Postpartum hemorrhage: a continuing challenge

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.

Fibrinolytic potential as a risk factor for postpartum hemorrhage

Background

Postpartum hemorrhage (PPH) is still the leading cause of maternal morbidity and mortality worldwide. While impaired fibrin polymerization plays a crucial role in the development and progress of PPH, recent approaches using viscoelastic measurements have failed to sensitively detect early changes in fibrinolysis in PPH. This study aimed to evaluate whether women experiencing PPH show alterations in POC-VET fibrinolytic potential during childbirth and whether fibrinolytic potential offers benefits in the prediction and treatment of PPH.

Methods

Blood samples were collected at three different timepoints: T0 = hospital admission (19 h ± 18 h prepartum), T1 = 30-60 min after placental separation, and T2 = first day postpartum (19 h ± 6 h postpartum). In addition to standard laboratory tests, whole-blood impedance aggregometry (Multiplate) and viscoelastic testing (VET) were performed using the ClotPro system, which included the TPA-test lysis time, to assess the POC-VET fibrinolytic potential, and selected coagulation factors were measured. The results were correlated with blood loss and clinical outcome markers. Severe PPH was defined as a hemoglobin drop > 4g/dl and/or the occurrence of shock or the need for red blood cell transfusion.

Results

Blood samples of 217 parturient women were analyzed between June 2020 and December 2020 at Heidelberg University Women's Hospital, and 206 measurements were eligible for the final analysis. Women experiencing severe PPH showed increased fibrinolytic potential already at the time of hospital admission. When compared to non-PPH, the difference persisted 30-60 min after placental separation. A higher fibrinolytic potential was accompanied by a greater drop in fibrinogen and higher d-dimer values after placental separation. While 70% of women experiencing severe PPH showed fibrinolytic potential, 54% of those without PPH showed increased fibrinolytic potential as well.

Conclusion

We were able to show that antepartal and peripartal fibrinolytic potential was elevated in women experiencing severe PPH. However, several women showed high fibrinolytic potential but lacked clinical signs of PPH. The findings indicate that high fibrinolytic potential is a risk factor for the development of coagulopathy, but further conditions are required to cause PPH.

Impact of Hypertensive Disorders of Pregnancy on the Risk of Stroke Stratified by Subtypes and Follow-Up Time

BACKGROUND AND PURPOSE

Hypertensive disorders of pregnancy (HDP) comprise 4 subtypes. Previous studies have not investigated the relationship between stroke risk, different HDP subtypes, and follow-up time, which was the purpose of this study.

METHODS

Data of 17 588 women aged 18 to 45 years who had a history of HDP in Taiwan from 2000 to 2017 was retrospectively reviewed. After matching with confounders, 13 617 HDP women and 54 468 non-HDP women were recruited.

RESULTS

HDP women had an adjusted hazard ratio (aHR) of 1.71 (95% CI, 1.46-2.00) for stroke, and 1.60 (1.35-1.89) and 2.98 (2.13-4.18) for ischemic and hemorrhagic stroke, respectively (P<0.001 for all). The overall stroke risk in the HDP group was still 2.04 times 10 to 15 years after childbirth (1.47-2.83, P<0.001). Although the risks of both ischemic and hemorrhagic stroke persisted, their risk time trends were different. The risk of ischemic stroke reached peak during 1 to 3 years after childbirth with an aHR of 2.14 (1.36-3.38), while hemorrhagic stroke risk gradually increased and had an aHR of 4.64 (2.47-8.73) after 10 to 15 years of childbirth (both P<0.001). Among the 4 HDP subtypes, chronic hypertension with superimposed preeclampsia had the highest stroke risk (aHR=3.86, 1.91-7.82, P<0.001), followed by preeclampsia-eclampsia (aHR=2.00, 1.63-2.45, P<0.001), and gestational hypertension (aHR=1.68, 1.13-2.52, P<0.05); chronic preexisting hypertension had the lowest stroke risk (aHR=1.27, 0.97-1.68, P>0.05). Furthermore, multiple HDP combined with preeclampsia had aHR of 5.48 (1.14-26.42, P<0.05).

CONCLUSIONS

The effect of HDP on the risk of future stroke persisted for up to 17 years, both for ischemic and hemorrhagic strokes. The presence of multiple HDP and preeclampsia further increase the stroke risk.

