient report and provider documentation. The primary outcome was LDA adherence. Secondary outcomes included preeclampsia with and without severe features and postpartum hemorrhage requiring blood transfusion. Multivariable logistic regression adjusted for maternal age, pregestational diabetes, and chronic hypertension.

Results: Among 775 patients, LDA adherence increased from 8.7 % pre-intervention to 75.0 % post-intervention (p<0.001). The incidence of preeclampsia with severe features decreased significantly (OR 0.14, 95 % CI 0.04-0.37). In high-risk patients, adherence rose from 8.9 to 70.9 % (p<0.001) with a similar reduction in severe preeclampsia (OR 0.16, 95 % CI 0.05-0.44). No significant changes were observed in preeclampsia without severe features or postpartum hemorrhage requiring transfusion.

Conclusions: Implementation of a universal LDA protocol in a high-risk, underserved population markedly improved adherence and reduced severe preeclampsia without increasing hemorrhage risk, offering a practical, low-cost strategy to improve maternal outcomes.