39 - Effectiveness of Maternal Oxygen Supplementation for Intrauterine Fetal Resuscitation: A Hospital-Based Retrospective Study

Routine maternal oxygen supplementation for category 2 intrapartum fetal heart rate tracings has not been shown to reduce fetal acidemia in prospective studies. We aim to validate that de-implementing this intervention did not increase the risk of neonatal acidemia in a real-world setting.


Study Design:

This is a retrospective, single-institution study of laboring patients with category 2 intrapartum tracings from January 2019 – June 30, 2021. In March 2020, secondary to the COVID pandemic, routine maternal oxygen supplementation for such tracings was abandoned per hospital guidelines, providing the opportunity to compare pre- and post-de-implementation cohorts. Laboring patients with singleton or twin pregnancies between 23-42 weeks of gestational age with persistent category 2 tracings, as identified by a previously described external safety monitoring system, were evaluated. Major fetal anomalies, contraindications to labor and maternal indication for O₂ supplementation were excluded. The primary outcome was fetal acidemia, defined as umbilical cord pH < 7.2. Secondary outcomes included severe acidemia (pH < 7.0), 5-minute Apgar score < 4 and neonatal intensive care unit admission. Regression analyses controlling for known variables associated with neonatal acidemia generated adjusted odds ratios. 

 

Results:

Out of the 9088 deliveries during the study period, 1162 tracings were flagged as category 2, including 681 (59%) in the post-intervention group. The two cohorts had comparable baseline characteristics (Table 1). No difference in neonatal acidemia was observed between the pre- and post-de-implementation group (15.4% vs 13.8%, aOR 0.89, 95% CI 0.63-1.22, Table 2). Severe acidemia, 5-minute Apgar < 4 and NICU admission were not increased in the post-de-implementation group.



Conclusion:

De-implementation of routine maternal oxygen supplementation for category 2 intrapartum fetal tracings did not increase risk for neonatal acidemia in a real-world setting, validating the lack of effectiveness for the intervention.