Aspirin dose and its effects during pregnancy

Dose based aspirin pharmacokinetics and pharmacodynamics in pregnancy and association with pregnancy outcomes

NIH-funded research Thomas Jefferson University · NIH-11258547

This trial compares two aspirin dosing schedules in pregnant people at high risk for preeclampsia to see which dose better prevents pregnancy complications.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionThomas Jefferson University NIH-funded
Lab location1 site (Philadelphia, United States)
Project IDNIH-11258547 on NIH RePORTER

What this research studies

If you join, you would be randomly assigned to take either 81 mg twice daily or 162 mg once daily of aspirin starting before 16 weeks and continuing until 36 weeks. The study plans to enroll about 300 people with a single pregnancy who are at high risk for preeclampsia and will check how well aspirin is working at the start, a few weeks after starting, and again in the late second/early third trimester. Blood tests and a platelet function test will be used to measure aspirin response, and a smaller group of about 50 participants will have intensive 8-hour visits in the first and third trimesters to measure aspirin levels over time. The team will compare aspirin response patterns to pregnancy outcomes to learn which dosing may be most protective.

Who could benefit from this research

Good fit: Ideal candidates are adult pregnant people (single pregnancies) judged to be at high risk for preeclampsia who can start aspirin before 16 weeks of gestation.

Not a fit: People with low-risk pregnancies, multiple gestations, known allergy to aspirin, or those who cannot attend in-person visits are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, this work could identify a better aspirin dosing approach that lowers the risk of preeclampsia and preterm birth for high-risk pregnancies.

How similar studies have performed: Previous trials showed that low-dose aspirin can reduce preeclampsia risk, but the best dose and how aspirin works across pregnancy are not well established.

Where this research is happening

Philadelphia, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.