Nomogram for predicting postpartum hemorrhage in women with hypertensive disorders of pregnancy

Postpartum hemorrhage (PPH) is a serious complication of hypertensive disorders of pregnancy (HDP) that can severely endanger maternal life. However, clinicians lack an HDP-specific, pre-delivery tool to quantify individual PPH risk. We aimed to develop and internally validate a nomogram for predicting PPH in patients with HDP. This retrospective single-center study included 480 women with HDP admitted between January 2022 and January 2025. PPH was defined as blood loss ≥ 500 mL after vaginal delivery or ≥ 1000 mL after cesarean section within 24 h. Patients were randomly assigned to a training set (n = 336) and a validation set (n = 144) in a 7:3 ratio. Clinical and laboratory variables, including systolic blood pressure (SBP), proteinuria, activated partial thromboplastin time (APTT), fibrinogen (FIB), 25-hydroxyvitamin D [25(OH)D], hepatocyte growth factor (HGF), and endothelin (ET), were analyzed by logistic regression to identify independent predictors for inclusion in the nomogram. Model performance was evaluated by area under the receiver operating characteristic curve (AUC), sensitivity, specificity, calibration curves, and decision curve analysis (DCA). Multivariate analysis indicated that SBP, proteinuria, APTT, and ET were independent risk factors for PPH in HDP patients, whereas FIB, 25(OH)D, and HGF were independent protective factors (P <0.05). The nomogram yielded an AUC of 0.895 (95% CI: 0.859-0.931; sensitivity 75.6%, specificity 86.2%) in the training set and 0.882 (95% CI: 0.811-0.953; sensitivity 78.9%, specificity 83.0%) in the validation set, with Hosmer-Lemeshow χ² = 2.114, p = 0.977 and χ² = 10.093, p = 0.259, respectively, indicating excellent discrimination and calibration. DCA indicated clinical net benefit across a wide range of threshold probabilities. This nomogram demonstrated high discrimination and good calibration for predicting PPH risk in women with HDP, with possible applicability in pre-delivery risk stratification. External validation is warranted before its application in routine clinical practice.