The Role of Uterine Artery Doppler Analysis in Predicting the Amount of Postpartum Hemorrhage in Cesarean Section

Objective: Postpartum hemorrhage (PPH) most commonly occurs within the first 24 hours after delivery. During this period, the uterus undergoes physiological involution, accompanied by hemodynamic changes that reduce uterine blood flow. This early postpartum phase represents a critical window in which uterine artery Doppler (UAD) indices begin to change but may not yet reach peak values. We hypothesized that Doppler measurements obtained during this period could provide early insight into susceptibility to blood loss. This study aimed to evaluate whether UAD parameters can predict hemoglobin (Hb) decrease in the early postpartum period. Methods: A total of 56 low-risk pregnant women who underwent elective cesarean section were included. Bilateral UAD resistive index (RI) values were measured within the first 24 hours postpartum. Demographic characteristics and laboratory parameters were recorded. Mean UAD RI values were analyzed in relation to significant Hb decrease. Receiver operating characteristic analysis was performed to determine the optimal cut-off value of mean UAD RI associated with significant Hb decrease. Results: The 75th percentile of Hb change was 0.938 g/dL and was defined as the threshold for significant Hb decrease. A mean UAD RI value ≤0.915 was significantly associated with greater Hb decrease (p=0.025). A significant correlation was observed between mean UAD RI and preoperative Hb levels (r=-0.360, p=0.006). No significant correlation was found with other variables. Conclusion: Monitoring mean UAD RI values in the early postpartum period may serve as a complementary clinical parameter for the early identification of PPH. While current evidence on postpartum UAD measurements remains limited, UAD indices appear to undergo dynamic changes within the first 24 hours in cases complicated by PPH. These findings suggest that UAD assessment may contribute to early risk stratification and support clinical decision-making; however, further large-scale studies are required to validate these results.