Background and Objectives: Preoperative anaemia represents a key modifiable risk factor in obstetrics. Within the framework of Patient Blood Management (PBM), establishing precise hemoglobin (Hb) thresholds is essential for optimal clinical decision-making. This study aimed to assess the predictive value of preoperative hemoglobin levels and to determine the optimal cutoff associated with transfusion risk. Materials and Methods: A retrospective analysis was performed on 932 pregnant women. The association between preoperative hemoglobin, anticoagulant therapy, mode of delivery and maternal age with the need for red blood cell transfusion was evaluated using binary logistic regression and Receiver Operating Characteristic (ROC) curve analysis with the Youden index. Results: Red blood cell transfusion was required in 5.2% (n = 48) of the study population. Logistic regression identified preoperative hemoglobin as the strongest independent predictor (p < 0.001, OR = 0.216, 95% CI: 0.153–0.306), indicating that each 1 g/dL increase in Hb reduced the likelihood of transfusion by 78.4%. Anticoagulant therapy and age were not significant independent predictors (p > 0.05). ROC analysis demonstrated excellent predictive performance, with an Area Under the Curve (AUC) of 0.875 (95% CI: 0.823–0.927, p < 0.001). The optimal threshold for predicting transfusion risk was 10.9 g/dL (sensitivity: 89.6%, specificity: 60.5%). Conclusions: Preoperative hemoglobin concentration is the primary determinant of transfusion risk, outweighing the influence of clinical comorbidities. The integration of PBM protocols designed to sustain hemoglobin levels above 10.9 g/dL is essential to reduce perioperative transfusion requirements and to promote improved maternal safety and clinical outcomes.