Daily versus split-dose aspirin in high-risk pregnancies
Official title: Dose Based Aspirin Pharmacokinetics and Pharmacodynamics in Pregnancy and Association With Pregnancy Outcomes
Run by Thomas Jefferson University · NCT06826859 · Data updated 2026-11-12
This test compares taking aspirin 162 mg once daily versus 81 mg twice daily to see which dosing better prevents preeclampsia and preterm birth in people with high-risk singleton pregnancies who start aspirin before 16 weeks.
Quick facts
| Phase | Phase1; Phase2 |
|---|---|
| Study type | Interventional |
| Ages | 16 Years to 55 Years |
| Sex | Women only |
| Enrollment | 400 (estimated) |
| Sponsor | Thomas Jefferson University Academic / other |
| Locations | 1 site (Philadelphia, Pennsylvania) |
| Status | Recruiting |
| Started | June 26, 2025 |
| Main results expected | July 1, 2029 |
| Study ends | December 31, 2029 |
| Registry record updated | July 17, 2025 |
| Trial ID | NCT06826859 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are people aged 16–55 with a singleton gestation under 16 weeks who meet USPSTF criteria for high preeclampsia risk and have been recommended to take 162 mg aspirin.
✕Probably not a fit
Patients with aspirin contraindications, current or planned anticoagulation, known bleeding or platelet disorders, multiple gestation, or abnormal baseline platelet function are unlikely to be eligible or to receive benefit from this dosing comparison.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This unblinded, randomized Phase I/II trial enrolls people with a singleton pregnancy before 16 weeks who are recommended aspirin for preeclampsia prevention and randomizes them to 162 mg once daily or 81 mg twice daily. The primary outcome is platelet inhibition measured by PFA-100 epinephrine closure time at 2–4 weeks after initiation and again at 28–32 weeks, and a subset will join a pharmacokinetic sub-study to measure aspirin levels at the two dosing schedules. Secondary outcomes include urine thromboxane, platelet-associated microRNAs, and analysis of how individual factors affect aspirin pharmacokinetics and pharmacodynamics in pregnancy. Investigators will relate these pharmacologic markers to clinical pregnancy outcomes including preeclampsia and preterm birth.
Why it matters
Potential benefit: If successful, this could identify an inexpensive, practical aspirin dosing approach that reduces preeclampsia and preterm birth in high-risk pregnancies.
How similar studies have gone: Low-dose aspirin has been shown to reduce preeclampsia risk in high-risk pregnancies, but split-dose regimens and detailed pregnancy-specific pharmacokinetic data are novel and have limited prior evidence.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria * Singleton gestation gestational age \<16 0/7 weeks, dating confirmed with ultrasound * ≥1 high risk factor for preeclampsia or ≥2 moderate risk factors as per United States Preventative Services Task Force (2021) * Recommendation for 162mg aspirin daily in pregnancy * Age 16-55 years old Exclusion criteria * Contraindication to aspirin * Current or planned use of any other anticoagulation * Thrombocytopenia, other known platelet or bleeding disorder * Abnormally elevated baseline PFA-100 epinephrine closure time prior to aspirin initiation
Where it's running
-
Thomas Jefferson University
Philadelphia, Pennsylvania, United States Recruiting
Study contacts
- Study coordinator: Rupsa C Boelig, MD
- Email: rupsa.boelig@jefferson.edu
- Phone: 215-955-5000
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.