A Phase 3 interventional study of 162mg Aspirin and 81mg Aspirin in Preterm Delivery and Obstetrical Complications, sponsored by The George Washington University Biostatistics Center. Recruiting at 14 sites in United States. Open to female participants aged 14 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-09.
Sponsored by The George Washington University Biostatistics Center · Phase 3, Interventional, and Prevention
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Among 742 studies in Premature Birth with a site in United States — 104 open to participants now, 136 under way, 9 of them phase 3. Premature Birth · United States.
Among the 742 studies in Premature Birth with a site in United States, this one is the 21st largest by planned enrollment of the 529 interventional ones that give a count, is one of 23 that started in 2025, is one of 49 in phase 3, reaches primary completion later than 108 of the 135 other live ones, and was the 708th registered.
2,554 studies on the registry are indexed under Premature Birth; 503 are open to participants now.
Browse Premature Birth studies →104 of the 742 studies in Premature Birth with a site in United States are open now. Recruiting first, the newest first:
Duke University · Sites in United States
Ages 0 days–9 mo
University of South Carolina · Sites in United States
Ages 18+ · Women only
Columbia University · Sites in United States
Ages 18–40 · Women only
University of Alabama at Birmingham · Sites in United States
Ages 1 days–3 days
The University of Texas Medical Branch, Galveston · Sites in United States
Ages 18+ · Women only · Healthy volunteers
A study can be open while its sites in United States have not opened yet or have stopped. Only those recruiting at a site in United States →
Of the 315 Premature Birth studies recruiting now, 88 (28%) set no upper age limit and 223 (71%) stop at 75 or younger; 241 take children under 18; 105 take healthy volunteers.
This study: 14 Years and older · female · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
742 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 49 · Phase 2 68 · Phase 3 66 · Phase 4 23
First in 1987; this study’s year is marked. 23 started in 2025.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 1,800 is above the median of 84 across 1,670 interventional studies indexed under Premature Birth.
Median enrollment 85 across the 529 interventional studies, 104 across the 209 observational. Of the 542 that completed or were terminated, 145 (27%) have results posted.
This tab as a report to print or save as PDF → With an account.
74 of 742 have an industry lead sponsor. The 10 most frequent:
The George Washington University Biostatistics Center is the lead sponsor of 25 studies on the registry; 3 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 6 (100%) have results posted.
The George Washington University Biostatistics Center has 9 studies filed under Premature Birth — fewer than ten, so there is no comparison to draw.
46 of the studies in Premature Birth with a site in United States that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT04614714Phase 3University of California, DavisMilk Volume Outcomes Following Oral Nicotinamide Riboside Supplementation in Mothers of Extremely Preterm Infants | 2027-08-30 |
| NCT03797183University of Colorado, DenverGenesis Electrical Impedance Tomography (EIT): A Preliminary Study | 2026-11 |
| NCT04372953Murdoch Childrens Research InstitutePositive End-Expiratory Pressure (PEEP) Levels During Resuscitation of Preterm Infants at Birth (The POLAR Trial). | 2026-11-30 |
| NCT01483079Baylor College of MedicinePost-Discharge Growth of Infants Who Received Donor Human Milk Products in the Neonatal Intensive Care Unit (NICU) | 2026-12 |
| NCT07674953University of ArkansasHow Different Levels of CPAP Affect Oxygen Delivery and Lung Expansion in Preterm Infants | 2026-12 |
Add all 46 to your calendar (.ics) → With an account.
Among the 742 studies in Premature Birth with a site in United States, from their registry updates:
This tab as a report to print or save as PDF → With an account.
This is a phase-III multi-center double-blind randomized clinical trial of 1,800 individuals with a history of prior preterm birth at less than 35 weeks gestation who are randomized to either 162 mg aspirin or 81 mg aspirin daily. The study drug will be initiated between 10 and 15 weeks gestation and continued through 36 weeks, 6 days gestation. The primary endpoint is recurrent preterm delivery or fetal death prior to 35 weeks, 0 days gestation.
This is a phase-III multi-center double-blind randomized clinical trial of 1,800 individuals with a history of prior preterm birth at less than 35 weeks gestation who are randomized to either 162 mg aspirin or 81 mg aspirin daily.
The primary objective is to assess the efficacy of daily 162 mg of aspirin compared to 81 mg aspirin in reducing recurrent preterm delivery or fetal death before 35 weeks, 0 days gestation in individuals with a proximal birth between 20 weeks, 0 days and 34 weeks, 6 days gestation with spontaneous preterm delivery (sPTB), ischemic placental disease (IPD), or stillbirth. Ischemic placental disease includes small for gestational age, preeclampsia, or placental abruption.
