Factor XII but not protein C, protein S, antithrombin III, or factor XIII is a predictor of recurrent miscarriage

Investigating the predictive role of serum amyloid A and its association with immunological and coagulation biomarkers in recurrent pregnancy loss

To evaluate the predictive role of serum amyloid A (SAA) levels and their association with antiphospholipid antibodies (APA) and coagulation markers such as lupus anticoagulants (LA), anti-cardiolipin (ACA), protein C (PC) deficiency, protein S (PS) deficiency, and antithrombin III (ATIII) deficiency in recurrent pregnancy loss (RPL). This prospective case-control study comprised two groups: the study group (n = 88) included women with recurrent pregnancy loss at Mansoura University Hospital between January 2019 and December 2020, and the control group (n = 52) included women without obstetric or medical complications. Demographic, clinical, and laboratory data, including serum samples collected at 10 weeks of gestation, were collected from all participants. The study measured SAA levels, lupus anticoagulants, anti-cardiolipin, protein C, protein S, and antithrombin III levels. The SAA level was significantly elevated in the recurrent pregnancy loss group compared to that in the control group. Lupus anticoagulant positive, anti-cardiolipin positive Immunoglobulin M (IgM), and deficiencies in protein C, protein S, and antithrombin III were significantly observed in patients with RPL (p < 0.05). The SAA levels were significantly elevated in both LA-positive and ACA-positive IgM patients. The receiver operating characteristic (ROC) curve analysis demonstrated that at SAA > 24.8 for the prediction of recurrent pregnancy loss, sensitivity was 98.86%, and specificity was 92.31%. Positive and negative predictive values were 95.6% and 98.0%, respectively. The area under the curve = 0.971 (0.927-0.992). SAA is associated with recurrent pregnancy loss and may therefore serve as a potential predictor of this condition. The observed elevation in SAA levels could be primary or secondary to the inflammatory response that promotes thrombotic activity in RPL patients at risk of APA, Protein S, Protein C, and ATIII deficiencies. Implementing SAA screening during pregnancy may facilitate the identification of individuals who could potentially benefit from novel treatment strategies.

Thrombosis-related characteristics of pregnant women with antithrombin deficiency, protein C deficiency and protein S deficiency in Japan

BACKGROUND

 We previously conducted a primary survey of pregnant women with hereditary thrombophilia based on national surveillance in Japan, but did not examine their thrombosis-related characteristics. Antithrombin (AT) deficiency, protein C (PC) deficiency and protein S (PS) deficiency are the major types of hereditary thrombophilia in Japan.

METHODS

We examined their detailed information related to thrombosis, and evaluated peripartum outcomes in comparison with control data obtained from the Japan Society of Obstetrics and Gynecology.

RESULTS

Definite or probable AT deficiency, PC deficiency and PS deficiency were observed in 80, 50, and 317 pregnancies, respectively, from 2014 to 2018 in Japan, with prevalence rates among total deliveries of 0.011%, 0.007%, 0.044%. The number of pregnancies with AT, PC and PS deficiency might have been as many as 27, 17 and 108 every year if complete answers had been provided. In the peripartum period of current pregnancies, 27.5% of women with AT deficiency, 28.0% with PC deficiency and 13.2% with PS deficiency developed thrombosis (p < 0.001 vs. control). Pregnant women with AT and PC deficiency were more susceptible to thrombosis than those with PS deficiency (P < 0.01). Of the thromboses, 92.3% occurred during pregnancy, 62.8% at less than 15 gestational weeks. The earliest onset of thrombosis was 5 gestational weeks. Prophylactic anticoagulation significantly prevented the onset of both antepartum and postpartum thrombosis (p < 0.0001). The rate of recurrent pregnancy loss in women with low PC or PS activities was significantly higher than in controls (p < 0.0001); however, it is unknown whether recurrent pregnancy loss is related to hereditary PS deficiency. There seem to have been few serious maternal or fetal/neonatal complications due to placental insufficiency related to a hypercoagulable state other than growth restriction.

CONCLUSIONS

This survey revealed the thrombosis-related characteristics of pregnant women with hereditary thrombophilia in Japan. We suggest prophylactic anticoagulation to prevent maternal or fetal/neonatal complications.

