The effect of intrapartum O2 supplementation on category II fetal monitoring

Nandini Raghuraman, Julia D. López, Ebony B. Carter, Molly J. Stout, George Macones, Methodius G. Tuuli, Alison Cahill

Research output: Contribution to journalArticle

Abstract

Background: Maternal O2 administration is a widely used intrauterine resuscitation technique for fetuses with category II electronic fetal monitoring patterns, despite a paucity of evidence on its ability to improve electronic fetal monitoring patterns. Objective: This study investigated the effect of intrapartum O2 administration on Category II electronic fetal monitoring patterns. Study Design: This is a secondary analysis of a randomized trial conducted in 2016–2017, in which patients with fetuses at ≥37 weeks’ gestation in active labor with category II electronic fetal monitoring patterns were assigned to 10 L/min of O2 by face mask or room air until delivery. Trained obstetrical research nurses blinded to allocation extracted electronic fetal monitoring data. The primary outcome was a composite of high-risk category II features including recurrent variable decelerations, recurrent late decelerations, prolonged decelerations, tachycardia, or minimal variability 60 minutes after randomization to room air or O2. Secondary outcomes included individual components of the composite high-risk category II features, resolution of recurrent decelerations within 60 minutes of randomization, and total deceleration area. The outcomes between the room air and O2 groups were compared using univariable statistics. Time-to-event analysis was used to compare time to resolution of recurrent decelerations between the groups. Paired analysis was used to compare the pre- and postrandomization outcomes within each group. Results: All 114 randomized patients (57 room air and 57 O2) were included in this analysis. There was no difference in resolution of recurrent decelerations within 60 minutes between the O2 and room air groups (75.4% vs 86.0%; P=.15). The room air and O2 groups had similar rates of composite high-risk category II features including recurrent variable decelerations, recurrent late decelerations, prolonged decelerations, tachycardia, and minimal variability 60 minutes after randomization. Time to resolution of recurrent decelerations and total deceleration area were similar between the room air and O2 groups. Among patients who received O2, there was no difference in the electronic fetal monitoring patterns pre- and postrandomization. Similar findings were observed in the electronic fetal monitoring patterns pre- and postrandomization in room air patients. Conclusion: Intrapartum maternal O2 administration for category II electronic fetal monitoring patterns did not resolve high-risk category II features or hasten the resolution of recurrent decelerations. These results suggest that O2 administration has no impact on improving category II electronic fetal monitoring patterns.

Original languageEnglish
JournalAmerican journal of obstetrics and gynecology
DOIs
StateAccepted/In press - 2020

Keywords

  • decelerations
  • fetal monitoring
  • intrauterine resuscitation

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