Agnostic identification of plasma biomarkers for postpartum hemorrhage risk

BACKGROUND

Postpartum hemorrhage is difficult to predict, is associated with significant maternal morbidity, and is the leading cause of maternal mortality worldwide. The identification of maternal biomarkers that can predict increased postpartum hemorrhage risk would enhance clinical care and may uncover mechanisms that lead to postpartum hemorrhage.

OBJECTIVE

This retrospective case-control study employed agnostic proteomic profiling of maternal plasma samples to identify differentially abundant proteins in controls and postpartum hemorrhage cases.

STUDY DESIGN

Maternal plasma samples were procured from a cohort of >60,000 participants in a single institution's perinatal repository. Postpartum hemorrhage was defined as a decrease in hematocrit of ≥10% or receipt of transfusion within 24 hours after delivery. Postpartum hemorrhage cases (n=30) were matched by maternal age and delivery mode (vaginal or cesarean) with controls (n=56). Mass spectrometry was used to identify differentially abundant proteins using integrated peptide peak areas. Statistically significant differences between groups were defined as P<.05 after controlling for multiple comparisons.

RESULTS

By study design, cases and controls did not differ in race, ethnicity, gestational age at delivery, blood type, or predelivery platelet count. Cases had slightly but significantly lower predelivery and postdelivery hematocrit and hemoglobin. Mass spectrometry detected 1140 proteins, including 77 proteins for which relative abundance differed significantly between cases and controls (fold change >1.15, P<.05). Of these differentially abundant plasma proteins, most had likely liver or placental origins. Gene ontology term analysis mapped to protein clusters involved in responses to wound healing, stress response, and host immune defense. Significantly differentially abundant proteins with the highest fold change (prostaglandin D2 synthase, periostin, and several serine protease inhibitors) did not correlate with predelivery hematocrit or hemoglobin but identified postpartum hemorrhage cases with logistic regression modeling revealing good-to-excellent area under the operator receiver characteristic curves (0.802-0.874). Incorporating predelivery hemoglobin with these candidate proteins further improved the identification of postpartum hemorrhage cases.

CONCLUSION

Agnostic analysis of maternal plasma samples identified differentially abundant proteins in controls and postpartum hemorrhage cases. Several of these proteins are known to participate in biologically plausible pathways for postpartum hemorrhage risk and have potential value for predicting postpartum hemorrhage. These findings identify candidate protein biomarkers for future validation and mechanistic studies.

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.

Thromboelastometry-guided treatment algorithm in postpartum haemorrhage: a randomised, controlled pilot trial

BACKGROUND

Postpartum haemorrhage causes significant mortality among parturients. Early transfusion of blood products based on clinical judgement and conventional coagulation testing has been adapted to the treatment of postpartum haemorrhage, but rotational thromboelastometry (ROTEM) may provide clinicians means for a goal-directed therapy to control coagulation. We conducted a parallel design, randomised, controlled trial comparing these two approaches. We hypothesised that a ROTEM-guided protocol would decrease the need for red blood cell transfusion.

METHODS

We randomised 60 parturients with postpartum haemorrhage of more than 1500 ml to receive either ROTEM-guided or conventional treatment, with 54 patients included in the final analysis. The primary outcome was consumption of blood products, and secondarily we assessed for possible side-effects of managing blood loss such as thromboembolic complications, infections, and transfusion reactions.

RESULTS

The median (25th-75th percentile) number of RBC units transfused was 2 (1-4) in the ROTEM group and 3 (2-4) in the control group (P=0.399). The median number of OctaplasLG® units given was 0 in both groups (0-0 and 0-2) (P=0.030). The median total estimated blood loss was 2500 ml (2100-3000) in the ROTEM group and 3000 ml (2200-3100) in the control group (P=0.033). No differences were observed in secondary outcomes.

CONCLUSIONS

ROTEM-guided treatment of postpartum haemorrhage could have a plasma-sparing effect but possibly only a small reduction in total blood loss.

