The objective of this research project is to conduct a single-site pilot trial to assess the feasibility and effect of low-dose aspirin to augment vascular recovery in the immediate postpartum period after preeclampsia through two specific aims: 1) to pilot test the feasibility of conducting a randomized controlled trial of postpartum low dose aspirin vs. placebo, and 2) to assess the effect of postpartum aspirin on endothelial function and blood pressure. Our central hypothesis is that postpartum administration of low-dose aspirin following preeclampsia will be feasible, improve endothelial function, and lower BP at 6 months postpartum. Subjects will undergo 3 study visits involving BP measurements, blood draws, questionnaires, and/or microiontophoresis. Up to 60 adult subjects will be enrolled at Magee-Women's Hospital.