557 Pregnancy outcomes associated with pragmatic use of aspirin at a single tertiary care center

Abstract

ACOG recommends low-dose aspirin (ASA) for preeclampsia prophylaxis in high-risk women. Randomized trials have also shown decreased preterm birth (PTB) with ASA use. We evaluated rates of PTB, preeclampsia, and other adverse perinatal outcomes associated with pragmatic antepartum ASA use in high-risk women (Table 1). Retrospective cohort study of all deliveries at a single center (2013-2018). Patients with known fetal anomalies were excluded. Women were categorized by documented antepartum use of ASA (irrespective of dose/initiation GA). The primary outcome was any PTB. Other outcomes included preeclampsia, perinatal outcomes, and bleeding parameters. Outcomes were compared between cohorts (ASA vs no ASA); multivariable generalized estimating equations were used to calculate adjusted odds ratios (95% CI) with the no ASA group as the reference. Of 23,602 women who met inclusion criteria, 3069 (13%) had documented ASA use. Women receiving ASA were more likely to be single, Black, obese, multiparous, have medical comorbidities, and use government insurance (all p<0.01). While women in the ASA group had more PTBs in univariate analysis, after multivariable adjustments, they were less likely to have a PTB (aOR 0.63 [0.52-0.77], specifically PTB <34weeks (aOR 0.55 [0.44-0.68]). There was no difference in preeclampsia, placental abruption, fetal or maternal death between groups. Additionally, neonates of women in the ASA group were significantly less likely to be admitted to the NICU (aOR 0.76 [0.60-0.95]) Of note, there was higher EBL with ASA, but there was no increase in uterotonic use, wound morbidity, or blood transfusion in the ASA group (Table 2). Even outside of strict protocols in randomized trials, pragmatic antepartum ASA use is associated with decreased risk of PTB, specifically early PTB, and neonates requiring NICU admission. While there was no reduction in preeclampsia or other rare outcomes, the benefits we confirm in high-risk women should prompt studies in lower-risk women to evaluate if there is a universal benefit to antepartum ASA use.View Large Image Figure ViewerDownload Hi-res image Download (PPT)