Platelet and Thrombophilia-Related Risk Factors of Retinal Vein Occlusion

Retinal vein occlusion (RVO) is a heterogenous disorder in which the formation of a thrombus results in the retinal venous system narrowing and obstructing venous return from the retinal circulation. The pathogenesis of RVO remains uncertain, but it is believed to be multifactorial and to depend on both local and systemic factors, which can be divided into vascular, platelet, and hypercoagulable factors. The vascular factors include dyslipidaemia, high blood pressure, and diabetes mellitus. Regarding the platelet factors, platelet function, mean platelet volume (MPV), platelet distribution width (PDW), and platelet large cell ratio (PLCR) play key roles in the diagnosis of retinal vein occlusion and should be monitored. Nevertheless, the role of a hypercoagulable state in retinal vein occlusion remains unclear and requires further studies. Therefore, the following article will present the risk factors of RVO associated with coagulation disorders, as well as the acquired and genetic risk factors of thrombophilia. According to Virchow’s triad, all factors mentioned above lead to thrombus formation, which causes pathophysiological changes inside venous vessels in the fundus of the eye, which in turn results in the vessel occlusion. Therefore, a diagnosis of retinal vein occlusion should be based on both eye examination and general examination, including laboratory tests.

Clinical guidance for peripartum management of patients with hereditary thrombophilia

Hereditary thrombophilia is a condition in which individuals are susceptible to the formation of thrombi due to a hereditary deficiency in anticoagulant factors, antithrombin (AT), protein C (PC), or protein S (PS). Many Japanese thrombophilia patients have PS deficiency, especially PS p.K196E (also called as PS Tokushima), which is exclusive to the Japanese population, and thrombosis sometimes occurs during pregnancy. At present, no management guidelines for pregnancy and delivery in thrombophilia patients have been developed. The Study Group for Hereditary Thrombophilia, one of the research groups of blood coagulation abnormalities in the Research Program on Rare and Intractable Diseases supported with the Research Grants of the Ministry of Health, Labour and Welfare Science, has therefore developed this clinical guidance to provide healthcare workers with necessary information on safe pregnancy, parturition and neonatal management, adopting a format of responses to seven clinical questions (CQ). At the end of each answer, the corresponding Recommendation Level (A, B, C) is indicated.

Factor XIII-A: An Indispensable "Factor" in Haemostasis and Wound Healing

Factor XIII (FXIII) is a transglutaminase enzyme that catalyses the formation of ε-(γ-glutamyl)lysyl isopeptide bonds into protein substrates. The plasma form, FXIIIA₂B₂, has an established function in haemostasis, with fibrin being its principal substrate. A deficiency in FXIII manifests as a severe bleeding diathesis emphasising its crucial role in this pathway. The FXIII-A gene (F13A1) is expressed in cells of bone marrow and mesenchymal lineage. The cellular form, a homodimer of the A subunits denoted FXIII-A, was perceived to remain intracellular, due to the lack of a classical signal peptide for its release. It is now apparent that FXIII-A can be externalised from cells, by an as yet unknown mechanism. Thus, three pools of FXIII-A exist within the circulation: plasma where it circulates in complex with the inhibitory FXIII-B subunits, and the cellular form encased within platelets and monocytes/macrophages. The abundance of this transglutaminase in different forms and locations in the vasculature reflect the complex and crucial roles of this enzyme in physiological processes. Herein, we examine the significance of these pools of FXIII-A in different settings and the evidence to date to support their function in haemostasis and wound healing.

Uneventful delivery of two pregnancies in a woman with severe factor XII deficiency: case report and systematic review

Background

Deficiency of factor XII (FXII) is widely considered to have a detrimental effect on pregnancy. Several reports underline the increased risk for antenatal complications with few published case reports of uncomplicated deliveries. The main objective of our article is to perform a systematic review to highlight pregnancies with severe deficiency of FXII that have been delivered uneventfully, along with presenting our relative case of a woman with severe deficiency of FXII.

