Characterization of antithrombin levels in pregnancy

Hemostasis in Pre-Eclamptic Women and Their Offspring: Current Knowledge and Hemostasis Assessment with Viscoelastic Tests

Pre-eclampsia (PE) is a placenta-mediated disease and remains a major cause of maternal and neonatal mortality and morbidity. As PE develops, normal pregnancy's hypercoagulable balance is disrupted, leading to platelet hyperactivation, excessive pathological hypercoagulability, and perturbed fibrinolysis. This narrative review aims to summarize the current knowledge regarding hemostasis in PE compared with healthy gestation and the potential effects of maternal PE on neonatal hemostasis. Finally, it aims to discuss hemostasis assessments for normal pregnancies and PE, emphasizing the role of viscoelastic tests, namely, thromboelastography (TEG) and thromboelastometry (ROTEM), for monitoring PE-associated hemostatic alterations. The use of TEG/ROTEM for assessing the hemostatic profile of PE women has been little considered, even though conventional coagulation tests (CCTs) have not helped to monitor hemostasis in this population. Compared with normal pregnancy, TEG/ROTEM in PE reveals an excessive hypercoagulability analogous with the severity of the disease, characterized by higher-stability fibrin clots. The TEG/ROTEM parameters can reflect PE severity and may be used for monitoring and as predictive markers for the disease.

Study on the predictive value of serum hypersensitive C-reactive protein, homocysteine, fibrinogen, and omentin-1 levels with gestational diabetes mellitus

Objective: To investigate whether hypersensitive C-reactive protein (Hs-CRP), homocysteine, fibrinogen, and omentin-1 could predict gestational diabetes mellitus (GDM) risk. Methods: Case-control study was conducted at Hengshui People's Hospital. The GDM group included data about 150 patients aged between 22 and 35 years in 24-28 weeks. An equivalent comparative control group without GDM was composed of the same pool of patients. Body mass index (BMI), total cholesterol (TC), triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), oral glucose tolerance test (OGTT) 0-2h, hs-CRP, homocysteine, fibrinogen, and omentin-1 levels were studied in the serum samples of research groups. Univariate logistic regression analysis was used to explore the risk factors of GDM. The area under the curve (AUC) was calculated by the receiver operating characteristic curve (ROC) to analyze the predictive values. Results: Hs-CRP, homocysteine, and fibrinogen in GDM group were significantly higher than those in non-GDM group. Omentin-1 were significantly lower than those in non-GDM group. Logistic regression showed that hs-CRP, homocysteine, fibrinogen, and omentin-1 were risk factors for GDM. The AUC of the established GDM risk prediction model was 0.977, and the sensitivity and specificity were 92.10% and 98.70%, respectively; which were greater than that of hs-CRP, homocysteine, fibrinogen, and omentin-1 alone. Conclusions: Hs-CRP, homocysteine, fibrinogen, and omentin-1 in pregnancy have important clinical value for the prediction of GDM. We used these laboratory indications to establish a GDM risk prediction model that allows for early detection and treatment of GDM, lowering the morbidity of maternal and infant complications.

Integration of clinical demographics and routine laboratory analysis parameters for early prediction of gestational diabetes mellitus in the Chinese population

Gestational diabetes mellitus (GDM) is one of the most common complications in pregnancy, impairing both maternal and fetal health in short and long term. As early interventions are considered desirable to prevent GDM, this study aims to develop a simple-to-use nomogram based on multiple common risk factors from electronic medical health records (EMHRs). A total of 924 pregnant women whose EMHRs were available at Peking University International Hospital from January 2022 to October 2022 were included. Clinical demographics and routine laboratory analysis parameters at 8-12 weeks of gestation were collected. A novel nomogram was established based on the outcomes of multivariate logistic regression. The nomogram demonstrated powerful discrimination (the area under the receiver operating characteristic curve = 0.7542), acceptable agreement (Hosmer-Lemeshow test, P = 0.3214) and favorable clinical utility. The C-statistics of 10-Fold cross validation, Leave one out cross validation and Bootstrap were 0.7411, 0.7357 and 0.7318, respectively, indicating the stability of the nomogram. A novel nomogram based on easily-accessible parameters was developed to predict GDM in early pregnancy, which may provide a paradigm for repurposing clinical data and benefit the clinical management of GDM. There is a need for prospective multi-center studies to validate the nomogram before employing the nomogram in real-world clinical practice.

