CONTEXT: Severe preeclampsia significantly increases maternal and fetal risks. Prediction models like the fullPIERS model assist in identifying women at high risk, enabling timely interventions (e.g. corticosteroids, magnesium sulfate, and early delivery) to improve outcomes. OBJECTIVE: This study aimed to evaluate the diagnostic accuracy of the fullPIERS model in predicting maternal and fetal complications in a clinical setting. METHODS: A prospective study was conducted on 204 preeclamptic women from three tertiary hospitals. Data on complications, symptoms, and biomarkers were collected. The PIERS score based on the following factors: gestational age at diagnosis, presence of chest pain and/or dyspnea, maternal blood oxygen saturation (pulse oximetry), platelet count, serum creatinine and aspartate transaminase (AST) levels was used to predire maternal and fetalcomplications. Model performance was assessed using ROC analysis, and logistic regression identified independent predictors. RESULTS: The fullPIERS model achieved an accuracy of 75.3% (AUC: 0.753) for maternal, 83.2% (AUC: 0.832) for fetal, and 92.7% (AUC: 0.927) for combined maternal-fetal complications. Independent predictors of severe complications included: Moderate (ORa: 2.10) and severe hypertension (ORa: 10.08), SpO CONCLUSION: The fullPIERS model demonstrated excellent predictive capability for maternal and fetal complications in women with preeclampsia.