Aspirin in pregnancy: a review of indications, timing, dosing and efficacy

The aim of this study was to evaluate the recent literature examining the utility of low-dose daily aspirin (LDA) in the prevention of preeclampsia and other potential adverse perinatal sequelae. The evidence supporting various aspirin doses and timing of initiation of treatment for this purpose will be examined. The potential benefits of LDA therapy in pregnancy will be discussed weighing against any potential associated harm.

Findings from several recent meta-analyses of randomized controlled trials are consistent with prior studies in showing a reduction in risk for preeclampsia with LDA use in individuals at an increased risk for this complication. Some studies suggest aspirin at a dose greater than the current recommended 81 mg is associated with the highest reduction in preterm PE.Several studies have demonstrated a reduction in risk for preterm birth, small for gestational age (SGA) infant or intrauterine growth restriction (IUGR), and a reduction in the risk of perinatal mortality associated with aspirin use. The findings of reduced preterm birth (PTB) and IUGR were also demonstrated among low-risk patients.Identifying patients at risk was re-evaluated, with resulting changes to existing United States Preventive Services Task Force (USPSTF) guidelines.

This review of recent evidence suggests a decreased rate of preeclampsia at aspirin doses higher than the standardly used 81 mg when treatment is initiated prior to 16 weeks of gestation. Although LDA use seems promising for other outcomes such as preterm delivery and IUGR, further studies to strengthen recommendations are warranted.