Rivaroxaban in breast milk after maternal dosing

Excretion of Rivaroxaban in Human Breast Milk

Phase 1 Interventional Thomas Jefferson University · NCT06831474

This will test how much rivaroxaban passes into breast milk in postpartum people taking either prophylactic (10 mg) or therapeutic (20 mg) doses.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment10 (estimated)
Ages18 Years and up
SexFemale
SponsorThomas Jefferson University Academic / other
Locations1 site (Philadelphia, Pennsylvania)
Trial IDNCT06831474 on ClinicalTrials.gov

What this trial studies

This is a phase 1, single-arm trial to measure rivaroxaban concentrations in human milk after single and repeated maternal dosing at prophylactic and therapeutic levels. Participants will take oral rivaroxaban and provide serial breast milk and blood samples over time to calculate milk-to-plasma ratios and estimate relative infant dose. The trial includes postpartum people who are breastfeeding term healthy infants as well as non-breastfeeding participants meeting anticoagulation criteria. Results are intended to expand limited existing data and inform clinician counseling and guideline recommendations for postpartum anticoagulation.

Who should consider this trial

Good fit: Postpartum people within six weeks of delivery, age 18 or older, hemodynamically stable, and either breastfeeding a term healthy infant or meeting criteria for prophylactic or therapeutic rivaroxaban dosing are ideal candidates.

Not a fit: People who are pregnant, under 18, hemodynamically unstable, or caring for preterm or medically unstable infants may not receive benefit from this study's findings.

Why it matters

Potential benefit: If successful, the results could give clinicians clear safety data to better counsel breastfeeding patients and help update postpartum anticoagulation guidelines.

How similar studies have performed: Existing reports on rivaroxaban in breast milk are limited but generally favorable, and this trial expands those sparse positive data by measuring both prophylactic and therapeutic dosing over time.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Postpartum within 6 weeks of delivery
2. Greater than 18 years old at expected date of delivery
3. English speaking
4. Hemodynamically stable without concern for ongoing blood loss
5. Non-breastfeeding
6. Or breastfeeding an infant born at or equal to 37 weeks' gestation, weighing \>2600g at birth and is not requiring intensive care
7. Meet inclusion criteria for prophylactic rivaroxaban dose: pre-pregnancy BMI \>/= 40 and/or any personal history of VTE. Or \>/= 2 of the following: pre-pregnancy BMI 30-39, immobility, pregnancy complications, cesarean delivery, hysterectomy
8. Or meet inclusion criteria for therapeutic rivaroxaban dose: have an indication for therapeutic anticoagulation per the American College of Obstetricians and Gynecologists' (ACOG) practice bulletin #196, or other indication per their primary team, and recommended for such anticoagulation per their primary practitioner.

Exclusion Criteria:

1. Pregnant
2. Less than 18 years old at estimated date of delivery
3. Hemodynamic instability and/or concern for ongoing blood loss
4. Newly diagnosed deep vein thrombosis (DVT) or pulmonary embolism (PE) in the postpartum period
5. Abnormal maternal renal or liver function (creatinine clearance \< 30 mL/min and/or liver function tests greater than lab normal)
6. A contraindication to rivaroxaban: hypersensitivity to rivaroxaban; active pathological bleeding
7. Breastfeeding an infant admitted to neonatal intensive care unit, infant gestational age at birth \<37w0d or weighing \<2600g.
8. If all of the following are met: age less than 40, ambulating, body mass index (BMI) less than 30, no active history of malignancy.
9. If patient lacks indication for therapeutic anticoagulation in the postpartum period per the American College of Obstetricians and Gynecologists' (ACOG) practice bulletin #196

Where this trial is running

Philadelphia, Pennsylvania

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions PostpartumVTE ProphylaxisVTERivaroxabanBreastfeedingBreast Milk CollectionRelative infant doseLACT
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.