Antiphospholipid antibodies and the risk of severe and non-severe pre-eclampsia: the NOHA case-control study

Preeclampsia and the Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is characterized by venous or arterial thrombosis and/or adverse pregnancy outcome in the presence of persistent laboratory evidence of antiphospholipid antibodies (aPLs). Preeclampsia complicates about 10-17% of pregnancies with APS. However, only early onset preeclampsia (<34 weeks of gestation) belongs to the clinical criteria of APS. The similarities in the pathophysiology of early onset preeclampsia and APS emphasize an association of these two syndromes. Overall, both are the result of a defective trophoblast invasion and decidual transformation at early gestation. Women with APS are at increased risk for prematurity; the reasons are mostly iatrogenic due to placental dysfunction, such as preeclampsia or FGR. Interestingly, women with APS have also an increased risk for preterm delivery, even in the absence of FGR and preeclampsia, and therefore it is not indicated but spontaneous. The basic treatment of APS in pregnancy is low-dose aspirin and low-molecular-weight heparin. Nevertheless, up to 20-30% of women develop complications at early and late gestation, despite basic treatment. Several additional treatment options have been proposed, with hydroxychloroquine (HCQ) being one of the most efficient. Additionally, nutritional interventions, such as intake of vitamin D, have shown promising beneficial effects. Curcumin, due to its antioxidant and anti-inflammatory properties, might be considered as an additional intervention as well.

Added value of antiphosphatidylserine/prothrombin antibodies in the workup of obstetric antiphospholipid syndrome: communication from the ISTH SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies

BACKGROUND

The added value of antiphosphatidylserine/prothrombin antibodies (aPS/PT) in the diagnostic workup of antiphospholipid syndrome (APS) is unclear. Currently, diagnosis of thrombotic APS (TAPS) and obstetric APS (OAPS) requires persistent presence of lupus anticoagulant (LAC), anticardiolipin (aCL) immunoglobulin (Ig) G/IgM, or anti-β2-glycoprotein I (aβ2GPI) IgG/IgM antibodies.

OBJECTIVES

To evaluate the role of aPS/PT IgG and IgM in OAPS.

METHODS

aPS/PT IgG/IgM, aCL IgG/IgM, aβ2GPI IgG/IgM, and LAC were determined in 653 patients (OAPS, TAPS, and controls). In-house aPS/PT cut-off values were calculated, titers and prevalence were compared between OAPS, TAPS, and controls and type of pregnancy morbidity. Sensitivity, specificity, likelihood ratios, and odds ratios (OR) with 95% CI were calculated.

RESULTS

In OAPS, aPS/PT IgG and IgM showed an OR of 4.32 (95% CI, 2.54-7.36) and 3.37 (95% CI, 1.93-5.89), respectively, but the association was not independent of LAC. Prevalence and titers of aPS/PT IgG and IgM were lower in OAPS than in patients with TAPS. aPS/PT were more prevalent and showed higher titers in patients with late pregnancy loss than in patients with early pregnancy loss with a positivity of 86.4% and 39.3%, respectively. Higher aPS/PT titers did not increase the likelihood of having OAPS.

CONCLUSION

The added value of aPS/PT testing in the current diagnostic workup of OAPS seems limited compared with LAC, aCL, and aβ2GPI. aPS/PT might be useful in specific subsets of patients with OAPS. However, future multicentric studies are needed to elucidate the risk of less frequent and most severe obstetrical manifestations.

Evolution of Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune prothrombotic disease characterized by thrombosis and/or pregnancy complications caused by antiphospholipid antibodies (aPL). The history of APS can be traced back to observations made during screening programs for syphilis conducted in the mid-20th century, with identification of patients with the so-called biological false-positive serological reactions for syphilis. Initial observation linking aPL with recurrent miscarriages was first reported more than 40 years ago. Since then, our understanding of the pathogenesis and management of APS has evolved markedly. Although APS is an autoimmune disease, anticoagulation mainly with vitamin K antagonists (VKAs) rather than immunomodulation, is the treatment of choice for thrombotic APS. Direct acting oral anticoagulants are inferior to VKAs, especially those with triple-positive APS and arterial thrombosis. Inflammation, complement activation, and thrombosis in the placenta may contribute to pathogenesis of obstetric APS. Heparin, mainly low-molecular-weight heparin, and low-dose aspirin represent the treatments of choice for women with obstetric complications. Increasingly, immunomodulatory agents such as hydroxychloroquine for thrombotic and obstetric APS are being used, especially in patients who are refractory to present standard treatment.

