Aspirin Reduced Development of Preeclampsia in Pregnant Patients With and Without Chronic Hypertension

Dispensing aspirin (Bayer) at the first prenatal visit was associated with a reduction in the development of preeclampsia with severe features in patients with and without chronic hypertension, according to authors of research published in Pregnancy. Additionally, the investigators noted that these effects were observed without an increased risk of hemorrhage or abruption.¹

Preeclampsia is a complication of pregnancy. People with preeclampsia may have high blood pressure, high levels of protein in the urine that indicate kidney damage (proteinuria), or other signs of organ damage. Usually, preeclampsia begins after 20 weeks of pregnancy in women whose blood pressure had previously been in the standard range. When left untreated, preeclampsia can lead to serious—and sometimes fatal—complications for the mother and the baby. Often, early delivery of the baby is recommended, but the timing of delivery can depend on how severe preeclampsia is and how many weeks into the pregnancy.²

Before delivery, preeclampsia treatment includes careful monitoring and medications to lower blood pressure and manage complications. At times, preeclampsia may develop after delivery of a baby, a condition known as postpartum preeclampsia.²

For this study, the investigators aimed to evaluate the potential effects of universal aspirin dispensation in a population in which most patients are at moderate or high risk of preeclampsia. This inception cohort study included all deliveries at a public hospital between April 2020 and July 2025. Beginning on August 3, 2022, 162 mg of aspirin was administered once per day to all patients presenting for prenatal care before or at 16 weeks’ gestation. Prior to this period, aspirin was not recommended regardless of participants’ risk factors.¹

Preeclampsia with severe features was a clinical diagnosis with the administration of magnesium sulfate for severe hypertension or lab abnormalities. Analysis exclusion criteria included first prenatal visit at or following 17 weeks’ gestation and all deliveries during the washout period of August 3, 2022, to February 3, 2023.¹

Two cohorts, each comprising 18,457 patients, before and after aspirin implementation, were compared in this study. According to the findings, participants in the aspirin cohort had an approximately 29% lower rate of preeclampsia with severe features (7.12% vs 5.19%, respectively; OR, 0.71; 0.66-0.78; P < .001), and the time to diagnosis was longer (P < .001). Patients with chronic hypertension were less likely to develop preeclampsia (OR, 0.72; 0.60-0.87) as were those in the aspirin cohorts who did not have chronic hypertension (OR, 0.63; 0.57-0.70).¹

Of note, the rate of neonatal intraventricular hemorrhage and gastroschisis and the frequency of placental abruption did not change. The rate of postpartum hemorrhage, defined as blood loss greater than 1000 mL, decreased with aspirin use (9.5% vs 8.9%, respectively; P = .03). Pharmacy data for the aspirin cohort confirmed 14,754 (80.4%) patients with a prenatal visit before or at 16 weeks received aspirin, with a median of about 180 tablets dispensed per patient.¹

“Implementation of directly-dispensed aspirin in this high-risk pregnant population appeared to delay the onset, and for some patients completely prevent the development, of preeclampsia with severe features,” said lead researcher Elaine L. Duryea, MD, associate professor in the Department of Obstetrics and Gynecology at UT Southwestern Medical Center in Dallas and Medical Director of the Maternal-Fetal Medicine Clinic at Parkland Health and Hospital System, said in a news release. “While we cannot be sure that similar effects will be observed in other patient populations, there was no evidence of harm caused by aspirin administration.”³

REFERENCES

1. Duryea EL, Ambia AM, Pruszynski JE, et al. Late-breaking abstract presentations – LB02: universal aspirin administration for prevention of preeclampsia. Pregnancy. 2026;2:e70204. doi:10.1002/pmf2.70204

2. Preeclampsia. Mayo Clinic. April 15, 2022. Accessed February 16, 2026. https://www.mayoclinic.org/diseases-conditions/preeclampsia/symptoms-causes/syc-20355745

3. New study: Routine aspirin therapy prevents severe preeclampsia in at-risk populations. News release. Society for Maternal-Fetal Medicine. February 11, 2026. Accessed February 16, 2026. https://www.eurekalert.org/news-releases/1115004