Comparison of Postpartum Oxytocin Infusion Requirements in Patients Exposed to Oxytocin Prior to Caesarean Delivery Versus Patients Not Exposed

Abstract

Background: Postpartum haemorrhage (PPH) is a leading cause of maternal morbidity and mortality worldwide, with uterine atony being the primary etiology. Oxytocin remains the first-line uterotonic for prevention and treatment of PPH. However, prior intrapartum oxytocin exposure may induce receptor desensitization, reducing myometrial responsiveness in the immediate postpartum period. This study compared postpartum oxytocin infusion requirements in women exposed to oxytocin before caesarean delivery versus those not exposed.

Methods: This retrospective observational study was conducted at Sher-i-Kashmir Institute of Medical Sciences between 2019 and 2021. A total of 200 parturients undergoing caesarean delivery under neuraxial anaesthesia were included. Group A (n=100) had intrapartum oxytocin exposure for induction or augmentation, while Group B (n=100) did not. Demographic data, estimated blood loss, haemoglobin changes, oxytocin infusion rates, additional uterotonic use, and transfusion requirements were recorded. Statistical analysis was performed using t-test, Mann–Whitney U test, and Chi-square test, with p<0.05 considered significant.

Results: Group A patients were younger and more frequently nulliparous. They demonstrated higher estimated blood loss (762±166 vs 698±176 ml, p=0.009), greater haemoglobin drop (1.8±0.9 vs 1.2±0.7 g/dl, p<0.001), and higher need for high-rate oxytocin infusion (61% vs 32%, p<0.001). Additional uterotonics (53% vs 6%, p<0.001) and blood transfusions (41% vs 24%, p=0.012) were also more frequent in Group A.

Conclusion: Intrapartum oxytocin exposure significantly increases postpartum oxytocin infusion requirements and is associated with greater blood loss and higher need for adjunct uterotonics and transfusion. Anticipating this risk may help optimize uterotonic strategies and reduce PPH-related morbidity.