RESUMO
PURPOSE: Postpartum haemorrhage (PPH) is a leading cause of maternal mortality and morbidity. Our aim was to investigate the relationships between antenatal factor XIII (FXIII), fibrinogen levels, and blood loss at childbirth. METHODS: This prospective observational study evaluated an unselected cohort of pregnant women admitted for intended vaginal deliveries of singletons at term. To determine clotting factor levels, we obtained blood samples at a maximum of three days prior to vaginal delivery. A calibrated collecting drape was used to quantify blood loss in the third stage of labour. Moderate and severe PPH were diagnosed as blood losses ≥ 500 mL and ≥ 1000 mL, respectively. In a multiple logistic regression analysis, we determined whether coagulation factors and their interactions could independently predict (severe) PPH. RESULTS: We analysed 548 vaginal deliveries that occurred during the study period. Of those, 78 (14.2%) lost ≥ 500 mL and 18 (3.3%) lost ≥ 1000 mL of blood. The mean pre-delivery FXIII activity in women with PPH (79.33% ± 15.5) was significantly (p < 0.001) lower than in women without PPH (86.45% ± 14.6). A receiver operating characteristic curve analysis detected antenatal FXIII cutoff levels of 83.5% and 75.5% for PPH and severe PPH, respectively. The multiple logistic regression analysis showed that FXIII alone (p < 0.001) and its interaction with fibrinogen (p = 0.03) significantly predicted PPH. FXIII was not significantly correlated with blood loss among patients with severe PPH. CONCLUSION: Our results suggested that antenatal FXIII levels may have a significant influence on PPH. The interaction between FXIII and fibrinogen might also provide slight advantages in forecasting PPH.