Antiphospholipid Syndrome in Pregnancy: New and Old Pathogenetic Mechanisms

The antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized, according to the Sydney criteria, by the persistent presence of autoantibodies directed against phospholipid-binding proteins associated with thrombosis and/or obstetrical complications. The most frequent complications in obstetric antiphospholipid syndrome are recurrent pregnancy losses and premature birth due to placental insufficiency or severe preeclampsia. In recent years, vascular APS (VAPS) and obstetric APS (OAPS) have been described as two different clinical entities. In VAPS, antiphospholipid antibodies (aPL) interfere with the mechanisms of coagulation cascade and the 'two hit hypothesis' has been suggested to explain why aPL positivity does not always lead to thrombosis. OAPS seems to involve additional mechanisms, such as the direct action of anti-β2 glycoprotein-I on trophoblast cells that can lead to a direct placental functional damage. Furthermore, new actors seem to play a role in the pathogenesis of OAPS, including extracellular vesicles, micro-RNAs and the release of neutrophil extracellular traps. The aim of this review is to investigate the state-of-the-art antiphospholipid syndrome pathogenesis in pregnancy, in order to provide a comprehensive overview of both old and new pathogenetic mechanisms involved in this complex disease.

Antiphospholipid Antibodies in Pregnancy: Maternal and Neonatal Implications

Antiphospholipid antibodies (aPL Abs) have long been associated with the occurrence of certain specific pregnancy morbidities, affecting both mother and fetus. Antithrombotic-based prophylactic regimens are the standard of care. Their intensity is modulated by the thrombotic history and has greatly improved the prognosis related to spontaneous morbidity. Observational studies show that this treatment is still associated with the persistence of excess of late-pregnancy placental diseases, calling for new or complementary developments, yet to be validated. Rigorous prospective multicentric validation of clinical and laboratory parameters capable of identifying those women and fetuses at a risk of pejorative evolution, thus early prognosis, is a priority issue. These will make it possible to develop customized treatments and test them. Furthermore, there are still concerns, particularly neurodevelopmental ones, about children born to aPL Ab-positive mothers, and clarification based on regular, more systematic evaluations is required. Even after pregnancy, women with a pure obstetrical antiphospholipid syndrome are at a greater risk of venous and arterial thrombosis over time, and prevention needs to be improved. These women also appear to develop more psychiatric and mood disorders. Central nervous system imaging using high-resolution techniques has shown subtle impairments in the white matter, associated with the most pathogenic aPL Abs and the clinical significance of this is under investigation. These mothers also seem to develop an excess of cancers. The systemic impact of aPL Abs is gradually being suspected, although this requires further evidence, and prevention should be envisaged.

Antiphospholipid Syndrome and Preeclampsia in Pregnancy: A Case Report

Antiphospholipid syndrome (APS) refers to a clinical autoimmune syndrome characterized by arterial or venous thrombosis and pregnancy morbidities, such as fetal loss after the 10th week of gestation, recurrent miscarriages, or intrauterine growth restriction. This study describes a case of preeclampsia in a 37-year-old primiparous woman in the 30th week of pregnancy with a lack of prior thrombotic history. The birth of a dead neonate and the findings of placenta thrombosis raised the suspicion of APS, which was confirmed by the finding of antibodies. A description of the treatment, which is still under investigation, follows. In our case, tissue sections were stained followed by observation. Various placental changes were detected with the presence of placental intravascular thrombi. The most important finding of this case study is the presence of severe preeclampsia in the setting of APS, with no previous medical history. In conclusion, antiphospholipid syndrome can be directly related to preeclampsia during pregnancy, leading to complications that may be preventable if immediate medical intervention is available.