Materials and methods

A systematic review was performed in the Pubmed database. Inclusion criteria were considered to be case reports and case series presenting delivery of uncomplicated pregnancies in women with severe FXII deficiency. Medical records of our patient were also reviewed in terms of signs and symptoms, laboratory and imaging examinations and neonatal outcomes.

Results

There were 62 abstracts derived while 44 were assessed for eligibility. There were finally three case reports of women with FXII deficiency delivering live newborns and one case series of 12 women with a final outcome of 19 deliveries. Regarding our case presentation, the woman with FXII levels <12%, after a neonatal death because of extreme prematurity (24 weeks + 4 days), was set in regular follow-up and treatment with bemiparin natriate, 3.5 mg/kg and acetylsalicylic acid, 100 mg/day. She finally managed to have her second pregnancy delivered at 38 weeks + 3 days, her third pregnancy ended up as a miscarriage and her fourth pregnancy was also delivered at 37 weeks + 4 days.

Conclusion

Despite the increased risk for antenatal complications, appropriate follow-up of pregnancies with severe FXII pregnancy may finally lead to an uneventful delivery.

Advances of Coagulation Factor XIII

Objective:

To provide a comprehensive literature review on roles of coagulation factor XIII (FXIII) in coagulation, wound healing, neoplasm, bone metabolism, and pregnancy.

Data Sources:

All articles in PubMed with key words Coagulation factor XIII, wound, leukemia, tumor, bone, and pregnancy with published date from 2001 to 2016 were included in the study. Frequently cited publications before 2000 were also included.

Study Selection:

We reviewed the role of FXIII in biologic processes as documented in clinical, animal, and in vitro studies.

Results:

FXIII, a member of the transglutaminase (TG) family, plays key roles in various biological processes. Besides its well-known function in coagulation, the cross-linking of small molecules catalyzed by FXIII has been found in studies to help promote wound healing, improve bone metabolism, and prevent miscarriages. The study has also shown that FXIII concentration level differs in the blood of patients with leukemia and solid tumors and offers promises as a diagnostic indicator.

Conclusions:

FXIII has many more biologic functions besides being known as coagulation factor. The TG activity of FXIII contributes to several processes, including wound healing, bone extracellular matrix stabilization, and the interaction between embryo and decidua of uterus. Further research is needed to elucidate the link between FXIII and leukemia and solid tumors.

Management of recurrent miscarriage

Recurrent miscarriage is classically defined as three or more consecutive pregnancy losses. Many researchers have now revised this definition to two or more pregnancy losses because of the recent increase in the prevalence of childless couples. Established causes of recurrent miscarriage are antiphospholipid antibodies, uterine anomalies and abnormal chromosomes in either partner, particularly translocations. Antiphospholipid syndrome is the most important treatable cause of recurrent miscarriage. However, it is not yet established as to what kind of testing should be conducted in patients with recurrent pregnancy loss. Standardization of tests for antiphospholipid antibodies is needed. On the other hand, embryonic aneuploidy is the most frequent cause of recurrent miscarriage. Chromosome analysis of the embryo is important, because it has good predictive value for subsequent live birth. It is not necessary to give any medications for unexplained cases of recurrent miscarriage, and provision of psychological support may be the most important to encourage the couples to continue to conceive until a live birth results.

Genotyping analysis for the 46 C/T polymorphism of coagulation factor XII and the involvement of factor XII activity in patients with recurrent pregnancy loss

Background

Established causes of recurrent pregnancy loss (RPL) include antiphospholipid syndrome, uterine anomalies, parental chromosomal abnormalities, particularly translocations and abnormal embryonic karyotype. A systematic review concluded that coagulation factor XII (FXII) deficiency was associated with RPL. However, it could not be established whether the 46 C/T SNP of FXII or low activity of FXII was a risk factor for RPL, because of the small sample size.

Methods and Findings

We conducted a cross-sectional and cohort study in 279 patients with two or more unexplained consecutive pregnancy losses and 100 fertile women. The association between the lupus anticoagulant (LA) activity and FXII activity was examined. The frequency of the CC, CT and TT genotypes and the FXII activity were also compared between the patients and controls. Subsequent miscarriage rates among the CC, CT, TT genotypes and according to the FXII activity was examined. LA was associated with reduced FXII activity. The CT, but not the TT, genotype was confirmed to be a risk factor for RPL in the cross-sectional study using multivariate logistic regression analysis (OR, 2.8; 95% CI, 1.37–5.85). The plasma FXII activity in the patients was similar to that in the controls. Neither low FXII activity nor the CT genotype predicted the subsequent pregnancy outcome in the cohort study. On the other hand, and intermediate FXII activity level of 85–101% was predictive of subsequent miscarriage.