CLINICAL TRIAL REGISTRATION

NCT02461251.

Haemostatic support in postpartum haemorrhage: A review of the literature and expert opinion

Postpartum haemorrhage (PPH) remains the leading cause of pregnancy-related deaths worldwide. Typically, bleeding is controlled by timely obstetric measures in parallel with resuscitation and treatment of coagulopathy. Early recognition of abnormal coagulation is crucial and haemostatic support should be considered simultaneously with other strategies as coagulopathies contribute to the progression to massive haemorrhage. However, there is lack of agreement on important topics in the current guidelines for management of PPH. A clinical definition of PPH is paramount to understand the situation to which the treatment recommendations relate; however, reaching a consensus has previously proven difficult. Traditional definitions are based on volume of blood loss, which is difficult to monitor, can be misleading and leads to treatment delay. A multidisciplinary approach to define PPH considering vital signs, clinical symptoms, coagulation and haemodynamic changes is needed. Moreover, standardised algorithms or massive haemorrhage protocols should be developed to reduce the risk of morbidity and mortality and improve overall clinical outcomes in PPH. If available, point-of-care testing should be used to guide goal-directed haemostatic treatment. Tranexamic acid should be administered as soon as abnormal bleeding is recognised. Fibrinogen concentrate rather than fresh frozen plasma should be administered to restore haemostasis where there is elevated risk of fibrinogen deficiency (e.g., in catastrophic bleeding or in cases of abruption or amniotic fluid embolism) as it is a more concentrated source of fibrinogen. Lastly, organisational considerations are equally as important as clinical interventions in the management of PPH and have the potential to improve patient outcomes.

The role of fibrinogen in postpartum hemorrhage

Postpartum hemorrhage (PPH) is the leading cause of maternal death worldwide (WHO), with almost 60000 deaths annually. Pregnancy is a prothrombotic state with increased levels of several coagulation factors to protect the parturient from bleeding problems during delivery. Fibrinogen has a significant role in coagulation and bleeding. Studies have pointed out that lower fibrinogen levels before delivery, but also at the initiation of PPH, are predictive of major hemorrhage. Early, the goal-directed fibrinogen concentrate therapy might be very useful in a subgroup of patients with serious PPH. This review aims to summarize the current literature on fibrinogen during PPH.

Protocol for postpartum haemorrhage including massive transfusion

Postpartum haemorrhage (PPH) is one of the most common causes of maternal mortality worldwide. Management of PPH depends on the severity of bleeding. If the bleeding is severe, aorta compression can reduce bleeding. It should be followed by insertion of two coarse needles for intravenous access and blood sampling for haemoglobin and haemostasis. Further on, monitoring of vital parameters, as well as provision of extra oxygen and warm crystalloids, should be performed. Uterine atony is the most common cause of PPH and local guidelines for uterotonic drug selection should be followed. Patients with ongoing bleeding should immediately receive surgical care for bleeding control. During severe ongoing bleeding, haemostasis care includes early tranexamic acid, transfusion in ratio 4:4:1 (blood:plasma:platelets), and extra fibrinogen intravenously. If not severe PPH, use goal-directed therapy. During general anaesthesia and uterine atony, stop volatile anaesthesia and change to intravenous anaesthesia.

