PAD Score: A Clinical Prediction Tool for Disseminated Intravascular Coagulation in Placental Abruption

Background/Objectives: Placental abruption remains one of the leading causes of maternal morbidity, and the development of disseminated intravascular coagulation (DIC) significantly worsens outcomes. We sought to develop and internally validate a prediction model-the Placental Abruption DIC (PAD) Score-using parameters routinely collected at presentation. Methods: We conducted a retrospective cohort study at a tertiary referral center in Istanbul, Turkey (January 2019-December 2024). Women with singleton pregnancies ≥22 weeks diagnosed with placental abruption were eligible. The primary outcome was overt disseminated intravascular coagulation (DIC) within 24 h of admission, adjudicated using the original International Society on Thrombosis and Haemostasis (ISTH) overt DIC scoring algorithm; a total score of ≥5 was considered compatible with overt DIC. We built a multivariable logistic regression model with bootstrap internal validation (1000 resamples). Robustness was evaluated through prespecified sensitivity analyses including complete-case analysis, single imputation, Firth-penalized logistic regression, exclusion of patients transferred from external facilities, a four-variable model excluding preeclampsia, and alternative score threshold grouping. Comparative discrimination against the admission ISTH overt DIC score, the Erez pregnancy-modified DIC score, and the Kobayashi obstetrical DIC score were evaluated using the area under the receiver operating characteristic curve and DeLong testing. Results: Of 237 women, 54 (22.8%) developed DIC. The final model retained five predictors: fibrinogen concentration, shock index, platelet count, placental separation percentage, and chronic hypertension/preeclampsia. The optimism-corrected area under the receiver operating characteristic curve (AUC) was 0.916, with calibration slope 0.96 and Brier score 0.12. DIC incidence was 2.9% in low-risk (0-4 points), 7.6% in moderate-risk (5-8 points), and 86.0% in high-risk (≥9 points) patients. Discrimination remained stable across complete-case (AUC 0.909), single-imputation (0.913), Firth-penalized (0.914), transfer-excluded (0.902), four-variable (0.892), reduced three-predictor (0.842, excluding fibrinogen and platelet count), pathology-confirmed subgroups (0.887) and composite clinical outcome (0.801) analyses, and exceeded that of the ISTH (0.812), Erez (0.848) and Kobayashi (0.793) comparator scores. Conclusions: The PAD Score offers a straightforward method for stratifying DIC risk in placental abruption. External validation in independent cohorts is needed before clinical implementation.