Low-dose acetylsalicylic acid does not modify maternal vascular reactivity in nulliparas

Objective To assess if the low-dose acetylsalicylic acid (ASA) would be capable of modifying endothelial function throughout pregnancy in nulliparous patients. Methods A double-blind, randomized clinical trial with 277 were included. A total of 139 were orally administered 100 mg/day of ASA, and 138 received placebo. Endothelial function was assessed by flow-mediated dilation (FMD) in the brachial artery before the start of medication (11-14 weeks) and 20-24 and 30-34 weeks of gestation. The intervention was maintained until 34 weeks. The Mann-Whitney U test was used to compare the placebo and ASA groups. The comparison of FMD during pregnancy was performed using the Friedman test. Results The groups (ASA and placebo) were similar regarding to age, weight, height, and body mass index (BMI) (p > .005). The comparison of values of FMD (%) between placebo vs. ASA at 11 and 14 weeks (8.9 vs. 9.7%, p: .253), 20 and 24 weeks (8.8 vs. 10.7%, p: .152), and 30 and 34 weeks (10.7 vs. 9.8%, p: .314) did not show significant changes throughout pregnancy. We observed a significant prevalence of PE in the placebo regarding to ASA group [14 (10.2%) vs. 8 (5.8%), p: .171]. Conclusion Acetylsalicylic acid did not modify the endothelial function assessed by FMD of the brachial artery during pregnancy in nulliparous women.