The administration of maternal oxygenation (O2) is a commonly used resuscitation technique for fetuses with category II electronic fetal monitoring (EFM) patterns. In cases of recurrent fetal decelerations, the goal of maternal O2 supplementation is to increase fetal oxygenation. Yet, evidence to support this technique is limited and based on literature published 40 years ago. However, a recent study compared O2 supplementation with room air (RA) in patients with category II EFM patterns and found that RA was not inferior to O2 supplementation. The aim of the current study was to examine the effect of O2 supplementation in patients with category II EMF patterns on pregnancy outcomes. This study was a randomized controlled trial, which assigned patients in active labor and with category II EFM patterns to either 10 L/min of O2 supplementation or RA. Included were patients with normal pregnancies admitted for labor induction or spontaneous delivery, for whom EFM data were available. Excluded were patients with major fetal anomalies, multiple gestations, and maternal hypoxia. Patients with category II EFM patterns requiring intrauterine resuscitation were randomly assigned to either the O2 group or RA group. EFM data were collected 60 minutes before and after randomization. The primary outcome was represented by a composite of high-risk category II features, including recurrent variable, recurrent late, and prolonged decelerations; minimal variability; or tachycardia. Secondary outcomes were the individual components of the primary outcome, total deceleration area, and resolutions of recurrent decelerations. Of the 114 patients included in the analysis, 57 were randomized to the O2 group and 57 to the RA group. The O2 group and RA group had similar rates of the primary outcome (ie, composite of high-risk category II features) within 60 minutes of randomization (42.1% vs 47.4%; relative risk [RR], 0.9; 95% confidence interval [CI], 0.6-1.3). No differences were observed for recurrent variable, recurrent late, and prolonged decelerations in the O2 group versus RA group (P = 0.71, 0.52, and 0.84, respectively), as well as minimal variability (P = 1.00). Tachycardia did not present in either group. In the O2 group, no differences were observed for the primary and secondary outcomes. Likewise, no differences were observed for the primary and secondary outcomes within the RA group. The rates of resolution of recurrent decelerations were similar (75.4% in the O2 group vs 86.0% in the RA group; P = 0.15), as was the total deceleration area (P = 0.22). In this study, maternal O2 supplementation was not observed to improve decelerations, resolve recurrent decelerations, nor hasten recurrent decelerations. The study suggests that O2 administration in cases of high-risk category II EFM patterns may need to be revisited given the lack of benefit and the risks associated with hyperoxygenation.
|Number of pages||3|
|Journal||Obstetrical and Gynecological Survey|
|State||Published - 2021|