A Comprehensive Review of Risk Factors for Venous Thromboembolism: From Epidemiology to Pathophysiology

Venous thromboembolism (VTE) is the third most common cause of death worldwide. The incidence of VTE varies according to different countries, ranging from 1-2 per 1000 person-years in Western Countries, while it is lower in Eastern Countries (<1 per 1000 person-years). Many risk factors have been identified in patients developing VTE, but the relative contribution of each risk factor to thrombotic risk, as well as pathogenetic mechanisms, have not been fully described. Herewith, we provide a comprehensive review of the most common risk factors for VTE, including male sex, diabetes, obesity, smoking, Factor V Leiden, Prothrombin G20210A Gene Mutation, Plasminogen Activator Inhibitor-1, oral contraceptives and hormonal replacement, long-haul flight, residual venous thrombosis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, trauma and fractures, pregnancy, immobilization, antiphospholipid syndrome, surgery and cancer. Regarding the latter, the incidence of VTE seems highest in pancreatic, liver and non-small cells lung cancer (>70 per 1000 person-years) and lowest in breast, melanoma and prostate cancer (<20 per 1000 person-years). In this comprehensive review, we summarized the prevalence of different risk factors for VTE and the potential molecular mechanisms/pathogenetic mediators leading to VTE.

Antithrombin Therapy: Current State and Future Outlook

Antithrombin (AT) is a natural anticoagulant pivotal in inactivating serine protease enzymes in the coagulation cascade, making it a potent inhibitor of blood clot formation. AT also possesses anti-inflammatory properties by influencing anticoagulation and directly interacting with endothelial cells. Hereditary AT deficiency is one of the most severe inherited thrombophilias, with up to 85% lifetime risk of venous thromboembolism. Acquired AT deficiency arises during heparin therapy or states of hypercoagulability like sepsis and premature infancy. Optimization of AT levels in individuals with AT deficiency is an important treatment consideration, particularly during high-risk situations such as surgery, trauma, pregnancy, and postpartum. Here, we integrate the existing evidence surrounding the approved uses of AT therapy, as well as potential additional patient populations where AT therapy has been considered by the medical community, including any available consensus statements and guidelines. We also describe current knowledge regarding cost-effectiveness of AT concentrate in different contexts. Future work should seek to identify specific patient populations for whom targeted AT therapy is likely to provide the strongest clinical benefit.

Laboratory Testing of Hemostasis in Pregnancy: A Brief Overview

Normal pregnancy is associated with significant physiological changes in the coagulation and fibrinolytic systems with an inclination toward a hypercoagulable state. This includes an increase in plasma levels of most clotting factors, a decrease in endogenous anticoagulants, and inhibition of fibrinolysis. Although these changes are critical in maintaining placental function and reducing postpartum hemorrhage, they may contribute to an increased risk of thromboembolism, particularly toward the end of pregnancy and during puerperium. Hemostasis parameters and the non-pregnant population reference ranges cannot be used in the assessment of bleeding or thrombotic complication risk during pregnancy, and pregnancy-specific information and reference ranges are not always available to support the interpretation of laboratory tests. This review aims to summarize the use of relevant hemostasis tests to promote evidence-based interpretation of laboratory test results as well as discuss challenges associated with testing during pregnancy.

Application Value of Predictive Model Based on Maternal Coagulation Function and Glycolipid Metabolism Indicators in Early Diagnosis of Gestational Diabetes Mellitus

Objective

To investigate whether first-trimester fasting plasma glucose (FPG), blood coagulation function and lipid metabolism could predict gestational diabetes mellitus (GDM) risk.