Placenta Accreta Spectrum Part II: hemostatic considerations based on an extended review of the literature

"Placenta accreta spectrum" (PAS) is a rare but serious pregnancy condition where the placenta abnormally adheres to the uterine wall and fails to spontaneously release after delivery. When it occurs, PAS is associated with high maternal morbidity and mortality-as PAS management can be particularly challenging. This two-part review summarizes current evidence in PAS management, identifies its most challenging aspects, and offers evidence-based recommendations to improve management strategies and PAS outcomes. The first part of this two-part review highlighted the general anesthetic approach, surgical and interventional management strategies, specialized "centers of excellence," and multidisciplinary PAS treatment teams. The high rates of PAS morbidity and mortality are often provoked by PAS-associated coagulopathies and peripartal hemorrhage (PPH). Anesthesiologists need to be prepared for massive blood loss, transfusion, and to manage potential coagulopathies. In this second part of this two-part review, we specifically reviewed the current literature pertaining to hemostatic changes, blood loss, transfusion management, and postpartum venous thromboembolism prophylaxis in PAS patients. Taken together, the two parts of this review provide a comprehensive survey of challenging aspects in PAS management for anesthesiologists.

Postpartum hemorrhage in maternal mothers at Anutapura Public Hospital in Palu, 2017

OBJECTIVE

Postpartum hemorrhage is one of the factors causing maternal mortality in Indonesia. In Indonesia, at least 128.000 women suffer from hemorrhage, causing them to death. Data from the Anutapura Public Hospital in Palu showed that the rate of postpartum hemorrhage within 2015-2017 was fluctuated and still caused maternal mortality. This study aimed to determine the risk factors of the incidence of postpartum hemorrhage in maternal mothers at Anutapura Public Hospital, Palu.

METHOD

The type of study was observational with a case-control approach. The subject of the study was mothers having a postpartum hemorrhage. The total sample of this study was 50 people as the case group and 100 people as the control group by adjusting the types of labor. Sampling was done using a total sampling technique. The data were analyzed using an odds ratio test with α=5%.

RESULT

This study showed that anemia (OR=2.874 and CI=1.421-5.812), parity (OR=3.995 and CI=1.952-8.174), age (OR=2.874 and CI=1.421-5.812) were the risk factors of postpartum hemorrhage in women.

CONCLUSION

The anemia, parity, and age are the risk factors of postpartum hemorrhage in women. The importance of increasing ANC (antenatal care) visits is to control maternal and fetal health and provide information through a medical consultation about the importance of planning a good pregnancy.

Factor XIII activity at onset of labour and association with postpartum haemorrhage: an exploratory post-hoc study

BACKGROUND

Platelets, fibrinogen and factor XIII (FXIII) are required to form a stable clot in case of haemorrhage. The aims of this study were to evaluate a possible association between FXIII activity at the onset of labour and postpartum haemorrhage (PPH), and to ascertain whether FXIII activity at labour onset differs from after delivery.

METHODS

FXIII activity in 239 women with PPH (blood loss >1 L) and in 76 women without PPH was compared, as was activity before and after delivery in a third group of 80 women.

RESULTS

FXIII activity at onset of labour was significantly lower in the PPH group compared with the control group (mean ± SD 0.98 ± 0.20 vs 1.05 ± 0.17 kIU/L; P=0.0006). The difference was significantly greater in subgroups having vaginal delivery with no oxytocin stimulation or uterine exploration (absolute difference 0.131; 95% CI 0.055 to 0.206), compared with a subgroup experiencing any complication (0.04; 95% CI -0.023 to 0.104; interaction P-value 0.098). There was a weak but statistically significant inverse correlation between FXIII and estimated blood loss (r=-0.25; P=0.030) in the control group but not the PPH group. There was no significant difference between FXIII activity at onset of labour and after delivery (mean ± SD 1.03 ± 0.17 vs 1.04 ± 0.19 kIU/L; P=0.093).

CONCLUSIONS

At the onset of labour women with a subsequent PPH had significantly lower mean FXIII activity than that of women without PPH. This difference was small and within normal limits. FXIII activity did not change during normal delivery. The importance of FXIII during PPH requires study.

Point-of-care blood clotting test and its correlation with fibrinogen level: Potential in goal-directed transfusion in postpartum hemorrhage

OBJECTIVE

To study the correlation of conventional point-of-care clotting test (POCCT) of whole blood with laboratory fibrinogen levels in women with primary major postpartum hemorrhage (PPH) to generate evidence regarding its potential in rationalizing transfusion of blood components for supplementing fibrinogen.

