Maternal protein S activity is associated with massive hemorrhage during caesarean section: retrospective case-control study

Women with severe postpartum hemorrhage have a decreased endogenous thrombin potential before delivery

BACKGROUND

Severe postpartum hemorrhage (PPH), defined as a blood loss ≥1000 mL, is associated with maternal morbidity and mortality.

OBJECTIVES

We aimed at characterizing coagulation properties of predelivery plasmas from pregnant women with thrombin generation assay and hemostatic biomarkers (plasminogen activator inhibitor-1, tissue factor [TF], and thrombomodulin).

METHODS

A nested case-control study was conducted within the "Study of Biological Determinants of Bleeding Postpartum," a French prospective cohort study, in order to compare women with severe PPH (cases) and controls matched for age, body mass index, term, and mode of delivery. Plasma was collected at entry in the delivery room, and blood loss was measured objectively. The predelivery endogenous thrombin generation potential (ETP) was measured in plasma using calibrated automated thrombinography and low TF concentration. Hemostatic biomarkers were measured using ELISA kits.

RESULTS

A total of 142 women (71 cases and 71 controls) were investigated. There was no difference in the median lag phase, thrombin peak, and time to peak between cases and controls. However, median predelivery ETP was lower in cases than in controls (2170 vs 2408 nM.min, P < .0001), independently of mode of delivery and PPH etiology. Median plasminogen activator inhibitor-1 and TF levels were higher in cases compared with controls (107.4 vs 68.1 ng/mL, P = .0003; 34.4 vs 27.4 pg/mL, P = .007), whereas thrombomodulin levels did not differ between the 2 groups.

CONCLUSION

Among thrombin generation assay parameters, predelivery ETP levels may have a predictive value for severe PPH.

Hemostatic biomarkers associated with postpartum hemorrhage: a systematic review and meta-analysis

Postpartum hemorrhage (PPH) is a leading cause of maternal morbi-mortality. Although obstetric risk factors are well described, the impact of predelivery hematologic and hemostatic biomarkers remains incompletely understood. In this systematic review, we aimed to summarize the available literature on the association between predelivery hemostatic biomarkers and PPH/severe PPH. Searching MEDLINE, EMBASE, and CENTRAL databases from inception to October 2022, we included observational studies on unselected pregnant women without bleeding disorder reporting on PPH and on predelivery hemostatic biomarkers. Two review authors independently performed title, abstract and full-text screening, upon which quantitative syntheses of studies reporting on the same hemostatic biomarker were conducted, calculating the mean difference (MD) between women with PPH/severe PPH and controls. A search on 18 October 2022 yielded 81 articles fitting our inclusion criteria. The heterogeneity between studies was considerable. With regard to PPH, the estimated average MD in the investigated biomarkers (platelets, fibrinogen, hemoglobin, Ddimer, activated partial thromboplastin time, and prothrombin time) were not statistically significant. Women who developed severe PPH had lower predelivery platelets than controls (MD = -26.0 109/L; 95% confidence interval, -35.8 to -16.1), whereas differences in predelivery fibrinogen concentration (MD = -0.31 g/L; 95% confidence interval, -0.75 to 0.13) and levels of factor XIII or hemoglobin were not statistically significant in women with and without severe PPH. Predelivery platelet counts were, on average, lower in women with severe PPH compared with controls, suggesting the potential usefulness of this biomarker for predicting severe PPH. This trial was registered at the International Prospective Register of Systematic Reviews as CRD42022368075.

Feasibility of using a handheld tissue hardness meter to quantify uterine contractions and its clinical application for obstetric bleeding management

Postpartum haemorrhage (PPH) is a potentially life-threatening condition. Women undergoing caesarean section (CS) are at particular risk, and improvements in the management of PPH during CS are required. We investigated the use of a tissue hardness metre to quantify uterine contractions during CS with a view to its application for obstetric bleeding management. Fifty pregnant women at term who underwent elective CS were recruited. Using a tissue hardness metre, we measured uterine hardness twice during CS: after placental removal and before peritoneum closure. Each measurement was conducted at two standardised points: fundus and corpus uteri. Concurrently, obstetricians subjectively graded uterine contractions as weak, medium, or strong. The hardness metre accurately quantified the degree of uterine contraction assessed by the obstetricians, and could be an effective clinical tool for early recognition of intra-operative massive bleeding. IMPACT STATEMENT What is already known on this subject? Maintaining adequate uterine contraction leads to prevention of excessive blood loss, which decreases the incidence and severity of PPH. However, the assessment of uterine contraction is currently judged by obstetricians, who manually and subjectively evaluate uterine contraction according to uterine hardness. Therefore, uterine atony remains a clinical diagnosis without a universal definition. What do the results of this study add? The present study investigated the use of a tissue hardness metre to quantify uterine contractions during CS with a view to its application for obstetric bleeding management. The hardness metre was able to quantify the degree of uterine contraction perceived by obstetricians. Quantifying uterine hardness during CS correlates with the amount of intra-operative bleeding and is useful for early recognition of massive haemorrhage. What are the implications of these findings for clinical practice and/or further research? To improve the management of atonic PPH and avoid serious complications, the tissue hardness metre should be considered as a potential clinical tool during CS.