Methods

From October 2020 to May 2021, a total of 584 pregnant women who took prenatal care in Shanghai Jiaotong University Affiliated Sixth People's Hospital were chosen as the observation subjects. The clinical information and serum samples of all pregnant women were collected at 10–13 weeks of gestation and the blood coagulation function, fasting blood glucose and lipid profiles of the pregnant women were detected. A 75 g oral glucose tolerance test was performed up to 24–28 weeks of gestation. One hundred forty-two pregnant women with GDM and 442 pregnant women without GDM were detected. Data were expressed by x ± s or median (interquartile range) and were analyzed using student's t-test, Wilcoxon rank sum test and Logistic regression analysis. The area under the curve (AUC) was calculated by receiver operating characteristic curve (ROC) to analyze the predictive values.

Results

Compared with non-GDM group, age, pre-pregnancy BMI, FPG, FIB, D-Dimer, FDP, FPG, TC, TG, LDL-C, sdLDL-C, APOB and APOE in GDM group were significantly higher than those in non-GDM group, while PT, INR, APTT and TT were significantly lower than those in non-GDM group. Univariate logistic regression analysis was used to explore the risk factors of GDM. Gestational age, pre-pregnancy BMI, FPG, PT, INR, APTT, FIB, TT, D-Dimer, TC, TG, LDL-C, sdLDL-C, APOB and APOE were all independent predictors of GDM. Multivariatelogistic regression showed that pre-pregnancy BMI, FPG, APTT, TT, TG, LDL-C, sdLDL-C and APOB were risk factors for GDM. The AUC of the established GDM risk prediction model was 0.892 (0.858–0.927), and the sensitivity and specificity were 80.71 and 86.85%, respectively; which were greater than that of pre-pregnancy BMI, FPG, APTT, TT,TG, LDL-C, sdLDL-C, APOB alone, and the difffference was statistically signifificant (P < 0.05).

Conclusions

FPG, APTT, TT, TG, LDL-C, sdLDL-C, APOB and pre-pregnancy BMI in early pregnancy has important clinical value for the prediction of GDM, We combined these laboratory indicators and established a GDM risk prediction model, which is conducive to the early identification, intervention and treatment of GDM, so as to reduce the morbidity of maternal and infant complications.

An update on the physiologic changes during pregnancy and their impact on drug pharmacokinetics and pharmacogenomics

For many years, the medical community has relied in clinical practice on historic data about the physiological changes that occur during pregnancy. However, some newer studies have disputed a number of assumptions in these data for not being evidence-based or derived from large prospective cohort-studies. Accurate knowledge of these physiological changes is important for three reasons: Firstly, it facilitates correct diagnosis of diseases during pregnancy; secondly, it enables us to answer questions about the effects of medication during pregnancy and the ways in which pregnancy alters pharmacokinetic and drug-effects; and thirdly, it allows for proper modeling of physiologically-based pharmacokinetic models, which are increasingly used to predict gestation-specific changes and drug-drug interactions, as well as develop new knowledge on the mode-of-action of drugs, the mechanisms underlying their interactions, and any adverse effects following drug exposure. This paper reviews new evidence regarding the physiologic changes during pregnancy in relation to existing knowledge.

Liver and Biliary Disease of Pregnancy and Anesthetic Implications: A Review

Liver and biliary disease complicates pregnancy in varying degrees of severity to the mother and fetus, and anesthesiologists may be asked to assist in caring for these patients before, during, and after birth of the fetus. Therefore, it is important to be familiar with how different liver diseases impact the pregnancy state. In addition, knowing symptoms, signs, and laboratory markers in the context of a pregnant patient will lead to faster diagnosis and treatment of such patients. This review article discusses changes in physiology of parturients, patients with liver disease, and parturients with liver disease. Next, general treatment of parturients with acute and chronic liver dysfunction is presented. The article progresses to specific liver diseases with treatments as they relate to pregnancy. And finally, important aspects to consider when anesthetizing parturients with liver disease are discussed.

