# Maternal oxygen supplementation for Intrauterine Resuscitation: a Multicenter Randomized Trial

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2022 · $709,350

## Abstract

Abstract
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. The goal of such monitoring is to identify fetal
hypoxia and prevent the transition to acidemia, expedited operative delivery, and/or neonatal morbidity.
Category II EFM, the most commonly observed group of fetal heart rate features, is associated with variable
risks for acidemia. 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, thereby reversing
hypoxia and preventing acidemia. This practice is so commonly used that 2 out of 3 patients receive
supplemental O2 at some point during labor. However, despite the theoretic rationale, there is no rigorous data
to support its widespread use. Our pilot randomized noninferiority trial, published in JAMA Pediatrics,
demonstrated that room air was noninferior to O2 for improving umbilical artery lactate, a surrogate marker of
fetal acidemia and neonatal morbidity. Our subsequent meta-analysis of randomized trials investigating O2
versus room air at time of cesarean section or vaginal delivery found no differences in umbilical artery pH,
rates of acidemia, and neonatal intensive care unit admissions between room air and O2 groups. Importantly,
none of the trials studied important clinical measures of neonatal or maternal morbidity and only one trial
studied O2 in the setting of Category II EFM. The current state of evidence is limited in several ways. First, the
existing studies of O2 in labor vary in the dose, duration, and timing of O2 administration. Second, only one
pilot trial investigated the utility of O2 supplementation for the ACOG-recommended indication of Category II
EFM. Third, all of the studies have used surrogate measures of neonatal morbidity such as cord gases or
neonatal intensive care unit admission. Finally, none of the studies were powered to assess the impact of O2
administration on neonatal clinical sequelae of in utero hypoxia or operative delivery. Without data on these
definitive outcomes, evidence-based recommendations for managing Category II EFM cannot be made.
To fill this important knowledge gap, we propose a large, multicenter, randomized noninferiority trial of O2
supplementation versus room air in patients with Category II EFM in labor. Our central hypothesis is that
clinically relevant maternal and neonatal outcomes will not significantly differ between the two arms. We
will pursue the following specific aims: 1) Determine the effect of room air, compared with supplemental O2,
on neonatal morbidity among patients with Category II EFM and 2) Determine the effect of room air,
compared with supplemental O2, on rates of operative delivery. A total of 2124 patients will be randomized
to provide adequate power to detect clinically meaningful noninferiority margins for the above stated
outc...

## Key facts

- **NIH application ID:** 10422948
- **Project number:** 1R01HD108614-01
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Nandini Raghuraman
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $709,350
- **Award type:** 1
- **Project period:** 2022-09-16 → 2027-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10422948

## Citation

> US National Institutes of Health, RePORTER application 10422948, Maternal oxygen supplementation for Intrauterine Resuscitation: a Multicenter Randomized Trial (1R01HD108614-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10422948. Licensed CC0.

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