[Thrombotic microangiopathy in rheumatology: a link between thrombosis and autoimmunity]

Uncontrolled hypercoagulation and inflammation (thromboinflammation), which are both independent and closely related and amplifying each other pathological processes, form the basis for pathogenesis of a wide range of diseases and complications, including immuno-inflammatory (autoimmune) rheumatic diseases, with the development of potentially fatal injuries of internal organs. Thrombotic microangiopathy is one of the most prominent prototypes of thromboinflammatory pathological conditions. The close link between environmental factors, hemostasis genetic defects and the complement system, inflammation and autoimmunity as pathogenetic mechanisms of microthrombosis draws particular attention to studying thrombotic microangiopathy in immuno-inflammatory rheumatic diseases, primarily systemic lupus erythematosus, antiphospholipid syndrome and scleroderma renal crisis. In future, these studies may be important for expanding the idea of the role of autoimmune mechanisms in pathogenesis of critical hemostasis disorders in human diseases, and for developing new approaches to therapy. Recently, special attention has been paid to the treatment of systemic lupus erythematosus and antiphospholipid syndrome with eculizumab, which is humanized monoclonal IgG2/4k antibody that blocks the complement component C5a and the membrane attack complex (C5b-9) formation, and which is registered for the treatment of atypical hemolytic uremic syndrome, paroxysmal nocturnal hemoglobinuria, as well as severe forms of myasthenia gravis and neuromyelitis optica. Further studies in this direction will create prerequisites for improving the prognosis not only in patients with orphan disorders, but also for widespread human diseases.

Are concentrations of clusterin and beta-2-glycoprotein I dysregulated in HIV associated preeclampsia?

OBJECTIVE

To evaluate the levels of serum beta-2-glycoprotein I (β₂GP1) and clusterin in the duality of Pre-eclampsia and HIV.

METHOD

Stored serum samples collected from 72 pregnant women were stratified according to the pregnancy type (pre-eclamptic and healthy normotensive groups) and HIV status (positive or negative). A Bio-Plex multiplex immunoassay was used to determine the concentrations of clusterin and β₂GP1.

RESULTS

Clusterin concentrations differed significantly (p = 0.01) between the HIV positive (+) (mean = 123 800 ng/ml; 95 % CI: 105 400-142 200) vs. HIV negative (-) (mean = 92 190 ng /ml; 95 %CI: 75 840-108 500) groups and across all groups (p = 0.0006). Beta-2-glycoprotein I concentration differed significantly based on HIV status (p < 0.0001); HIV+ (mean = 393 649 ng/ml; 95 %CI: 30 300-467 000) vs HIV- (mean = 224 309 ng/ml; 95 %CI: 154 000-294 700) and across all groups (p < 0.0001). No significant difference was observed between normotensive and Pre-eclamptic groups for both clusterin and β₂GPI.

CONCLUSION

Serum concentrations of clusterin and β₂GPI were significantly increased in HIV positive pregnancies. It is postulated that both clusterin and β₂GPI may have a role in HIV disease progression. These findings need to be confirmed in studies having larger sample sizes and detailed information on anti-retroviral therapy.

Managing pregnancy-associated clinical emergencies in systemic lupus erythematosus: a case-based approach