Integrated trajectories of the maternal metabolome, proteome, and immunome predict labor onset

Estimating the time of delivery is of high clinical importance because pre- and postterm deviations are associated with complications for the mother and her offspring. However, current estimations are inaccurate. As pregnancy progresses toward labor, major transitions occur in fetomaternal immune, metabolic, and endocrine systems that culminate in birth. The comprehensive characterization of maternal biology that precedes labor is key to understanding these physiological transitions and identifying predictive biomarkers of delivery. Here, a longitudinal study was conducted in 63 women who went into labor spontaneously. More than 7000 plasma analytes and peripheral immune cell responses were analyzed using untargeted mass spectrometry, aptamer-based proteomic technology, and single-cell mass cytometry in serial blood samples collected during the last 100 days of pregnancy. The high-dimensional dataset was integrated into a multiomic model that predicted the time to spontaneous labor [R = 0.85, 95% confidence interval (CI) [0.79 to 0.89], P = 1.2 × 10^-40, N = 53, training set; R = 0.81, 95% CI [0.61 to 0.91], P = 3.9 × 10^-7, N = 10, independent test set]. Coordinated alterations in maternal metabolome, proteome, and immunome marked a molecular shift from pregnancy maintenance to prelabor biology 2 to 4 weeks before delivery. A surge in steroid hormone metabolites and interleukin-1 receptor type 4 that preceded labor coincided with a switch from immune activation to regulation of inflammatory responses. Our study lays the groundwork for developing blood-based methods for predicting the day of labor, anchored in mechanisms shared in preterm and term pregnancies.

Effect of blood loss during caesarean section on coagulation parameters

INTRODUCTION

Venous thrombosis is the leading cause of pregnancy-related maternal morbidity and mortality. The thrombosis risk is increased by caesarean section and blood loss, though underlying mechanisms of these prothrombotic changes remain unknown.

MATERIALS AND METHODS

This prospective study recruited 50 pregnant women at term undergoing elective caesarean section at University Hospital Magdeburg, Germany. Blood loss during surgery was correlated with the changes in total protein S, full length TFPI (TFPI_fl), prothrombin, the endogenous thrombin potential (ETP) and resistance to activated protein C (APCsr) determined via calibrated automated thrombography.

RESULTS

Mean blood loss was 506 ml (95%CI: 456 to 557 ml). Total protein S was 0.63 (95%CI: 0.60 to 0.67) U/ml preoperatively, decreased by 14.8% after caesarean section and almost normalised five days later. TFPI_fl was 0.47 (95%CI: 0.41 to 0.53) U/ml before, remained unchanged immediately after and increased by 11.5% five days after surgery. Prothormbin was 1.10 (95%CI: 1.03 to 1.16) U/ml preoperatively, reduced by 10.4% immediately after and increased again five days after caesarean section, exceeding the preoperative values by 4.4% (-0.7 to 9.6). The ETP decreased by 3.9%, whereas the APCsr increased by 37.0% immediately after caesarean section. The changes in total protein S, prothrombin, thrombin generation and APC resistance showed a trend to be more pronounced in the subgroups with higher blood loss.

DISCUSSION

Moderate blood loss during caesarean section hardly reduces thrombin generation but aggravates pregnancy-induced APC resistance and combined deficiency of TFPI and protein S, which can account for the increased thrombosis risk in early puerperium.

Serological Parameters and Vascular Investigation for a Better Assessment in DVT during Pregnancy-A Systematic Review

Pregnancy and the postpartum period represent a condition characterized by a thrombotic predisposition. The majority of pregnant women do not face acute or severe thrombotic events. In general, mild inconveniences such as leg swelling or moderately painful thrombotic events (phlebitis) are encountered. However, when pregnancy is associated with inherited or acquired deficits that affect homeostasis, the risk of acute or even life-threatening events can increase significantly. The major consequence is the loss of the fetus or the venous thromboembolism that endangers the mother's life. Venous thromboembolism is caused by deep vein thrombosis, therefore timely detection and especially the assessment of the extent of the thrombotic event are crucial. In this paper we have summarized the most important paraclinical investigations. The study emphasizes the importance of selecting the methods of investigation. The right choice allows establishing a correct diagnosis and individualizing the treatment.

