Elective Cesarean Preserves Maternal-Fetal Redox Homeostasis, Whereas Emergency Cesarean Disrupts It: A Prospective Observational Study Delivery Mode and Oxidative Stress

Abstract

Introduction: Oxidative stress is a key component of maternal-fetal physiology and varies with the mode of delivery. Labor induces hypoxia-reoxygenation cycles that elevate reactive oxygen species, whereas elective cesarean section (CS) occurs in a controlled metabolic environment. Emergency CS combines labor-related hypoxia with acute surgical stress. Comprehensive comparisons of maternal and cord oxidative profiles across all delivery modes remain limited. Methods: This prospective observational study included 126 term singleton pregnancies categorized as elective CS (n = 46), emergency CS (n = 39), or vaginal delivery (n = 41). Maternal blood was collected immediately before delivery and cord blood after birth. Total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and paraoxonase-1 (PON-1) activity were measured using automated RelAssay methods; OSI was calculated as (TOS/TAS)x100. Neonatal outcomes included Apgar scores and NICU admission. Group comparisons used ANOVA, Kruskal-Wallis, and chi-square tests, with ANCOVA adjusting for gestational age, maternal weight, diabetes, hypothyroidism, preeclampsia, and ASA use. Results: Baseline characteristics were comparable. Emergency CS had lower Apgar-1 scores and higher NICU admission. Maternal OSI (p = 0.002) and PON-1 (p = 0.004) differed significantly, with elective CS showing the most favorable profile. Cord TOS (p < 0.001), OSI (p < 0.001), and PON-1 (p = 0.001) were also highest in emergency CS. Delivery mode independently predicted maternal OSI and PON-1, and cord TOS, OSI, and PON-1 (all p < 0.01). Discussion: The pronounced oxidative shifts observed in emergency CS likely reflect the cumulative impact of prolonged labor, fetal distress, and abrupt surgical intervention. Elective CS, by avoiding labor-induced hypoxia and metabolic exhaustion, preserves a more balanced maternal-fetal redox environment. The parallel maternal and cord responses underscore the sensitivity of the fetoplacental unit to intrapartum oxidative changes. These findings clarify mechanistic differences between delivery modes and highlight redox status as a potential peripartum biomarker. Conclusion: Elective CS preserves maternal-fetal redox homeostasis, whereas emergency CS results in significant oxidative disruption and poorer neonatal adaptation. These findings support the potential use of oxidative stress markers as adjunct indicators of acute intrapartum stress when interpreted alongside established clinical parameters.