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-ß2 glycoprotein-I (aß2GP1)Abs, LA seems the more widely associated to clinical risks, the clinical impact of aß2GP1Abs 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.

Isotypic analysis of antibodies against activated Factor VII in patients with Factor VII deficiency using the x-MAP technology.

While the immune response to hemophilic factors in hemophilia has been widely studied, little is known about the development of anti-Factor VII (FVII) antibodies in FVII deficiency. We developed a robust technique based on the x-MAP technology to detect the presence of antibodies against FVII and characterize their isotype and validated this method using blood samples from 100 patients with FVII deficiency (median FVII clotting activity [FVII:C]: 6%) and 95 healthy controls. Anti-FVII antibodies were detected in patients but also in some controls, although the concentration of total immunoglobulin G (IgGt) and IgG1 and IgG4 subclasses was significantly different between groups. The IgG1 subclass concentrations remained significantly different also when only untreated patients were compared with controls. This difference could partially be related to the F7 genotype, particularly in patients harboring the p.Arg139Gln mutation. This x-MAP-based method might be useful for assessing the immunogenicity of novel FVII compounds and of activated FVII (FVIIa) concentrates. Further prospective studies are needed to better understand the clinical relevance of these antibodies in the management of patients with FVII deficiency.

The A6936G polymorphism of the endothelial protein C receptor gene is associated with the risk of unexplained foetal loss in Mediterranean European couples.

The endothelial protein C receptor (EPCR) is expressed by trophoblast cells. Mid-gestation pregnancy loss is described in animals with a haemochorial placenta lacking EPCR. The A6936G allele of the EPCR gene (PROCR) may be associated with lower EPCR densities on trophoblasts, but data are lacking for its effect on the risk of pregnancy loss in humans. A 1:2 case-control study on unexplained pregnancy loss was nested in the NOHA First cohort: 3,218 case couples and 6,436 control couples were studied for PROCR A6936G, coagulation factor V gene (F5) G1691A and coagulation factor II gene (F2) G20210A polymorphisms. Ethnicity and time of pregnancy loss defined through biometry-based gestational ages (embryonic loss < 10(th) week > or = foetal loss) were analysed. The PROCR A6936G allele, in mothers and fathers, was associated only with foetal loss in both Europeans and non-Europeans. Increasing probability levels of carrying a homozygous child were increasingly associated with the risk of foetal demise. The F5 G1691A and F2 G20210A alleles, only in mothers, were only and independently associated with foetal loss in Europeans. In our population, the PROCR A6936G allele describes women, but also men and thus couples, at risk for first unexplained foetal loss. This risk is independent of the foetal loss risk conferred to our local Mediterranean European women by the F5 G1691A and F2 G20210A alleles. Data confirm that the relationship between thrombophilias and pregnancy loss varies according to ethnicity and loss type.

Analysis of the venous thromboembolic risk associated with severe postpartum haemorrhage in the NOHA First cohort.

Severe postpartum haemorrhages (PPH) are responsible for maternal morbidity/mortality. Their complex management sometimes requires haemostatic supplementation, and therapeutic trials on fibrinogen or activated factor VII, which may add to the thrombotic risk, are currently being considered. Furthermore, there is a risk of venous thromboembolism (VTE) during the postpartum period, hence we studied the relationship between severe PPH and VTE in women during their first pregnancy. Among the 32,463 women enrolled between January 1, 1999 and February 1, 2004 in the NOHA First cohort, 317 developed severe PPH, 11 postpartum VTE and 60 had postpartum superficial vein thrombosis (SVT). In the women with severe PPH, whilst there were no episodes of VTE, there were three episodes of SVT, which occurred 6 weeks postpartum. All of the women with severe PPH received packed red blood cell (RBC) units, 29 (9.1%) platelets units, 51 (16.1%) fresh frozen plasma and 29 (9.1%) fibrinogen concentrates. Three patients with both severe PPH and SVT received only packed RBC. Severe PPH or packed RBC unit transfusion were associated with postpartum SVT (adjusted relative risk: 5.3 (1.6-17) and 4.7 (1.5-15) respectively), independent of caesarean section delivery and low-molecular-weight heparin (LMWH) use in the postpartum, but were not independent indicators of one another. This the VTE and SVT risks associated with severe PPH are low (<1% and <2%, respectively). Severe PPH increases the risk of postpartum SVT, but transfusion with platelet units and plasma supplementation using fresh frozen plasma or fibrinogen concentrates do not markedly modulate the risk of venous thrombosis.

Monitoring the effects and managing the side effects of anticoagulation during pregnancy.

LMWHs are the major anticoagulant/antithrombotic treatment given to pregnant women to prevent and treat venous thromboembolism despite the absence of specific clinical trials. An emerging indication, the prevention of adverse pregnancy outcomes, is under investigation. During pregnancy, LMWHs seem to be safe and efficient. Some uncertainties remain about the management of rare potential side effects, particularly in the event of heparin intolerance and with cross-reactivity to danaparoid sodium.

Prophylaxis and treatment of thrombophilia in pregnancy.

PURPOSE OF REVIEW: This review addresses the prophylaxis and treatment of thrombophilia in pregnancy, which is associated with increased risk of venous thromboembolism and placental vascular complications. RECENT FINDINGS: Topics include preventing deep vein thrombosis recurrence in pregnant women with constitutional thrombophilias, using prophylactic heparins throughout pregnancy and postpartum anticoagulants. Cases of thrombosis still occur in the postpartum period and other therapeutics should be tested. Primary prophylaxis is acceptable for high-risk thrombophilias. Early pregnancy losses (before the 10th week) are not associated with constitutional thrombophilias. The natural prognosis of embryonic losses associated with current thrombogenic polymorphisms is good, unlike fetal losses associated with the same thrombophilias: in this case, a prophylactic low-molecular-weight heparin given from the beginning of the 8th week is more efficient than low-dose aspirin. Data are lacking on the prevention of severe preeclampsia, placental abruption, or intrauterine growth restriction in women with constitutional thrombophilias; preliminary results indicate that low-molecular-weight heparin may have some preventive effect. Specific studies are needed. SUMMARY: Recent studies have shown the limits of available procedures for women with constitutional thrombophilia and have helped define the clinical situations in thrombophilia-related placental insufficiency in which prophylactic low-molecular-weight heparin may be indicated.

The association between hereditary thrombophilias and pregnancy loss.

The correlation between hereditary thrombophilia and fetal loss is supported by several observations. In murine models, the protein C system has been shown to be essential for the maintenance of pregnancy, as it indirectly acts as a growth factor for trophoblast cells and protects them from apoptosis. In humans, it has been shown that the placenta replaces the yolk sac as an essential source of blood supply to the embryo during the 8th and 9th weeks of gestation. Furthermore, meta-analysis of epidemiological data demonstrates a correlation between thrombophilic polymorphisms such as factor V Leiden and prothrombin 20210G-->A and isolated or recurrent fetal losses. Finally, therapeutic non-controlled trials indicate the benefits and safety of low-molecular weight heparins as secondary prophylaxis. However, it is still necessary to further clarify the association between thrombophilia and fetal loss, especially during a first pregnancy, with regard to the type of pregnancy loss and with respect to other related factors.