Anatomical and physiological alterations of pregnancy

The extensive metabolic demands of pregnancy require specific physiological and anatomical changes. These changes affect almost all organ systems, including the cardiovascular, respiratory, renal, gastrointestinal, and hematologic system. The placenta adds another layer of complexity. These changes make it challenging for clinicians to understand presenting signs and symptoms, or to interpret laboratory and radiological tests. Furthermore, these physiological alterations can affect the pharmacokinetics and pharmacodynamics of drugs. Drug safety in lactation is only supported by limited evidence. In addition, the teratogenic effects of medications are often extrapolated from animals, which further adds uncertainties. Unfortunately, pregnant women are only rarely included in clinical drug trials, while doses, regimens, and side effects are often extrapolated from studies conducted in non-pregnant populations. In this comprehensive review, we present the changes occurring in each system with its effects on the pharmacokinetic variables. Understanding these physiological changes throughout normal pregnancy helps clinicians to optimize the health of pregnant women and their fetuses. Furthermore, the information on pregnancy-related physiology is also critical to guide study design in this vulnerable 'orphan' population, and provides a framework to explore pregnancy-related pathophysiology such as pre-eclampsia.

Managing thromboembolic risk in patients with hereditary and acquired thrombophilias

While we are now able to diagnose inherited thrombophilias in a substantial number of patients with venous thromboembolism (VTE), the initial hope that their presence would inform recurrence risk and thus decisions on anticoagulation duration has largely been disappointing. Indeed, the presence or absence of transient provoking risk factors has proven to be the most important determinant of VTE recurrence risk. Thus, particular attention to transient acquired risk factors for VTE remains paramount, as they have generally been shown to carry more prognostic weight than inherited thrombophilias. The presence of other acquired risk factors may require additional management considerations, whether pertaining to anticoagulant choice, as in antiphospholipid antibody syndrome, or to addressing a new predisposing medical condition, as in malignancy. Antithrombin deficiency or the presence of ≥1 thrombophilic defect may be exceptions that can have a role in prognostication; however, as illustrated in this review through several case vignettes, interpretation and clinical application of the results of inherited thrombophilia testing is nuanced. We have chosen to focus on cases in which patients have been identified as having thrombophilic defects rather than the indications for undertaking testing in the first place or the extent of investigation. Management decisions in such cases ultimately hinge on individualized consideration of the benefits and risks of anticoagulation along with patient preference rather than on an algorithmic pathway based on thrombophilia status.

Human PZP and common marmoset A2ML1 as pregnancy related proteins

While pregnancy-related proteins (PRP) are known to contribute to immunotolerance during pregnancy, their significance to development of invasive placenta is unclear. We compared PRP expression in humans and the common marmoset (Callithrix jacchus), a new-world monkey. Invasive placenta was observed at the maternal-foetal interface of marmoset placenta from green fluorescent protein (GFP)-expressing foetus and wild type mother. The pregnancy zone protein (PZP) and alpha-2 macroglobulin-like 1 (A2ML1) proteins exhibited the most prominent increase in expression during the second trimester in humans and marmoset, respectively. In humans, PZP accumulated at the maternal-foetal interface and A2ML1 accumulated in the amnion. Similarly, A2ML1 mRNA was detected in marmoset placenta. These proteins belong to the A2M family of protease inhibitors, and both PZP and A2ML1 share around 90% homology between human and marmoset and have highly conserved structures. However, the protease-reacting bait regions of the proteins had lower homology (56.8–60.7% in proteins) relative to the rest of the sequence. Notably, the cleavage site of a proinflammatory proline-endopeptidase was preserved in human PZP and marmoset A2ML1. These proteins contain multiple sites that are cleaved by proteases involving proline-endopeptidase. Systemic regulation of these A2M family proteins may be important in animals with invasive placenta.

