Comparing Clark’s 2017 Category II Electronic Fetal Monitoring Algorithm to Actual Management When Umbilical Cord Arterial pH Was Less Than 7 [ID 2683452

Abstract

INTRODUCTION: Our previously published study reported that, in only 47% of labors resulting in a baby with severe acidemia (defined as umbilical cord arterial pH less than 7), intrapartum electronic fetal monitoring (EFM) was interpreted as concerning, with delivery expedited. We compared Clark’s EFM Category II algorithm to EFM interpretation and actual management of these deliveries. METHODS: Institutional review board approval was obtained. A retrospective cohort study was performed on deliveries with umbilical cord arterial pH less than 7. Two groups were identified in actual management: 1) expedited delivery (urgent/emergent operative vaginal delivery or cesarean section) and 2) nonexpedited delivery. We then reviewed all fetal heart tracings (FHTs) to determine whether the algorithm would have recommended expedited delivery or not. Data were analyzed using chi-squared test for independence and Fisher's exact test. RESULTS: Thirty deliveries were identified with severe fetal acidemia. Forty-seven percent were delivered in expedited fashion. The Clark algorithm recommended expedited delivery in 30%. The algorithm was not applicable to 3 out of 30 deliveries. Of actually expedited deliveries, the algorithm agreed with expediting 75% of the time, 78% of which should have been delivered even earlier. Of actually nonexpedited deliveries, the algorithm would have only expedited 7% of those. CONCLUSION: The Clark 2017 Category II FHT algorithm had a lower sensitivity for predicting severe fetal acidemia and recommending expedited delivery. Although only 47% of babies with severe acidemia were delivered in expedited fashion, the Clark algorithm would only have expedited delivery in 30% overall.