Conclusions

Low FXII activity was not associated with RPL. The FXII gene was found to be one of the significant susceptibility genes for RPL, similar to the FV Leiden mutation. However, the clinical influence of the CT genotype might be relatively small, because the presence/absence of this genotype did not have any predictive value for the subsequent pregnancy outcome. This was the first study indicating the influence of FXII 46C/T on further pregnancy outcomes.

Molecular Characterization of Cat Factor XII Gene and Identification of a Mutation Causing Factor XII Deficiency in a Domestic Shorthair Cat Colony

Coagulation factor XII (FXII) may be important in cardiovascular and inflammatory diseases. We have identified and characterized a naturally occurring mutation in the feline FXII gene that results in a mutant protein and enzymatic loss of activity. Feline intron/exon gene structure and sequence were acquired by comparing DNA sequences obtained from a fragmented Felis catus genomic sequence and the National Center for Biotechnology Information’s Cross Species Megablast of multiple species’ FXII gene sequences. Fourteen exons ranging in size from 57 to 222 base pairs were confirmed spanning 8 Kb on chromosome A1. The 1828–base pair feline FXII messenger RNA (mRNA) sequence contains an open reading frame that encodes a protein of 609 amino acids with high homology to human FXII protein. Total RNA and mRNA purified from liver tissue of 4 wild-type/normal and 8 FXII-deficient cats confirmed the predicted mRNA sequence and identified one important single-nucleotide polymorphism (SNP). A single base deletion in exon 11 of the FXII coding gene in our colony of cats results in deficient FXII activity. Translation of the mRNA transcript shows a frame shift at L441 (C441fsX119) resulting in a nonsense mutation and a premature stop codon with a predicted 560–amino acid protein. The mutant FXII protein is truncated in the 3′ proteolytic light chain region of the C-terminus, explaining its loss of enzymatic activity. This study is the first molecular characterization of the feline FXII gene and the first identification of an FXII mutation in the domestic cat, providing insights into the origin and nature of feline FXII deficiency.

New developments in the area of factor XIII

Coagulation factor (F)XIII is best known for its role in fibrin stabilization and cross-linking of antifibrinolytic proteins to the fibrin clot. From patients with congenital FXIII deficiency, it is known that FXIII also has important functions in wound healing and maintaining pregnancy. Over the last decade more and more research groups with different backgrounds have studied FXIII and have unveiled putative novel functions for FXIII. FXIII, with its unique role as a transglutaminase among the other serine protease coagulation factors, is now recognized as a multifunctional protein involved in regulatory mechanisms and construction and repair processes beyond hemostasis with possible implications in many areas of medicine. The aim of this review was to give an overview of exciting novel findings and to highlight the remarkable diversity of functions attributed to FXIII. Of course, more research into the underlying mechanisms and (patho-)physiological relevance of the many described functions of FXIII is needed. It will be exciting to observe future developments in this area and to see if and how these interesting findings may be translated into clinical practice in the future.

Factor XIII: a coagulation factor with multiple plasmatic and cellular functions

Factor XIII (FXIII) is unique among clotting factors for a number of reasons: 1) it is a protransglutaminase, which becomes activated in the last stage of coagulation; 2) it works on an insoluble substrate; 3) its potentially active subunit is also present in the cytoplasm of platelets, monocytes, monocyte-derived macrophages, dendritic cells, chondrocytes, osteoblasts, and osteocytes; and 4) in addition to its contribution to hemostasis, it has multiple extra- and intracellular functions. This review gives a general overview on the structure and activation of FXIII as well as on the biochemical function and downregulation of activated FXIII with emphasis on new developments in the last decade. New aspects of the traditional functions of FXIII, stabilization of fibrin clot, and protection of fibrin against fibrinolysis are summarized. The role of FXIII in maintaining pregnancy, its contribution to the wound healing process, and its proangiogenic function are reviewed in details. Special attention is given to new, less explored, but promising fields of FXIII research that include inhibition of vascular permeability, cardioprotection, and its role in cartilage and bone development. FXIII is also considered as an intracellular enzyme; a separate section is devoted to its intracellular activation, intracellular action, and involvement in platelet, monocyte/macrophage, and dendritic cell functions.