Viscoelastic Hemostatic Assays for Postpartum Hemorrhage

This article discusses the importance and effectiveness of viscoelastic hemostatic assays (VHAs) in assessing hemostatic competence and guiding blood component therapy (BCT) in patients with postpartum hemorrhage (PPH). In recent years, VHAs such as thromboelastography and rotational thromboelastometry have increasingly been used to guide BCT, hemostatic adjunctive therapy and prohemostatic agents in PPH. The three pillars of identifying hemostatic competence include clinical observation, common coagulation tests, and VHAs. VHAs are advantageous because they assess the cumulative contribution of all components of the blood throughout the entire formation of a clot, have fast turnaround times, and are point-of-care tests that can be followed serially. Despite these advantages, VHAs are underused due to poor understanding of correct technique and result interpretation, a paucity of widespread standardization, and a lack of large clinical trials. These VHAs can also be used in cases of uterine atony, preeclampsia, acute fatty liver of pregnancy, amniotic fluid embolism, placental abruption, genital tract trauma, surgical trauma, and inherited and prepartum acquired coagulopathies. There exists an immediate need for a point-of-care test that can equip obstetricians with rapid results on developing coagulopathic states. The use of VHAs in predicting and treating PPH, although in an incipient state, can fulfill this need.

Prenatal Plasma Fibrinogen Level Predicts Postpartum Hemorrhage of Patients With HELLP Syndrome

Hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome is a serious complication of pregnancy. Postpartum hemorrhage indicates poor prognosis of pregnant women with HELLP syndrome. The aim of our study is to investigate the predictive value of coagulation markers for postpartum hemorrhage of pregnant women with HELLP syndrome. In a retrospective cohort study, 106 patients who were diagnosed as pregnant women with HELLP syndrome in Peking University Third Hospital from August 2010 to January 2017 were analyzed. The demographic characters of maternal and fetus, days of hospital stay, postpartum complications, and the laboratory tests of coagulation markers within 3 days before delivery were collected. In addition, 100 healthy pregnant women were collected as a control group. The result showed that the incidence of preeclampsia in pregnant women with postpartum hemorrhage was higher than that in pregnant women without hemorrhage (P = .011). The level of fibrinogen (FIB) in postpartum hemorrhage pregnant women with HELLP syndrome was lower than that in nonpostpartum hemorrhage pregnant women with HELLP syndrome and healthy pregnant women (2.3 [1.68-2.81] vs 3.64 ± 0.95, P = .000; 2.3 [1.68-2.81] vs 4.48 ± 0.62, P = .000). Multivariate analysis showed that decreased FIB levels independently predicted the postpartum hemorrhage of pregnant women with HELLP syndrome (odds ratio = 7.374, 95% confidence interval [CI], 1.551-35.05, P = .012). The receiver operating characteristic curve showed that the area under the curve of FIB level when predicting postpartum hemorrhage is 0.841 (95% CI, 0.708-0.976). When the cutoff value of FIB was 3.04 g/L, the sensitivity was 90.90% and the specificity was75.80%. Therefore, the low level of prenatal FIB is a reliable biomarker to predict postpartum hemorrhage of pregnant women with HELLP syndrome, which make it useful for pregnant women with HELLP syndrome in guiding surveillance therapy and prognosis assessment.

Remifentanil for Carboprost-Induced Adverse Reactions During Cesarean Delivery Under Combined Spinal-Epidural Anesthesia

Purpose

Carboprost may induce adverse reactions when used to treat postpartum hemorrhage. We aimed to explore the effects of intravenous infusion of low-dose remifentanil to prevent such reactions.

Methods

We enrolled parturient patients scheduled for elective cesarean section. Anesthesiologist administered combined spinal epidurals at the L3/4 interspace, with 0.5% hyperbaric bupivacaine subarachnoid space injections (1.5–2.5 ml). We randomly divided parturient patients, administered carboprost during surgery, into the remifentanil group (group R) and the control group (group C). Patients in group R received an intravenous target-controlled infusion of remifentanil (target effect-site concentration, 1.5 ng/ml) simultaneously with a carboprost tromethamine injection (250 µg). Patients in group C received a normal saline infusion with carboprost. We recorded and analyzed the incidence of carboprost-related adverse reactions (vomiting, nausea, chest congestion, flushing, hypertension, tachycardia, cough, and shivering), and assessed patient comfort using a numerical rating scale ([NRS], on which 0 was very uncomfortable and 10 was very comfortable).