Introduction: Systemic lupus erythematosus (SLE)-related thrombocytopenia during pregnancy and the postpartum period have been associated with adverse pregnancy outcomes and perinatal complications. In this case report, we present two SLE patients with thrombocytopenia emergencies secondary to HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome and thrombotic thrombocytopenic purpura (TTP).Areas covered: The first case involved a 26-year-old woman, G1P0 at 26 weeks gestation (GA), with high-titer antiphospholipid antibodies (aPL) (positive lupus anticoagulant, anti-beta 2 glycoprotein-1 (aβ2GP1), anti-cardiolipin) and non-criteria aPL to phosphatidylserine/prothrombin complex and anti-domain 1 β2GP1. This case highlights the risks associated with aPL in pregnancy, considers management issues relating to anticoagulation during pregnancy and highlights the importance of maintaining a high index of suspicion for diagnosis of HELLP in SLE patients. The second case was a 36-year-old female, G3P2 at 32 weeks GA, with class III lupus nephritis (LN) who developed severe pre-eclampsia, which included mild thrombocytopenia. This case illustrates the challenges in identifying and differentiating between three pregnancy emergencies that can be seen in SLE patients (pre-eclampsia, LN, and TTP) and presents the management of TTP in peripartum SLE.Expert opinion: These two cases remind us of the importance of timely diagnosis and management of thrombocytopenia in this population.

Characteristics of pregnancy complications and treatment in obstetric antiphospholipid syndrome in China

OBJECTIVES

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by obstetric complications and thrombotic events associated with antiphospholipid antibodies (aPL). We aimed to compare the clinical characteristics and treatment of primary APS (PAPS) and secondary APS (systemic lupus erythematosus-APS, SAPS) patients and investigate risk factors associated with obstetric complications in Shanghai, China.

METHODS

We retrospectively collected and analyzed the data of obstetric APS (OAPS) patients from 2000 to 2017 in the APS-Shanghai (APS-SH) database.

RESULTS

One hundred eighty OAPS patients with a total of 450 pregnancies were included in this study. Two hundred twenty-one (49.11%) pregnancies resulted in miscarriage, and 161 (35.77%) pregnancies resulted in intrauterine death. In our cohort, when women were treated, 57 out of 66 pregnancies resulted in live births (86%). Of the 9 treated patients who failed to have live births, 3 had intrauterine deaths, 3 had fetal growth restriction, 2 had pneumorrhagia of the newborn, and 1 had a miscarriage. OAPS patients were divided into two groups: PAPS and SAPS. More SAPS patients than PAPS patients used glucocorticoids (GCs) and hydroxychloroquine (both p < 0.001). However, there was no significant difference in the GC dosage between SAPS and PAPS patients (p = 0.188). Lupus anticoagulant (LAC) and IgG aβ2GPI were risk factors for miscarriage (odds ratio (OR) = 2.398, 95% confidence interval (CI) = 1.276-4.505, p = 0.002; OR = 2.907, 95% CI = 1.558-5.405, p = 0.001, respectively) and intrauterine death (OR = 2.439, 95% CI = 1.299-4.580, p = 0.006; OR = 2.060, 95% CI = 1.089-3.897, p = 0.026, respectively).

CONCLUSIONS

The live birth rate of OAPS patients in Shanghai was 86%. Even if OAPS patients were treated, pregnancy complications could occur, and these patients might need further second-line treatment. Key Points • This is the first study to report data on Chinese OAPS patients. The live birth rate was 86%. • Lupus anticoagulant and IgG aβ2GPI were risk factors for miscarriage and intrauterine death in our cohort. • Despite active treatment, 9 patients had obstetric complications. Therefore, further second-line treatment is still needed.

Complement in the Pathophysiology of the Antiphospholipid Syndrome

The antiphospholipid syndrome (APS) is characterized by thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). Complement is a system of enzymes and regulatory proteins of the innate immune system that plays a key role in the inflammatory response to pathogenic stimuli. The complement and coagulation pathways are closely linked, and expanding data indicate that complement may be activated in patients with aPL and function as a cofactor in the pathogenesis of aPL-associated clinical events. Complement activation by aPL generates C5a, which induces neutrophil tissue factor-dependent procoagulant activity. Beta-2-glycoprotein I, the primary antigen for pathogenic aPL, has complement regulatory effects in vitro. Moreover, aPL induce fetal loss in wild-type mice but not in mice deficient in specific complement components (C3, C5). Antiphospholipid antibodies also induce thrombosis in wild type mice and this effect is attenuated in C3 or C6 deficient mice, or in the presence of a C5 inhibitor. Increased levels of complement activation products have been demonstrated in sera of patients with aPL, though the association with clinical events remains unclear. Eculizumab, a terminal complement inhibitor, has successfully been used to treat catastrophic APS and prevent APS-related thrombotic microangiopathy in the setting of renal transplant. However, the mechanisms of complement activation in APS, its role in the pathogenesis of aPL related complications in humans, and the potential of complement inhibition as a therapeutic target in APS require further study.

