Association Between Laboratory Coagulation Parameters and Postpartum Hemorrhage in Preterm and Term Caesarean Section: A Retrospective Analysis

<b>Background:</b> Deranged antepartum laboratory parameters may be risk factors for postpartum hemorrhage (PPH). However, whether this is also valid in women who give birth prematurely is currently unknown. <b>Methods:</b> We performed a retrospective single-center study to assess the role of antepartum hemoglobin, platelet count, fibrinogen, activated partial thromboplastin time, and prothrombin time as risk factors for PPH following caesarean section. We defined PPH as documented blood loss of at least 1 L and/or transfusion of red blood cell concentrates. We stratified the included patients according to gestational age: extremely preterm (gestational age < 28 weeks), very preterm (gestational age between 28 and 32 weeks), late and moderate preterm (gestational age between 32 and 37 weeks), and term (gestational age ≥ 37 weeks). <b>Results:</b> We included 1734 patients, 112 (6%) of whom had PPH. In total, 19 patients (10%) were in the extremely preterm group, 13 patients (10%) were in the very preterm group, 44 patients (9%) were in the late and moderate preterm group, and 36 patients (4%) were in the term group. Hemoglobin predicted PPH in all gestational age groups. Platelet count was associated with PPH in term, but not in preterm patients. Fibrinogen was associated with PPH in late prematurity but not in term patients and not in patients with early or extreme prematurity. <b>Conclusions:</b> Antepartum hemoglobin was the only factor predicting PPH in preterm and term caesarean sections. Platelet count and fibrinogen concentration were associated with PPH in term and late prematurity, respectively, but not in earlier stages of prematurity.