The inferior vena cava diameter is a useful ultrasound finding for predicting postpartum blood loss.

To assess whether the ultrasonographic measurement of the inferior vena cava (IVC) diameter in postpartum women is a useful parameter in evaluating the actual blood loss during delivery due to massive postpartum hemorrhage. In postpartum women with blood loss ≥500 g, abdominal ultrasonography was performed 1 hour after delivery. The IVC diameter was measured during inspiration (IVCi) and expiration (IVCe). The maternal heart rate, blood pressure, and shock index (heart rate/systolic blood pressure) were also measured. The predictive value of these parameters for severe anemia (hemoglobin <7.0 g/dL) a day after delivery was evaluated via receiver operating characteristic (ROC) analyses. Seven patients with severe anemia and 77 controls were included in the analysis. The area under the curve (AUC) for IVCi (0.905) and IVCe (0.926) was higher than that for the shock index (0.890), heart rate (0.874), or systolic blood pressure (0.752). Among the examined parameters, the best sensitivity was achieved by IVCe and systolic blood pressure (71.4%). The ultrasonographic measurement of the IVC diameter was found to be the most useful parameter in evaluating the actual maternal blood loss after delivery.