Results

After applying inclusion and exclusion criteria, we conducted statistical analysis of the data from 70 women. The incidence of vomiting was significantly lower in group R than in group C (14.3 vs. 51.4%, p < 0.01); and the incidence of nausea, chest congestion, facial flushing, and hypertension were significantly lower in group R than in group C (all p < 0.01). Furthermore, the patients’ comfort scores were significantly higher in group R than in group C (8.0 ± 1.8 vs. 3.6 ± 2.1, p < 0.01).

Conclusion

Our results demonstrate that an intravenous low-dose remifentanil infusion can effectively prevent carboprost-related adverse reactions during cesarean delivery under combined spinal and epidural anesthesia.

Clinical Trial Registration

We pre-registered this study at http://www.chictr.org.cn/showproj.aspx?proj=27707 (ChiCTR1800016292).

Splenic Rupture and Postpartum Hemorrhage After Emergent Cesarean Delivery: A Case Report

Postpartum hemorrhage is a leading cause of maternal and fetal mortality. Although rare, peripartum splenic rupture (PSR) is a lethal cause of bleeding due to variable presentation and delayed diagnosis. A 22-year-old gravida 2, para 0, abortus 1 (G2P0A1) woman presented for premature rupture of membranes and was diagnosed with Influenza A and chorioamnionitis. She underwent emergent cesarean delivery under general anesthesia. Postoperatively, her condition worsened despite treatment for presumed sepsis. She was taken to the operating room for an exploratory laparotomy, and a splenectomy was performed for splenic rupture. We discuss management, risk factors, challenges, and importance of prompt treatment of PSR.

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

Rotational thromboelastometry (ROTEM) is a point-of-care viscoelastic method and enables to assess viscoelastic profiles of whole blood in various clinical settings. ROTEM-guided bleeding management has become an essential part of patient blood management (PBM) which is an important concept in improving patient safety. Here, ROTEM testing and hemostatic interventions should be linked by evidence-based, setting-specific algorithms adapted to the specific patient population of the hospitals and the local availability of hemostatic interventions. Accordingly, ROTEM-guided algorithms implement the concept of personalized or precision medicine in perioperative bleeding management (‘theranostic’ approach). ROTEM-guided PBM has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and health care costs. Accordingly, several randomized-controlled trials, meta-analyses, and health technology assessments provided evidence that using ROTEM-guided algorithms in bleeding patients resulted in improved patient’s safety and outcomes including perioperative morbidity and mortality. However, the implementation of ROTEM in the PBM concept requires adequate technical and interpretation training, education and logistics, as well as interdisciplinary communication and collaboration.

Vaginal Bleeding in Late Pregnancy

Bleeding in late-term pregnancy can present as an innocuous start to parturition or a catastrophic maternal-fetal hemorrhage masked by the physiologic adaptations of pregnancy. The emergency management of late-term bleeding can be challenging, especially when providing stabilizing care in a limited-resource environment. Early recognition of life-threatening vaginal bleeding, potential causes, and emergency management of maternal-fetal distress is reviewed. Maternal resuscitation with balanced versus targeted blood products replacement is presented for low-resource versus high-resource environments. Emergency department readiness for such a patient, in combination with appropriate consultation or transfer, is essential to the effective management of late-term vaginal bleeding.

Hemostatic issues in pregnancy-induced liver disease

Liver diseases may be accompanied by profound changes in the hemostatic system including thrombocytopenia, decreased plasma levels of pro- and anticoagulants, and alterations in plasma levels of fibrinolysis. The net effect of the hemostatic changes in chronic and acute liver diseases is a hemostatic system that is in relative balance due to the simultaneous decline in pro- and antihemostatic drivers. A unique category of liver diseases are those induced by pregnancy. In acute fatty liver of pregnancy, profound hemostatic changes occur, which may be caused by a combination of liver failure and disseminated intravascular coagulation. Hemostatic changes in preeclampsia and HELLP syndrome are dominated by thrombocytopenia, although alterations in plasmatic coagulation may also occur. Post-partum bleeds, bleeding from cesarean section wounds, and hepatobiliary bleeds may occur in both patient groups. Patients with intrahepatic cholestasis of pregnancy do not show clinically relevant hemostatic alterations, despite biochemical evidence of liver injury.