Diagnosis and treatment methods for recurrent miscarriage cases

Recurrent miscarriage is classically defined as three or more consecutive pregnancy losses. Established causes of recurrent miscarriage are antiphospholipid antibodies, uterine anomalies and abnormal chromosomes in either partner, particularly translocations. Embryonic aneuploidy is the most important cause of miscarriage before 10 weeks' gestation. It can be speculated that about 51% of patients with a history of three miscarriages experienced these because of abnormal embryonic karyotypes. It is not necessary to give any medication for such cases caused by an abnormal embryonic karyotype. Psychological tender loving care might be the most important requirement to continue conceiving till live birth results.

Factor XII gene expression in endometrial stromal cells during decidualisation

Decidualisation of endometrial stromal cells (ESC) is a prerequisite for the implantation of human embryos. Identification of genes that are upregulated or downregulated during decidualisation could lead to a better understanding of the molecular mechanisms involved in this process. In the present study, we examined differences in gene expression between decidualised and non-decidualised cells using microarray analysis and found that Factor XII (FXII) gene expression was upregulated during decidualisation. Furthermore, we also examined the expression of FXII by human ESC before and during pregnancy, as well as its expression by cells that had undergone decidualisation in vitro. Weak expression of FXII mRNA was detected in the non-pregnant endometrium that increased gradually from the proliferative to the secretory endometrium. During pregnancy, FXII mRNA expression was markedly increased in decidualised endometrium. When sex steroids (200 pg mL–1 of 17β-oestradiol and 100 ng mL–1 of progesterone) were used to induce in vitro decidualisation of ESC, the expression of FXII mRNA increased by approximately 25.3-fold compared with that in non-decidualised ESC. Using western blotting, we confirmed the presence of FXII protein (80 kDa) in ESC after in vitro decidualisation. Increased expression of FXII in ESC during decidualisation suggests that the kallikrein–kininogen–kinin system may be activated during the implantation of human embryos.

Anticoagulant therapy and pregnancy

Low dose aspirin therapy is one of the anticoagulant treatments used during pregnancy. Anticoagulant agents may be useful for several disorders, such as recurrent miscarriage, pre-eclampsia, fetal growth restriction and infertility. However, it is unclear whether anticoagulant therapy can increase the live birth rate in all of these cases. Recent data suggest that a low-dose aspirin and heparin combination therapy is effective in the prevention of recurrent pregnancy loss in women with antiphospholipid syndrome. Thrombogenic diseases, for example, protein C deficiency, protein S deficiency, factor XII deficiency and hyperhomocysteinemia, may cause pregnancy loss. The etiology of recurrent miscarriage is often unclear and may be multifactorial, with much controversy regarding diagnosis and treatment. Although 70% of recurrent pregnancy losses are unexplained, anticoagulant therapy is effective in maintaining pregnancy without antiphospholipid antibody syndrome. We conclude that a low-dose aspirin and heparin combination therapy can be useful for unexplained cases of recurrent pregnancy loss without antiphospholipid antibody syndrome. (Reprod Med Biol 2008; 7: 1-10).

Uterine Cervical Inflammatory Cytokines, Interleukin-6 and -8, as Predictors of Miscarriage in Recurrent Cases

PROBLEM

Inflammatory changes frequently occur in cases of second trimester miscarriage or pre-term delivery, but little attention has been paid to this association with recurrent miscarriage. As interleukin-6 and interleukin-8 are inflammatory cytokines reported to be associated with bacterial vaginosis, intrauterine infections, and pre-term delivery, we here investigated whether they might have predictive value for spontaneous abortion in recurrent cases.