First-Line, Non-Criterial Antiphospholipid Antibody Testing for the Diagnosis of Antiphospholipid Syndrome in Clinical Practice: A Combination of Anti-β2 -Glycoprotein I Domain I and Anti-Phosphatidylserine/Prothrombin Complex Antibodies Tests

OBJECTIVE

To assess the value of a combination of anti-β₂ -glycoprotein I (anti-β₂ GPI) domain I antibody and anti-phosphatidylserine/prothrombin complex (anti-PS/PT) antibody tests for the diagnosis of antiphospholipid syndrome (APS).

METHODS

This cross-sectional study involved a cohort of the patients who visited our clinic from April 2005 to March 2013. Tests for anti-β₂ GPI domain I antibodies, IgG anti-PS/PT antibodies, and IgM anti-PS/PT antibodies, together with tests for criteria-defined antiphospholipid antibodies (aPL), were performed in all patients. The total antiphospholipid score (aPL-S) was calculated for each patient according to titers of and positivity for aPL.

RESULTS

The study enrolled 157 patients (51 patients with APS and 106 with non-APS autoimmune diseases). All 21 patients positive for both anti-β₂ GPI domain I antibodies and IgG and/or IgM (IgG/IgM) anti-PS/PT antibodies had APS with a high total aPL-S (median 46, range 26-76), as did all of the 10 patients who were positive for anti-β₂ GPI domain I antibodies but negative for IgG/IgM anti-PS/PT antibodies (median 22, range 4-39). Of the 14 patients who were positive for IgG/IgM anti-PS/PT antibodies but negative for anti-β₂ GPI domain I antibodies, 11 (79%) had APS; these individuals also had high total aPL-S values (median 23, range 11-60). In contrast, only 9 of the 112 patients (8%) with none of these antibodies had APS.

CONCLUSION

The combination of the IgG anti-β₂ GPI domain I antibody and IgG/IgM anti-PS/PT antibody tests shows a high positive predictive value for the diagnosis of APS and a strong correlation with the aPL-S. This combination as the first-line test for aPL may contribute to the simple and definite identification of APS with a high risk of thrombosis in clinical practice.

Severe Preeclampsia, Antiphospholipid Syndrome, and Ulnar Artery Thrombosis in a Teenage Pregnancy: A Rare Association

Antiphospholipid syndrome (APS) is associated with vascular thrombosis and pregnancy complications. It causes recurrent miscarriage and it is associated with other adverse pregnancy outcomes such as preterm delivery, intrauterine growth restriction, preeclampsia, and HELLP syndrome. Obstetric morbidity is one of the major manifestations of APS with a wide variety of clinical manifestations. This case describes a case of a severe preeclampsia in a 16-year-old primigravida at 29 weeks resulting in a caesarean delivery and subsequent finding of an ulnar artery thrombosis in postpartum period. APS was diagnosed on further investigations of her symptoms and signs.

The clinical value of assays detecting antibodies against domain I of β2-glycoprotein I in the antiphospholipid syndrome