The secondary objective is to assess the efficacy of daily 162 mg of aspirin compared to 81 mg aspirin in reducing ischemic placental disease in individuals with a proximal birth between 20 weeks, 0 days and 34 weeks, 6 days gestation with sPTB, IPD, or stillbirth.
Tertiary /Exploratory objectives are 1) to assess the efficacy of daily 162 mg of aspirin compared to 81 mg aspirin in reducing adverse maternal and neonatal outcomes, and 2) to assess maternal and neonatal safety in individuals with a proximal birth between 20 weeks, 0 days and 34 weeks, 6 days gestation with sPTB, IPD, or stillbirth.
Individuals will be randomized between 10 and 15 weeks gestation to either 162mg or 81mg of aspirin daily and continue the study intervention through 36 weeks, 6 days gestation. Participants will have monthly virtual or in-person visits through 37 weeks gestation to assess study intervention compliance, side effects, medication use, and unscheduled hospitalization. Maternal blood will be collected in a subset of the population. Research staff will abstract maternal and neonatal outcomes following delivery and discharge from the hospital.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Prior preterm birth between 20 weeks 0 days and 34 weeks 6 days with one of the following in the proximal birth reaching 20 weeks or greater:
Exclusion Criteria:
Patients with any of the following medical conditions because of increased risk for adverse pregnancy outcome or indicated preterm birth:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
One 81mg capsule of aspirin daily through 36 weeks 6 days gestation.
Drug: 162mg Aspirin
Two 81mg capsules of aspirin daily through 36 weeks 6 days gestation.
Drug: 81mg Aspirin
Two 81mg aspirin tablets in an over-encapsulated capsule filled with microcrystalline cellulose. Study intervention will be packaged into bottles (35 capsules per bottle).
One 81mg aspirin tablet in an over-encapsulated capsule filled with microcrystalline cellulose. Study intervention will be packaged into bottles (35 capsules per bottle).
Rate of recurrent preterm delivery or fetal death prior to 35 weeks 0 days gestation
Number and rate of participants who experience a recurrent preterm delivery or fetal death before 35 weeks, 0 days gestation.
Time frame: Between randomization and 35 weeks, 0 days gestation (a period of up to 25 weeks)
Rate of ischemic placental disease
Number and rate of participants who experience ischemic placental disease (preeclampsia, small for gestational age \<10th percentile, or placental abruption). Small for gestational age is defined by "A 2017 US reference for singleton birth weight percentiles using obstetric estimates of gestation" by Aris et. al (2019).
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of recurrent preterm delivery or fetal death at <28 weeks
Number and rate of participants who experience a recurrent preterm delivery or fetal death at less than 28 weeks
Time frame: Between randomization and delivery (a period of up to 18 weeks)
Rate of recurrent preterm delivery or fetal death at <37 weeks
Number and rate of participants who experience a recurrent preterm delivery or fetal death at less than 37 weeks
Time frame: Between randomization and delivery (a period of up to 27 weeks)
Rate of ischemic placental disease with delivery prior to 28 weeks
Number and rate of participants who experience ischemic placental disease (preeclampsia, fetal growth restriction, or placental abruption) with delivery before 28 weeks gestation
Time frame: Between randomization and delivery (a period of up to 18 weeks)
Rate of ischemic placental disease with delivery prior to 35 weeks
Number and rate of participants who experience ischemic placental disease (preeclampsia, fetal growth restriction, or placental abruption) with delivery before 35 weeks gestation
Time frame: Between randomization and delivery (a period of up to 25 weeks)
Rate of Ischemic Placental Disease with Delivery Prior to 37 weeks
Number of participants who experience ischemic placental disease (preeclampsia, fetal growth restriction, or placental abruption) with delivery before 37 weeks gestation
Time frame: Between randomization and delivery (a period of up to 27 weeks)
Rate of preeclampsia
Number and rate of participants who experience preeclampsia
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of preeclampsia with severe features
Number and rate of participants who experience preeclampsia with severe features including HELLP syndrome and eclampsia
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of placental abruption
Number and rate of participants who experience placental abruption as defined clinically (not pathologically determined)
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Number of emergency room visits or hospitalizations
Mean or median number of non-scheduled emergency room visits or hospitalizations
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Number of days between randomization and delivery or fetal death
Mean or median number of days between randomization and delivery or fetal death
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of stillbirth
Number and rate of stillbirths defined as fetal deaths occurring on or after 20 weeks, 0 days gestation
Time frame: Between 20 weeks gestation and delivery (a period of up to 22 weeks)
Rate of small for gestational age at less than 5th percentile
Number and rate of neonates determined to be small for gestational age at less than the 5th percentile. Small for gestational age is defined by "A 2017 US reference for singleton birth weight percentiles using obstetric estimates of gestation" by Aris et. al (2019).