METHOD OF STUDY

Cervical mucus and sera were collected at 4-5 weeks' gestation from a total of 59 patients with a history of two or more unexplained consecutive first trimester miscarriages, and examined by enzyme-linked immunosorbent assay. Patients then were followed up without medication and their pregnancy outcomes were compared with the test results.

RESULTS

Of a total of 59 patients, 13 (22%) miscarried subsequently. Both IL-6 and IL-8 in cervical mucus were significantly higher in patients who miscarried subsequently than in those who had a live birth. In addition, there was no correlation between cervical mucus and serum concentrations of IL-6 and IL-8 take at the same time, and there was no relation with serum IL-6 and IL-8 levels between the two groups.

CONCLUSION

Cervical IL-6 and IL-8 might have predictive value for cases of recurrent miscarriage.

Recurrent pregnancy loss: the key potential mechanisms

Recurrent pregnancy loss (RPL), which occurs in 0.5%-1% of total pregnancies, is usually defined as three or more consecutive spontaneous abortions before 20 weeks of gestation. Although an immunology-based etiology underlying unexplained RPL has been demonstrated, the exact molecular mechanisms are still poorly understood. Recent studies using transcriptomics and proteomics have implicated several factors. Here, we review the key possible mechanisms, in particular immunological abnormalities and thrombophilic aberration, that might underlie RPL. Taken together, these findings provide insight into the development of effective therapeutics for RPL.

Fibrinolytic defects and recurrent miscarriage: a systematic review and meta-analysis

OBJECTIVE

To systematically review evidence of the association between fibrinolytic defects and recurrent miscarriage.

DATA SOURCES

MEDLINE, EMBASE, and references of retrieved articles (last update September 2006) were used.

METHODS OF STUDY SELECTION

Studies comparing the prevalence of fibrinolytic defects in patients with recurrent miscarriage and control women were reviewed. Of 111 potentially relevant studies, data from 14 were integrated with meta-analytic techniques and were presented as odds ratios (ORs).

TABULATION, INTEGRATION, AND RESULTS

Plasminogen activator inhibitor-1 4G/5G polymorphism (OR 1.65, 95% confidence interval [CI] 0.92-2.95) and increased plasminogen activator inhibitor activity were not significantly associated with recurrent miscarriage, although the latter showed profound heterogeneity across studies. Although factor XII C46T polymorphism is not associated with recurrent miscarriage (OR 1.07, 95% CI 0.52-2.22), factor XII deficiency is significantly associated (five studies, 1,096 women; OR 18.11, 95% CI 5.52-59.39), with minimal heterogeneity across studies. Factor XIII Val34Leu and Tyr204Phe polymorphisms were not associated with recurrent miscarriage (OR 1.24, 95% CI 0.46-3.34 and OR 2.61, 95% CI 0.45-15.16, respectively). There were no eligible studies found for the rest of the factors searched (urokinase-type plasminogen activator, tissue-type plasminogen activator, kallicrein, a2-antiplasmin, a2-macroglobulin, thrombin-activated thrombolysis inhibitor, and factor XI). Only a small minority of studies ascertained miscarriage according to specific criteria, and none of the studies provided equal examination for confounders in cases and controls.

CONCLUSION

Factor XII deficiency is associated with recurrent miscarriage. Data on the other factors either fail to show association or are quite limited.

Prevalence of the coagulation factor XIII polymorphism Val34Leu in women with recurrent miscarriage

BACKGROUND

Recurrent miscarriage (RM) syndrome is not an uncommon obstetrical problem of multifactorial etiology. We investigated the role of the coagulation factor XIII (FXIII) Val34Leu polymorphism in RM.

METHODS

We recruited 80 subjects (40 normal and 40 with history of RM; of each group 20 pregnant and 20 non-pregnant) and analyzed the prevalence of this polymorphism. The women recruited for the present study had similar age and did not have history of any hemostatic disorders. FXIII levels and activity and the rate of fibrin cross-linking by FXIII genotype Val34Val and Val34Leu were studied.

