Abstract
BACKGROUND: Although monitoring systems for high-risk postpartum haemorrhage (PPH) are well-established, predicting immediate PPH-defined as blood loss ≥ 500 mL within 2 h postpartum, distinct from general PPH (≥ 500 mL within 24 h)-remains challenging in low-risk vaginal deliveries. This case-control study aimed to explore the association between predelivery coagulation profiles and the occurrence of immediate PPH in low-risk parturients, specifically those without severe pregnancy complications and with singleton vertex presentations. METHODS: A retrospective analysis was conducted on 409 vaginal deliveries at a tertiary hospital from 2014 to 2019. Of these, 179 cases met the WHO criteria for immediate PPH, while 230 served as controls (blood loss < 500 mL). Thirty clinical and laboratory variables were extracted, including predelivery coagulation parameters-platelet count (PLT), prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT)-as well as delivery characteristics such as forceps-assisted delivery and placental retention. Logistic regression was used to identify independent risk factors, and a multivariable prediction model was subsequently developed. RESULTS: Multivariate analysis identified several independent predictors of immediate PPH: Rural residence, Forceps deliveries, Retained placenta and membrane, Newborn birth weight ≥ 3500 g, PLT ≤ 212 × 10⁹/L, PT > 11 s, APTT > 28.8 s, and TT > 13.8 s. (all P < 0.05). The combined prediction model demonstrated excellent predictive performance, with an area under the receiver operating characteristic curve (AUC) of 0.854, achieving 82.58% sensitivity and 74.78% specificity. CONCLUSIONS: This multidimensional predictive model effectively identifies parturients at elevated risk for immediate PPH in low-risk deliveries, enabling more targeted preventive interventions. Prospective studies are warranted to validate and refine this model in broader clinical settings.