ClotPro® haemostasis in pregnancy: physiological parameters, reference intervals and comparison with non-pregnant women in a prospective observational study

Severe haemorrhage remains a leading cause of maternal mortality worldwide, despite advancements in obstetric care. Although viscoelastic testing is recommended to guide treatment of postpartum haemorrhage, device-specific physiological parameters and reference ranges specific to pregnancy are necessary to enable accurate interpretation of viscoelastic findings in the clinical management of obstetric patients. Evaluation of ClotPro®, including comparison with conventional laboratory assays and with non-pregnant individuals, is therefore essential to support its use in obstetric patients. In this prospective study, venous blood samples were obtained from 130 parturient participants before labour and 45 non-pregnant controls. Samples were analysed with conventional laboratory coagulation tests and the ClotPro® device. ClotPro® parameters and conventional laboratory tests were compared between the parturient population and non-pregnant control group with Student’s t-test or the Mann-Whitney U test, as appropriate. The correlation between selected laboratory and coagulation parameters was assessed with Spearman’s correlation coefficient. Reference ranges for ClotPro® in parturients were established by calculation of percentiles 2.5 and 97.5. Significant statistical differences in clot firmness were found across the EX-test, IN-test, and FIB-test (p < 0.006) between parturient and non-pregnant participants. The most pronounced differences were observed in the FIB-test. Strong correlation was observed between conventional laboratory tests and FIB-test (Rs = 0.657, p < 0.001 in the pregnant group; Rs = 0.669, p < 0.001 in the control group). According to our findings, reference ranges were established for the parturient population: EX-test, CT (39–67 s), A5 (39–59 mm), ML (1–9%), MCF (57–70 mm); FIB-test, A5 (15–29 mm), MCF (19–35 mm); and IN-test, CT (121–172 s). Pregnant women exhibit a distinct ClotPro® coagulation profile, characterised by increased clot firmness in FIB-test, supported by correlations with standard laboratory tests and parturient-specific reference intervals. These findings enhance the physiological interpretation of ClotPro® in obstetric care and may support its future integration into postpartum haemorrhage management.