RESULTS

Genotype analyses of patients and normal revealed that the frequencies distribution of Val/Val and Val/leu were statistically similar (P<0.05): 62.5% and 60%, and 37.5% and 40%, respectively; no Leu/leu genotype was found. The FXIII-A subunit levels and activity were also found similar between Val/Val and Val/leu genotypes in the different groups, pregnant and non-pregnant, normal or with RM. The rate of FXIII alpha and gamma-chains fibrin cross-linking was not different between the 2 genotypes.

CONCLUSION

From our results we conclude that FXIII Val34Leu polymorphism does not appear to be associated to RM.

Thrombophilia and Recurrent Pregnancy Loss

Many unanswered questions regarding thrombophilia and recurrent pregnancy loss exist. For example, does a true association exist? Are thrombotic mechanisms relevant? Is a second messenger necessary to cause the manifestation of thrombosis? At present it seems that thrombophilia are associated with and may even cause some cases of pregnancy loss. The role of treatment remains to be determined. Although the aim of physicians working in this field is entirely laudable, to allow childless couples to have children, it is necessary to have good evidence of effect before treatment is given to all patients. A serious ethical dilemma remains, however, namely should treatment that may be effective be denied to patients who have prior pregnancy losses? Denial of treatment is extremely distressing for the patient and the physician. The author's own practice is to offer treatment after a full explanation, particularly because treatment is generally prescribed in the antiphospholipid syndrome and justified in hereditary thrombophilias according to the report of Carp and colleagues, showing a 25% improvement in live birth rates in treated patients. When treatment fails, however, the embryo should be karyotyped to exclude chromosomal aberrations.

Complement as a predictor of further miscarriage in couples with recurrent miscarriages

BACKGROUND

The clinical significance of complement is unclear in patients with unexplained recurrent miscarriage, though low levels of complement 3 (C3) and/or complement 4 (C4) are reported to be associated with the antiphospholipid syndrome (aPS). We therefore investigated whether C3 and C4 have a predictive value for subsequent miscarriages.

METHODS

In total, 215 patients with a history of two consecutive first-trimester miscarriages and no abnormal chromosomes in either partner, no uterine anomalies and no antiphospholipid (aPL) antibodies were examined. Blood tests for C3, C4, total haemolytic complement (CH50), immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) were performed before subsequent pregnancy. Patients were then followed up without treatment, and their pregnancy outcomes were compared with their previous blood test results.

RESULTS

From 215 pregnant patients, 45 subsequently miscarried, whereas the remainder had a live birth. There was no relation with serum CH50, IgG, IgA and IgM levels, but C3 and C4 levels in patients with subsequent miscarriage were significantly higher than in those whose pregnancy was successful.

CONCLUSION

In patients with two previous miscarriages, C3 and C4 levels were higher in those women who had a third miscarriage, than in women that went on to have a live birth.

The C46T polymorphism of the coagulation factor XII gene and idiopathic recurrent miscarriage

Thrombophilia has been described to be involved in the pathogenesis of idiopathic recurrent miscarriage (IRM). We investigated the association between IRM and a C-->T polymorphism at nucleotide 46 in the 5'-untranslated region of the coagulation factor XII (FXII) gene. Two hundred and twelve women with a history of IRM and 149 healthy controls were tested by a mutagenically separated polymerase chain reaction assay (MS PCR). Allele and genotype frequencies were not significantly different between the study and the control groups. Our data suggest that the FXII gene is not a candidate gene for this condition.

An update in recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is defined as three or more consecutive pregnancy losses prior to the 20th week of gestation. The etiology of recurrent spontaneous abortion is often unclear and may be multifactorial, with much controversy regarding diagnosis and treatment. Reasonably accepted etiologic causes include, genetics, anatomical, endocrine, placental anomalies, hormonal problems, infection, smoking and alcohol consumption, exposure to environmental factors, psychological trauma and stressful life event, certain coagulation and immunoregulatory protein defects. Detection of an abnormality in any of these areas may result into specific therapeutic measures, with varying degrees of success. However, the majority of cases of RSA remains unexplained and is found to be associated with certain autoimmune (APA, ANA, ACA, ATA, AECA) and alloimmune (APCA, Ab2, MLR-Bf) antibodies that may play major role in the immunologic failure of pregnancy and may lead to abortion. Alteration in the expression of HLA-G molecules, T-helper-1 (Th-1) pattern of cytokines and natural killer (NK) cells activity may also induce abortion. Various forms of treatment like antithrombotic therapies such as aspirin and heparin, intravenous immunoglobulin (IVIg) therapy, immunotherapy with paternal lymphocytes and vitamin D3 therapy are effective mode of treatment for unexplained cause of fetal loss in women with RSA.

