NCT05681624 · Washington University School of Medicine
Maternal Oxygen Supplementation for Intrauterine Resuscitation
(MOXY)
What this study is about
More than 80% of the 3 million women who labor and deliver each year in the United States undergo continuous electronic fetal monitoring (EFM) during labor in order to fetal hypoxia and prevent the transition to acidemia, expedited operative delivery, and/or neonatal morbidity. Category II EFM is the most commonly observed group of fetal heart rate features in labor.
View original scientific description
More than 80% of the 3 million women who labor and deliver each year in the United States undergo continuous electronic fetal monitoring (EFM) during labor in order to fetal hypoxia and prevent the transition to acidemia, expedited operative delivery, and/or neonatal morbidity. Category II EFM is the most commonly observed group of fetal heart rate features in labor. One common response to Category II EFM is maternal oxygen (O2) supplementation. The theoretic rationale for O2 administration is that it increases O2 transfer to a hypoxic fetus. There are conflicting national guidelines regarding O2 administration - the American College of Obstetricians and Gynecologists suggest O2 is ineffective, whereas the Association of Women's Health, Obstetric, and Neonatal Nurses recommend continued use given lack of definitive data on safety and efficacy. A recent national survey of nearly 600 Labor \& Delivery providers in February 2022 revealed that 49% still use O2 . Thus, there remains equipoise on the topic and high-quality data on the safety of intrapartum O2 is needed. None of the trials to date have studied the effect of intrapartum O2 on important clinical measures of neonatal or maternal morbidity. This safety data is imperative because the field of obstetrics must hold supplemental O2 to the same rigorous standards applied to any drug used in pregnancy. Without data on these definitive outcomes, it will be challenging to implement evidence-based recommendations for supplemental O2 use on Labor \& Delivery. The investigators will conduct a large, multicenter, randomized noninferiority trial of O2 supplementation versus room air in patients with Category II EFM in labor.
Interventions
OTHER
Maternal oxygen supplementation
Maternal oxygen supplementation 10 liters/minute via nonrebreather mask
OTHER
Room air
Room air, no mask
Primary outcome measures
Percentage of neonates meeting criteria for composite neonatal morbidity
Time frame: Up to 28 days of life
One of the following diagnoses: Neonatal death, acidemia, meconium aspiration with pulmonary hypertension, hypoglycemia, hypoxic ischemic encephalopathy ,hypothermia treatment, seizure, respiratory distress
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Singleton gestation
- Gestational age\>=37 weeks
- Spontaneous labor or induction of labor
- English or spanish speaking
- Planned continuous fetal monitoring
Exclusion criteria
- Preterm gestation
- Major fetal anomaly
- Multiple gestation
- Category III fetal monitoring at time of admission
- Maternal hypoxia \<95%
- Planned or scheduled cesarean delivery Excluded from randomization if receiving nitrous oxide for analgesia at time of randomization.
Where
- St Louis, Missouri
Collaborators
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), University of Michigan, University of Texas at Austin, Women and Infants Hospital of Rhode Island, Dell Children's Medical Center of Central Texas, Brown University
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Data: ClinicalTrials.gov · synced Feb 27, 2026 · Source of record for eligibility and locations