METHODS

A total of 68 samples were studied: 40 from women with primary major PPH, 20 from women without PPH, and eight samples of Fresh Frozen Plasma (FFP). POCCT was performed in the PPH and non-PPH groups and at the same time, sample for laboratory fibrinogen was sent. Values were correlated using Pearson's correlation coefficient (r). Depending upon the laboratory fibrinogen values, POCCT in the PPH group was divided into three subgroups of less than 7, 7-11, and more than >11 min as subgroups 1, 2, and 3, respectively.

RESULTS

Women in the PPH group (n = 40) had a mean fibrinogen level of 346.15 ± 143.37 mg% with a significant negative correlation with POCCT (r = -0.69, P < 0.001). Mean fibrinogen levels of non-PPH group and FFP samples were 602.1 ± 169.72 and 286.75 ± 103.42 mg%, respectively. PPH subgroups 1, 2, and 3 had mean fibrinogen of 452.2 ± 141.8, 332.58 ± 138.51, and 158.71 ± 145 mg%, respectively. These values may potentially guide FFP transfusions.

CONCLUSION

POCCT is easy, costs nothing and has a potential role in rationalizing FFP transfusion in low- and middle-income countries.

Antepartum fibrinogen concentration as a predictor of bleeding complications

Objective: The objective of this study was to examine the predictive value of fibrinogen concentration for bleeding complications among women presenting for delivery and for whom a fibrinogen level was measured before delivery.Study design: This was a nested case-control study using a cohort of all women who delivered at our institution from October 2001 to July 2016 and in whom a fibrinogen concentration was obtained within 48 hours before delivery. We identified all cases that had one or more of the following events: (1) postpartum hemorrhage; (2) postpartum hysterectomy; (3) transfusion of select blood products; or (4) a ≥ 33% decrease in hematocrit from the first hematocrit measured during the hospital stay to any subsequent hematocrit value drawn either simultaneously with or following the fibrinogen concentration measurement. We included the first case or control delivery for a given woman. Controls were the next one or two consecutive deliveries without a bleeding complication and matched for number of fetuses. We used logistic regression to calculate the odds ratio and 95% confidence intervals and calculated the area under the receiver operating characteristic curve.Results: We identified 424 cases and 801 controls. The mean predelivery fibrinogen concentration was significantly lower in cases (425 ± 170 mg/dL) than controls (523 ± 122 ng/mL) for all case types combined (p < .001) and for each case type individually (all p < .001). For every 100-mg/dL decrease in fibrinogen, the odds of a bleeding complication increased 1.63 times (95% confidence interval: 1.48-1.80). However, the area under the receiver operating characteristic curve was poor (0.69; 95% confidence interval: 0.65-0.72). Below 300 mg/dL there were 104 (24.5%) cases and 31 (3.9%) controls, yielding high specificity (96.1%) but extremely low sensitivity (24.5%). We could not identify a cutoff value that yielded acceptable values of both sensitivity and specificity.Conclusions: Antepartum fibrinogen concentration was significantly lower among women who developed bleeding complications, though these differences may not be large enough to provide clinically meaningful critical values. Nevertheless, a higher threshold for the critical value during pregnancy should be considered.

Fibrinogen for the management of critical obstetric hemorrhage

AIM

In cases of critical obstetric hemorrhage leading to extreme hypofibrinogenemia, fibrinogen is the marker that indicates the critical severity, and early fibrinogen supplementation centering on hemostatic resuscitation is a vital treatment to stabilize a catastrophic condition. In this review, we investigated the effect of fibrinogen level on hemostasis and what we can do to treat hypofibrinogenemia efficiently and improve patients' outcome.

