Predictive score for postpartum hemorrhage in vaginal deliveries following frozen embryo transfer

Objective: To develop a predictive score for life-threatening severe postpartum hemorrhage in vaginal deliveries following frozen embryo transfer. Materials and Methods: We conducted a retrospective cohort study of 315 singleton vaginal deliveries following frozen embryo transfer from 2017 to 2022. Severe postpartum hemorrhage was defined as hemorrhage exceeding 1500 mL. A predictive score was generated from maternal characteristics and obstetric complications before delivery. We performed multivariable logistic regression analysis using 2017-2020 data and assigned points to identified risk factors. The predictive score’s accuracy was evaluated using 2021-2022 data. Results: A large baby (birth weight ≥3500 g), pre-delivery maternal body mass index ≥25 kg/m2, marginal or velamentous umbilical cord insertion, and history of postpartum hemorrhage were identified as risk factors. We assigned one point to a large baby, a pre-delivery maternal body mass index ≥25 kg/m2, and marginal or velamentous umbilical cord insertion, and two points to a history of postpartum hemorrhage. The sum of the points was defined as the predictive score. The cut-off was set at two points, with a score ≥2 points being the high-risk group and a score ≤1 point being the low-risk group. The predictive score demonstrated a sensitivity of 47.8%, specificity of 85.4%, positive predictive value of 45.8%, and negative predictive value of 86.4% in the 2021-2022 validation cohort. Conclusion: The predictive score identified severe postpartum hemorrhage in approximately half of the high-risk cases. Implementing measures such as autologous blood storage may facilitate rapid response during heavy bleeding and improve maternal prognosis.