As the clinical symptoms of the antiphospholipid syndrome (APS) frequently occur irrespective of the syndrome, diagnosis predominantly depends on the laboratory assays measuring the level or function of antiphospholipid antibodies (aPLs). β2-glycoprotein I (β2GPI) is increasingly accepted as the most important target of aPLs. Anti-β2GPI antibodies constitute a heterogeneous population, but current in vivo and in vitro evidence show that especially the first domain (DI) of β2GPI contains an important pathogenic epitope. This epitope containing Glycine40-Arginine43 (G40-R43) has proven to be cryptic and only exposed when β2GPI is in its open conformation. A previous study demonstrated a highly variable exposure of the cryptic epitope in commercial anti-β2GPI assays, with implications on correct patient classification. Unexpectedly, recent unpublished data revealed impaired exposure of the pathogenic epitope in the commercially available anti-DI chemiluminescence immunoassay (CIA) assay detecting specific antibodies directed to DI. In this review we summarize the laboratory and clinical performance characteristics of the different anti-DI assays in published data and conclude with inconsistent results for both the correlation of anti-DI antibodies with clinical symptoms and the added value of anti-DI antibodies in the classification criteria of APS. Additionally, we hypothesize on possible explanations for the observed discrepancies. Finally, we highly advise manufacturers to use normal pooled plasma spiked with the monoclonal anti-DI antibodies to verify correct exposure of the cryptic epitope.

Prevalence, persistence and clinical correlations of classic and novel antiphospholipid antibodies in systemic lupus erythematosus

Objectives

aPL are frequently present in SLE. In a well characterized SLE cohort we aimed at investigating the prevalence of aPL and assessing their analytical performance and clinical association by testing criteria specificities including LA, aCL IgG and IgM, anti-β2-glycoprotein 1 (antiβ2GP1) IgG and IgM, as well as the non-criteria aPS-PT IgG and IgM and anti-β2GP1 domain 1 (aD1) IgG.

Methods

We included 178 patients satisfying the ACR SLE classification criteria, from whom 283 samples and thrombotic events were collected longitudinally. Each sample was tested for criteria and non-criteria aPL using validated techniques in a single centre.

Results

All assays provided highly reproducible results. Of the samples, 42.5% were positive for at least one criteria assay, 20.5% showed double positivity and 12.6% triple positivity. All criteria and non-criteria specificities persisted over time. Most antibody titres were only moderately correlated; however, strong correlation was observed on one hand between aD1 IgG, antiβ2GP1 IgG and aCL IgG, and on the other between aPS-PT IgG and LA. aD1 IgG titres were extremely elevated in triple-positive samples. aPS-PT IgG by itself, and jointly with LA, was associated with thrombosis, an association mostly driven by venous thrombotic events.

Conclusions

In this SLE cohort, the non-criteria aPL aD1 IgG and aPS-PT IgG performed differently. aD1 IgG was highly enriched in triple-positive samples, and aPS-PT IgG, jointly with LA, was associated with thrombotic events.

Antiphosphatidylserine/prothrombin Antibodies in Antiphospholipid Syndrome with Intrauterine Growth Restriction and Preeclampsia

OBJECTIVE

Antibodies that recognize the phosphatidylserine/prothrombin complex (antiphosphatidylserine/prothrombin antibodies; aPS/PT) might reveal enhanced thrombotic risk in patients with systemic lupus erythematosus. Little is known about their association with pregnancy complications in the antiphospholipid syndrome (APS).

METHODS

We enrolled 55 patients with APS who were seeking pregnancy in 2 Italian hospitals. Antiphospholipid antibodies (aPL), including anticardiolipin antibodies, anti-β₂-glycoprotein I antibodies, lupus-like anticoagulant, and aPS/PT antibodies were assessed, and the patients were prospectively followed for 24 months.

RESULTS

There were 65% (36/55) of the APS patients who had aPS/PT antibodies. Forty-seven pregnancies were followed, including 33 of aPS/PT+ patients. Forty-one of the 47 patients (87%) who initiated a pregnancy eventually gave birth to a child. The pregnancy duration and the mean newborn weight at delivery were significantly lower in aPS/PT+ than in aPS/PT- patients (33.1 ± 4.7 vs 36.2 ± 3.4 wks of gestation, respectively, and 2058 ± 964 g vs 2784 ± 746 g, respectively, p < 0.05). Late pregnancy complications, including intrauterine fetal death, preterm delivery, preeclampsia, and intrauterine growth restriction (IUGR), were more frequent in aPS/PT+ patients, independent of the therapy. Titers of aPS/PT IgG were significantly inversely correlated with the neonatal weight at delivery. Vascular injury, as reflected by thrombosis, fibrinoid necrosis, ischemic and hemorrhagic areas, and presence of chorangiomas characterized the IUGR placentas in the presence of aPS/PT.