Time frame: At delivery
Rate of small for gestational age at less than 10th Percentile
Number of neonates determined to be small for gestational age at less than the 10th percentile. Small for gestational age is defined by "A 2017 US reference for singleton birth weight percentiles using obstetric estimates of gestation" by Aris et. al (2019).
Time frame: At delivery
Rate of neonatal death
Number and rate of neonatal deaths
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of neonatal intensive care unit (NICU) admission
Number and rate of neonates admitted to the neonatal intensive care unit (NICU)
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Neonatal Length of Hospital Stay
Mean or median number of days neonates stayed hospitalized
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of neonatal ventilator or continuous positive airway pressure (CPAP use
Number and rate of neonates who needed ventilator or continuous positive airway pressure (CPAP) use
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of neonatal oxygen use
Number and rate of neonates who used oxygen for at least 4 continuous hours in the first 72 hours from birth
Time frame: Between delivery and 72 hours post birth
Rate of neonatal seizure
Number and rate of neonates who experienced seizures requiring treatment
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of neonatal hyperbilirubinemia
Number and rate of neonates who experienced hyperbilirubinemia requiring treatment
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of neonatal infectious morbidity
Number and rate of neonates who experienced neonatal infectious morbidity defined as any one of the following: suspected sepsis, early onset sepsis, late onset sepsis, or pneumonia
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of perinatal composite outcome
Number and rate of neonates with the perinatal composite outcome defined as any of the following: * Fetal or neonatal death * Bronchopulmonary dysplasia (BPD) grade 3 or higher * Intraventricular hemorrhage (IVH) grades 3 or 4 * Necrotizing enterocolitis (NEC) proven - Bell Stage 2A or greater * Periventricular leukomalacia (PVL) * Retinopathy of prematurity (ROP) stage III-V * Proven sepsis (early or late)
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of minor bleeding
Number and rate of participants who reported minor bleeding defined as any of the following: vaginal spotting, gum, or nasal bleeding not requiring surgical coagulation/ packing.
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of thrombocytopenia
Number and rate of participants with thrombocytopenia defined as a platelet count \< 100k
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of aspirin allergy
Number and rate of participants that report an allergic reaction to aspirin
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of gastric ulcer disease
Number and rate of participants that report active gastric ulcer disease that is not responsive to common therapies
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of persistent epistaxis
Number and rate of participants that report persistent epistaxis (nosebleeds) defined as prolonged nosebleeds that last for more than 15 minutes or occur more than once a week, or require medical intervention.
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of clinically meaningful bleeding
Number and rate of participants that report clinically meaningful bleeding defined as any of the following: abruption, hemoptysis (coughing up blood or bloody mucus), nasal bleeding requiring coagulation or packing
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Estimated blood loss
Mean or median estimated blood loss during delivery
Time frame: Delivery
Rate of estimated blood loss greater than 1000ml
Number and rate of participants that have an estimated blood loss during delivery greater than 1000ml
Time frame: Delivery
Rate of transfusion of packed red blood cells
Number and rate of participants that have a transfusion of packed red blood cells
Time frame: Between delivery admission and hospital discharge (a period of up to 120 days)
Rate of cesarean hysterectomy
Number and rate of participants who had a cesarean hysterectomy
Time frame: Delivery
Rate of intensive care unit (ICU) admission
Number and rate of participants admitted to the intensive care unit (ICU)
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of intracranial hemorrhage
Number and rate of participants who experienced an intracranial hemorrhage
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of congenital malformation
Number and rate of congenital malformation and premature narrowing or closure of the ductus arteriosus
Time frame: Between randomization and hospital discharge (a period of up to 49 weeks)
Rate of oligohydramnios
Number and rate of participants with clinically-defined oligohydramnios
Time frame: Between randomization and delivery (a period of up to 32 weeks)
Rate of neonatal primary pulmonary hypertension
Number and rate of neonates with primary pulmonary hypertension
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Rate of neonatal intracranial hemorrhage
Number and rate of neonates with perinatal intracranial hemorrhage
Time frame: Between delivery and hospital discharge (a period of up to 120 days)
Plan to share: Yes — Data will be shared via NICHD DASH in accordance with NIH policy.
Supporting information: Study protocol, Informed consent form
No publications or documents are linked to this record.
Started Jul 2025 (actual). Primary completion is estimated for Dec 2028, 41 months after the start.
Of 35 non-industry phase 3 interventional studies under Premature Birth, half reached primary completion within 53 months of starting (the median), counting those still running; a quarter within 28 and three quarters within 89. This study's planned 41 months is below that.
Counting every sponsor, half of 40 studies reached it within 51 months; a quarter within 28 and three quarters within 89.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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Studies of the drug tested here: Aspirin
The George Washington University Biostatistics Center