Prolonged Fetal Heart Rate Decelerations in Labor: Can We Reduce Unplanned Primary Cesarean Sections in This Group?

Introduction: Non-reassuring fetal tracing is the second leading cause of primary cesarean delivery in the United States. Prolonged fetal heart rate decelerations are non-reassuring fetal heart rate characteristics, which do not uniformly predict poor fetal outcome but can prompt obstetricians to proceed with cesarean delivery. The objective of this manuscript is to identify a strategy to reduce the primary cesarean section rate in patients with prolonged fetal heart rate decelerations in labor.

Methods: This is a retrospective cohort study over a 5-year period at an academic medical center, including patients undergoing primary cesarean section following labor induction, augmentation, or spontaneous labor who were noted to have prolonged fetal heart rate deceleration(s) in the 1 h prior to the time of delivery. Two groups were compared: "crash" cesarean sections versus "emergent" cesarean sections. The primary outcome was if fetal heart tones were rechecked in the operating room prior to cesarean section incision. Secondary outcomes included maternal-fetal monitoring versus Doppler fetal heart tones in the operating room, return to baseline noted in the operating room, fetal outcomes, fetal monitoring characteristics, and anesthesia type between crash versus emergent groups.

Results: Of 1969 term singleton cesarean sections, 119 patients met our inclusion criteria (emergent group n = 80) (crash group n = 39), which accounted for 13.9% of all primary cesarean sections during the study period. The emergent group had a significantly higher rate of reassessment of fetal heart tones in the operating room n = 61 (76.2%) versus the crash group n = 15 (38.4%) (p ≤ 0.0001). There were no statistically significant differences regarding fetal outcomes between the two groups. The crash group had a higher rate of category 1 fetal heart rate tracing prior to the prolonged deceleration, a longer median prolonged deceleration, and a deeper median nadir of the prolonged deceleration; these differences were statistically significant. The prolonged-to-delivery interval was significantly shorter in the crash group (median = 15 min) than tin he emergent group (median = 33 min) (p ≤ 0.0001). The crash group also had a higher rate of general anesthesia (n = 11, 28.2%) than the emergent group (n = 6, 7.5%) (p = 0.002). The crash group was specifically investigated. Of the 15 patients with fetal heart tones rechecked in the crash group, 7 had returned to baseline in the operating room, but underwent cesarean section without fetal monitoring.

Conclusion: Our results indicate that the practice of placing patients on fetal monitor upon arrival to the operating room prior to performing crash cesarean delivery could reduce the rate of primary cesarean deliveries performed for prolonged decelerations in labor. When fetal heart tones have returned to baseline upon arrival in the operating room, the decision to proceed with cesarean delivery can be reconsidered. However, many clinical factors must be taken into consideration, and the decision to proceed is ultimately at the discretion of the obstetrics provider.