METHODS

We reviewed numerous articles related to hypofibrinogenemia in critical obstetric hemorrhage. Especially, we performed a systematic review on target value of fibrinogen for hemostasis and effectiveness of fibrinogen concentrate. We also reviewed the articles about the methods for early normalization of fibrinogen level such as tranexamic acid, massive transfusion protocol, and point-of-care testing.

RESULTS

The target value of fibrinogen calculated by needs for massive transfusion was 200 mg/dL or 10 mm of A5_FIBTEM . Although fibrinogen concentrate worked poorly on fibrinogen levels within the normal range, it improved the blood fibrinogen levels rapidly when it was administered to critical obstetric hemorrhage patients with serious hypofibrinogenemia. Hence, the volume of FFP transfused could be reduced along with a reduction in the frequency of pulmonary edema due to volume overload.

CONCLUSION

The patient group for which fibrinogen concentrate works most effectively is cases with severe hypofibrinogenemia. Further research is required in the light of evidence. The essence of the transfusion algorithm in critical obstetric hemorrhage is to approach the target value for obtaining hemostasis, ensure an accurate and prompt grasp of the severity using point-of-care testing, introduce a massive transfusion protocol and use tranexamic acid.

Can prepartum thromboelastometry-derived parameters and fibrinogen levels really predict postpartum hemorrhage?

BACKGROUND

Decreased postpartum rotational thromboelastometric parameters of coagulation (ROTEM®) and fibrinogen levels have been associated with postpartum hemorrhage (PPH). However, the predictive power of prepartum ROTEM® parameters and fibrinogen levels (Fbgpre) for PPH remains unknown.

METHODS

This prospective observational pilot study included 217 healthy pregnant women. Maximum clot firmness (FIBTEM-MCF), fibrinogen levels and standard coagulation parameters were measured upon admission to the delivery room for labor and within 1 h after vaginal delivery. Blood loss was measured with a calibrated collecting drape during the third stage of labor. PPH was defined as blood loss ≥500 mL. Predictors for bleeding were identified via receiver operating characteristic analyses and bivariate and multivariate regression analyses.

RESULTS

Women with and without PPH did not differ in median FIBTEM-MCF [23 mm (25th percentile 20 mm, 75th percentile 26 mm) vs. 23 mm (19 mm, 26 mm), respectively; P=0.710] or mean Fbgpre (4.57±0.77 g/L vs. 4.45±0.86 g/L, respectively; P=0.431). Blood loss and prepartum coagulation parameters were not correlated (FIBTEM-MCF, rs=-0.055, P=0.431; Fbgpre, rs=-0.017, P=0.810). The areas under the curves (predictive power for PPH) for FIBTEM-MCF and Fbgpre and were 0.52 (0.41-0.64, P=0.699) and 0.53 [95% confidence interval (95% CI) 0.40-0.65, P=0.644], respectively. Neither FIBTEM-MCF nor Fbgpre was associated with PPH. However, primiparity [odds ratio (OR) 4.27, 95% CI 1.32-13.80, P=0.015) and urgent cesarean section (2.77, 1.00-7.67, P=0.050) were independent predictors of PPH.

CONCLUSIONS

ROTEM® parameters, Fbgpre and postpartum blood loss were not associated, nor did these factors predict PPH. Sufficiently powered prospective studies are needed to confirm these results.

Postpartum hemorrhage: a continuing challenge

Obstetric hemorrhage remains a leading cause of maternal morbidity and mortality worldwide. Many postpartum hemorrhages (PPHs) do not have identifiable risk factors; maternity units should therefore have obstetric hemorrhageprotocols in place for all parturients as every pregnancy has the potential to be complicated by hemorrhage. This review will examine the epidemiology of PPH as well as current recommendations for key elements in obstetric hemorrhage protocols. Recent advances in hematologic management of PPH will be also be reviewed, including: (1) recognition of hypofibrinogenemia as a risk factor for severe PPH, (2) use of antifibrinolytic therapy, and (3) strategies for fibrinogen replacement therapy.