CONCLUSION

The aPS/PT antibodies might represent markers of aPL-related pregnancy complications, IUGR/preeclampsia in particular, and could help identify beforehand patients who may require additional treatment.

Antiphospholid antibodies and the risk of pregnancy complications

Antiphospholipid antibodies (APLAbs) are generally considered as risk factors for foetal death, for premature birth ≤34weeks due to severe pre-eclampsia or severe placental insufficiency and for recurrent consecutive spontaneous abortions <10weeks. Among these three obstetrical morbidities, only the first one is however not regularly questioned. The coexistence of an inflammatory disease and/or of thrombotic manifestations increases the obstetrical risks. Among the three criteria APLAbs, i.e. lupus anticoagulant (LA), anticardiolipin (aCL) Abs, anti-β2 glycoprotein-I (aβ2GP1)Abs, LA seems the more widely associated to clinical risks, the clinical impact of aβ2GP1Abs is progressively defined and the pejorative impact of triple positivity is still discussed. High quality prospective multicentric epidemiological studies are still awaited. The identification of predictors of pregnancy outcome is necessary to streamline the design and use of new treatments acting on pathophysiological molecular targets.

Anticoagulants to prevent recurrent placenta-mediated pregnancy complications: Is it time to put the needles away?

Placenta-mediated pregnancy complications, such as pre-eclampsia, placental abruption, birth of a small-for-gestational age infant and late pregnancy loss, are common and carry significant morbidity and mortality. The etiology of placenta-mediated pregnancy complications is likely multifactorial and may include abnormal coagulation activation of the maternal-fetal interface. The use of antepartum low-molecular-weight heparin (LMWH) prophylaxis to prevent recurrent placenta-mediated pregnancy complications has become common practice despite limited and conflicting evidence to support its use. This paper reviews the evidence, including recently published data from an individual patient level meta-analysis, which challenges the role of LMWH in preventing recurrent placenta-mediated pregnancy complications. Incorporating this recent evidence, we recommend against the use of LMWH to prevent recurrent placenta-mediated pregnancy complications in women with and without inherited thrombophilia.

Metabolic abnormalities and obesity's impact on the risk for developing preeclampsia

Preeclampsia (PE), a hypertensive disorder of pregnancy, is increasing as a major contributor to perinatal and long-term morbidity of mother and offspring. PE is thought to originate from ischemic insults in the placenta driving the release of prohypertensive anti-angiogenic [soluble fms-like tyrosine kinase-1 (sFlt-1)] and proinflammatory [tumor necrosis factor-α (TNF-α)] factors into the maternal circulation. Whereas the increased incidence of PE is hypothesized to be largely due to the obesity pandemic, the mechanisms whereby obesity increases this risk are unknown. The maternal endothelium is targeted by placental and adipose tissue-derived factors like sFlt-1 and TNF-α that promote hypertension during pregnancy, resulting in vascular dysfunction and hypertension. Interestingly, not all obese pregnant women develop PE. Data suggest that obese pregnant women with the greatest metabolic abnormalities have the highest incidence of PE. Identifying obesity-related mechanisms driving hypertension in some obese pregnant women and pathways that protect normotensive obese pregnant women, may uncover novel protocols to treat PE. Metabolic abnormalities, such as increased circulating leptin, glucose, insulin, and lipids, are likely to increase the risk for PE in obese women. It is not only important to understand whether each of these metabolic factors contribute to the increased risk for PE in obesity, but also their cumulative effects. This is particularly relevant to obese pregnant women with gestational diabetes mellitus (GDM) where all of these factors are increased and the risk for PE is highest. It is speculated that these factors potentiate the anti-angiogenic and proinflammatory mechanisms of placental ischemia-induced vascular dysfunction thereby contributing to the increasing incidence of PE.