Hyperfibrinolysis During Caesarean Section and Vaginal Delivery: A Prospective Cross-Sectional Study in the Delivery Room

<b>Introduction</b>: Postpartum hemorrhage remains a leading cause of maternal morbidity and mortality worldwide. While antifibrinolytic agents such as tranexamic acid are effective in treating established postpartum hemorrhage, the benefit of prophylactic tranexamic acid remains debated. The presence and frequency of early postpartum hyperfibrinolysis during routine childbirth have not been thoroughly investigated. <b>Material & Methods</b>: This prospective observational study was registered on ClinicalTrials.gov (NCT05975112) and conducted at the Medical University Hospital Graz between June 2023 and June 2024. Blood samples were collected from 413 women immediately after umbilical cord clamping; 379 were included in the analysis-291 undergoing Caesarean section and 88 vaginal delivery. Hyperfibrinolysis was assessed using thromboelastography and defined as an LY30 value > 8%. Additional coagulation parameters-including fibrinogen, D-dimer, activated partial thromboplastin time, and prothrombin time-were measured. Correlation analyses between viscoelastic and conventional parameters were performed using Pearson's correlation coefficients. <b>Results</b>: No cases of clinically significant hyperfibrinolysis (LY30 > 8%) were observed. However, 15.5% of women showed elevated LY30 values (>0%). LY30 values were significantly higher in vaginal deliveries compared to Caesarean sections (<i>p</i> = 0.003). A moderate correlation between maximum amplitude (MA) and fibrinogen was observed (r = 0.52), strongest in vaginal deliveries (r = 0.65). Other correlations were weak or negligible. <b>Conclusions</b>: Clinically relevant hyperfibrinolysis was not observed immediately postpartum in women without hemorrhage. These findings are consistent with current guidelines recommending tranexamic acid for therapeutic rather than routine prophylactic use. Viscoelastic testing may be useful for rapid assessment in early-stage bleeding. Further research should explore fibrinolytic activity later in the postpartum period.