A 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.

Material 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 obstetrical complications known before delivery. We performed a 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: 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 large baby, pre-delivery maternal body mass index ≥25 kg/m2, and marginal or velamentous umbilical cord insertion, and two points to the history of postpartum hemorrhage. The sum of the points was defined as the predictive score. The cutoff 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.