Association between estimated blood loss and hemoglobin decline in instrumental vaginal delivery: a retrospective crosssectional study in Riyadh, Saudi Arabia

<p><strong>Background:</strong> Instrumental vaginal delivery (IVD) is an essential component of obstetric care aimed at facilitating vaginal delivery and reducing maternal and neonatal morbidity and mortality. However, it may be associated with postpartum hemoglobin decline due to blood loss.</p> <p><strong>Objectives:</strong> To evaluate postpartum hemoglobin drop following IVD and determine whether Estimated blood loss (EBL) independently predicts clinically significant hemoglobin decline.</p> <p><strong>Design:</strong> Retrospective cross-sectional study.</p> <p><strong>Settings: </strong>National Guard Hospital, Riyadh, Saudi Arabia.</p> <p><strong>Patients and Methods: </strong>This study included 320 women who underwent IVD between September 2023 and October 2024. Data were collected from electronic medical records, including demographic characteristics, type of instrumental delivery, pre- and post-delivery hemoglobin levels, and EBL. Statistical analysis was performed using SPSS software.</p> <p><strong>Main Outcome Measures:</strong> Continuous hemoglobin drop and ≥2 g/dL decline.</p> <p><strong>Sample Size:</strong> Of 320 eligible patients, 297 with complete hematologic data were analyzed.</p> <p><strong>Results:</strong> Mean pre-delivery hemoglobin declined significantly postpartum (P < .001), and 19.9% experienced ≥2 g/dL reduction. EBL independently predicted hemoglobin decline (0.30 g/dL decrease per 100 mL; P < .001). Each 100 mL increase in EBL increased the odds of significant decline by 55% (OR 1.55; P < .001). ROC analysis showed acceptable discrimination (AUC 0.75). An EBL threshold of 400 mL yielded 80% sensitivity, 64% specificity, and 93% negative predictive value.</p> <p><strong>Conclusion: </strong>EBL independently predicts postpartum hemoglobin decline after IVD. A 400 mL threshold may help identify patients at risk for clinically significant reduction and guide selective early hemoglobin assessment.</p> <p><strong>Strengths:</strong> Targeted focus on instrumental deliveries, multivariable-adjusted analysis, and identification of a clinically actionable blood loss threshold.</p> <p><strong>Limitations:</strong> Retrospective design and reliance on visually estimated blood loss.</p> <p> </p>