The association between postpartum aspirin use and NT-proBNP levels as a marker for maternal cardiac health: a randomized controlled trial.

BACKGROUND: During pregnancy, administration of low-dose aspirin 81 mg (LDA) has been demonstrated to decrease the incidence of preeclampsia in at-risk individuals. However, the role of continuation of LDA in the postpartum period and its association with long-term maternal health outcomes is unknown. OBJECTIVE: This study aimed to compare levels of NT-proBNP (N-terminal pro-B-type natriuretic peptide), a marker of cardiac strain, and clinical outcomes between patients at risk of preeclampsia randomly assigned to continuation of low-dose aspirin and those who received placebo for 6 weeks postpartum. STUDY DESIGN: This double-blinded randomized controlled trial included patients at risk of preeclampsia randomly assigned in a 1:1 ratio to low-dose aspirin (81 mg) or placebo for 6 weeks postpartum. The primary outcome was NT-proBNP levels at the postpartum visit. A sample size of 90 was required to detect a clinically significant difference in NT-proBNP between low-dose aspirin and placebo with 80% power. A sample size of 110 participants was planned because of anticipated loss to follow-up in the postpartum period. Prespecified secondary outcomes were postpartum preeclampsia, eclampsia, hospital readmission, initiation or titration of blood pressure medications, and blood transfusion. The primary outcome was compared using the Wilcoxon rank sum test. Secondary outcomes are reported as count (percentage) and were compared using the Fisher exact test after adjusting for multiple testing using Bonferroni correction. RESULTS: From July 2023 to May 2024, 110 participants were randomly assigned to low-dose aspirin (n=55) or placebo (n=55). Baseline demographics were similar between groups. There was no difference in the primary outcome of NT-proBNP levels between groups (median [interquartile range], 36.5 [36.0-61.0] vs 39.5 [36.0-74.0] ng/mL; P=.49). Rates of postpartum preeclampsia among patients randomly assigned to low-dose aspirin vs placebo (5.6% vs 12.7%; P=.32) were numerically but not statistically significantly lower, with similar rates of hospital readmission and bleeding complications. There were no cases of postpartum eclampsia or blood transfusion. CONCLUSION: Continuation of low-dose aspirin after delivery was not associated with decreased NT-proBNP levels compared with placebo. Additional studies powered to detect differences in maternal outcomes are needed to evaluate the role of low-dose aspirin in the postpartum period.

Duke Scholars

Author Alaattin Erkanli Biostatistics & Bioinformatics, Division of Biostatistics

Author Jerome Jeffrey Federspiel Obstetrics and Gynecology, Maternal Fetal Medicine

Author Sarahn M Wheeler Obstetrics and Gynecology, Maternal Fetal Medicine

Author Brenna L Hughes Obstetrics and Gynecology, Maternal Fetal Medicine

Author Shakthi Unnithan  

Author Anthony Emyll Melendez Torres Obstetrics and Gynecology, Maternal Fetal Medicine