Recommendations for clinical laboratory testing for antithrombin deficiency; Communication from the SSC of the ISTH

Hereditary deficiency of antithrombin, a natural anticoagulant, causes a thrombophilia with a high risk for venous thromboembolism. Guidance for laboratory testing to diagnose antithrombin deficiency include the use of an activity assay for initial testing, performing an antigen test and activity-to-antigen ratio when the activity level is low, using pediatric reference ranges until the age of 6 months, excluding acquired causes of low antithrombin (e.g. liver dysfunction, proteinuria, heparin, disseminated intravascular coagulation, thrombosis, surgery) or falsely normal/elevated results (e.g. argatroban, bivalirudin, dabigatran in factor IIa-based assays; rivaroxaban, apixaban, edoxaban, but not betrixaban in Xa-based assays). Molecular testing, if available, may help determine the risk for thrombosis as this might vary among the different mutations. Moreover, it will identify mutations that can be missed by traditional activity assays. Strategies for interpreting laboratory test results are provided.

Physiological changes of pregnancy and the Swansea criteria in diagnosing acute fatty liver of pregnancy

The Swansea criteria are used to assess the likelihood of acute fatty liver of pregnancy. There are significant physiological changes in normal pregnancy in several of the pathology parameters used in the Swansea criteria. This may impact the sensitivity and specificity of the Swansea criteria. Five of the 11 case series reporting laboratory values in acute fatty liver of pregnancy used values divergent from the Swansea criteria. When using the Swansea criteria for diagnosis of acute fatty liver of pregnancy, using pregnancy-specific and/or laboratory-specific reference intervals is recommended. Simpler diagnostic criteria using parameters of hepatocellular damage and hepatic synthetic dysfunction may be an alternative to the Swansea criteria, and further studies investigating the sensitivity and specificity of these parameters would be useful.

Review article: Investigations and the pregnant woman in the emergency department - part 1: Laboratory investigations

Accurate assessment of the pregnant patient in the ED depends on knowledge of physiological changes in pregnancy, and how these changes may impact on pathology tests, appearance on point-of-care ultrasound and electrocardiography. In addition the emergency physician needs to be cognisant of disorders that are unique to or more common in pregnancy. Part 1 of this review addresses potential deviations in laboratory investigation reference intervals resulting from physiological alterations in pregnancy, and the important causes of abnormal laboratory results in pregnancy. Part 2 will address the role of point-of-care ultrasound in pregnancy, physiological changes that may affect interpretation of point-of-care ultrasound, physiological changes in electrocardiography, and the safety of radiological procedures in the pregnant patient.

Estimates of Within-Subject Biological Variation of Protein C, Antithrombin, Protein S Free, Protein S Activity, and Activated Protein C Resistance in Pregnant Women

BACKGROUND

In pregnancy, interpretation of results from coagulation parameters can be difficult because of the procoagulant physiological changes. The aim of this study was to describe the course of 5 coagulation parameters (thrombophilia markers) in healthy pregnancies, and to estimate and compare the within-subject biological variation (CVI) of these parameters in healthy pregnant and nonpregnant women.

METHODS

Blood samples were obtained every 4th week during pregnancy and 3 samples after delivery in 20 healthy women and every 4th week during 40 weeks in 19 healthy nonpregnant women. Protein C (PC), antithrombin (AT), protein S free (PS free), protein S activity (PS activity), and activated protein C resistance (with factor V–depleted plasma) (APCR) were analyzed. Before the calculation of CVI, results were transformed into multiples of the median (MoM) and natural logarithm of MoM (lnMoM) to adjust for the physiological changes during pregnancy.

RESULTS

During pregnancy, PC results showed large variability, AT decreased slightly, and PS free and PS activity decreased significantly. Both activated partial thromboplastin time tests used to calculate APCR decreased, and the APCR ratio was constant. The CVI (lnMoM) in pregnancy were for PC 8.4%, for AT 3.8%, for PS free 11.5%, for PS activity 9.3%, and for APCR 0.5%, and similar to corresponding results in nonpregnant women.

CONCLUSIONS

Transformation of coagulation parameters in healthy pregnancies to lnMoM is a tool to establish a kind of steady state. Although there is a physiological change in PC, AT, and PS free and PS activity during pregnancy, the CVI was comparable with the CVI of nonpregnant women.

'To test or not to test', the arguments for and against thrombophilia testing in obstetrics

Clinicians increasingly investigate women for thrombophilias due to their associations with venous thromboembolism and placenta-mediated pregnancy complication. These associations, however, are modest and based largely on retrospective data from studies with heterogeneous classifications and populations, leading to discordance between evidence and guidelines. Current evidence suggests a contributory rather than causative role for thrombophilia in placenta-mediated pregnancy complication and venous thromboembolism. With little evidence of benefit from antithrombotic therapy in placenta-mediated pregnancy complication, thrombophilia screening remains controversial. Given the low absolute risk of placenta-mediated pregnancy complication and gestational venous thromboembolism with heritable thrombophilia, universal screening is inappropriate. Selective screening for antiphospholipid syndrome is supported by robust evidence of benefit. Conversely, selective screening for heritable thrombophilia has not been shown to effectively manage placenta-mediated pregnancy complication. Therefore, at present heritable thrombophilia screening is not warranted for placenta-mediated pregnancy complication. Until we have better evidence from better stratified patient groups, caution should remain if we wish to practice evidence-based medicine.

Antithrombin: anti-inflammatory properties and clinical applications

Many humoral and cellular components participate in bidirectional communication between the coagulation and inflammation pathways. Natural anticoagulant proteins, including antithrombin (AT), tissue factor pathway inhibitor, and protein C, suppress proinflammatory mediators. Conversely, inflammation blunts anticoagulant activity and, when uncontrolled, promotes systemic inflammation-induced coagulation, such as those that occur in disseminated intravascular coagulation and severe sepsis. This review discusses the mechanisms of action and clinical use of AT concentrate in critically ill patients and in the settings of perioperative anticoagulation management for surgery and obstetrics. AT is a serine protease inhibitor with broad anticoagulant activity and potent anti-inflammatory properties. In clinical conditions associated with hereditary or acquired AT deficiency, administration of AT concentrate has been shown to restore proper haemostasis and attenuate inflammation. Of note, AT modulates inflammatory responses not only by inhibiting thrombin and other clotting factors that induce cytokine activity and leukocyte-endothelial cell interaction, but also by coagulation-independent effects, including direct interaction with cellular mediators of inflammation. An increasing body of evidence suggests that AT concentrate may be a potential therapeutic agent in certain clinical settings associated with inflammation. In addition to the well-known anticoagulation properties of AT for the treatment of hereditary AT deficiency, AT also possesses noteworthy anti-inflammatory properties that could be valuable in treating acquired AT deficiency, which often result in thrombotic states associated with an inflammatory component.

Thrombosis in pregnancy and maternal outcomes

Pregnancy increases the risk of thrombosis four- to five-fold. Seventy-five to eighty percent of pregnancy-related thrombotic events are venous and twenty to -twenty-five percent are arterial. The main reason for the increased risk is hypercoagulability. Women are hypercoagulable because they have evolved so that they are protected against the bleeding challenges of pregnancy, miscarriage, or childbirth. Both genetic and acquired risk factors can further increase the risk of thrombosis. The maternal consequences of thrombosis of pregnancy include permanent vascular damage, disability, and death. While the maternal outcomes of thrombosis can be modified by anticoagulation therapy, management of thrombosis during pregnancy is the subject of another paper in this issue (see paper by B. Konkle). This review will focus on the epidemiology, pathophysiology, risk factors, and maternal consequences of thrombosis in pregnancy.