Pregnancy Outcome in Recurrent Aborters is Not Influenced by Chlamydia IgA and/or G

PROBLEM

It is unclear whether chlamydia infection influences the miscarriage rate and immunological factors in patients with recurrent miscarriage.

METHOD OF STUDY

Chlamydia DNA, IgA and IgG to Chlamydia trachomatis, natural killer cell activity, complement 3 (C3), C4, hemolytic complement, antinuclear antibodies, antiphospholipid antibodies, prolactin, activated partial thromboplastin time, prothrombin time and fibrinogen were examined in 504 patients with a history of two or more consecutive first-trimester miscarriages. Subsequent pregnancy outcomes were compared between cases with and without antibodies to C. trachomatis.

RESULTS

Totals of 10 of 30 and 48 of 201 patients receiving no medication miscarried subsequently with and without chlamydia infection. Chlamydia IgA and/or IgG were associated with a high level of C3 but not other immunological and coagulatory parameters.

CONCLUSION

Antibodies to C. trachomatis do not influence subsequent pregnancy outcome in patients with a history of recurrent miscarriage.

Association of anticardiolipin antibody and C677T in methylenetetrahydrofolate reductase mutation in women with recurrent spontaneous abortions: a new path to thrombophilia?

CONTEXT

Recurrent spontaneous abortion (RSA) has been associated with venous thrombosis in the mother. Acquired and inherited thrombophilia factors are possible causes.

OBJECTIVE

To evaluate the association between thrombogenic factors and recurrent spontaneous abortion.

TYPE OF STUDY

Case-control study.

SETTING

Centro de Atenção Integral à Saúde da Mulher, Universidade Estadual de Campinas.

METHODS

40 ml of blood was collected from 88 women attending an RSA clinic and 88 fertile women attending a family planning clinic, to evaluate the presence of acquired and inherited thrombophilia factors. Anticardiolipin antibodies (ACA), lupus anticoagulant and deficiencies of proteins C and S and antithrombin III were evaluated by enzyme-linked immunosorbent assay (ELISA), dilute Russell Viper Venom time (dRVVT), coagulometric and chromogenic methods. DNA was amplified by the polymerase chain reaction (PCR) to study factor V Leiden and G20210A mutations in the prothrombin gene and C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene. Data were analyzed using odds ratios and a regression model for age adjustment. Fishers exact test was used to evaluate statistical relationships between associated factors and RSA.

RESULTS

ACA was detected in 11 women with RSA and one fertile woman. Heterozygous C677T was detected in 59 women with RSA and 35 fertile women. Concomitant presence of ACA and C677T was found in eight women with RSA and no fertile women (p < 0.01).

DISCUSSION

The meaning of the association between C677T mutation in the MTHFR gene and ACA is still not clear. It is possible that an inherited factor that alone would not strongly predispose a woman to thrombosis could, when associated with an acquired factor, start the process and increase the likelihood of thrombosis expression.

CONCLUSIONS

ACA and C677T in the MTHFR gene are statistically associated with RSA. The association of these two conditions is a new finding in thrombogenic factors and RSA.

Vasoconstrictively acting AT1R A1166C and NOS3 4/5 polymorphisms in recurrent spontaneous abortions (RSA)

PROBLEM

Inadequate uteroplacental perfusion is one of the main reasons for recurrent spontaneous abortions (RSA). Coagulation, fibrinolysis, and vasoconstriction affect tissue perfusion. These systems are regulated by different gene products. Polymorphisms can modulate the expression levels of the respective genes and can thereby affect perfusion. Vasoconstriction is influenced by the expression of endothelial nitric oxide synthase (eNOS) and of the angiotensinogen II type 1 receptor (AT1R).

METHOD

The aim of our study was to investigate, whether two polymorphisms in the AT1R and NOS3 genes shown to result in maternal vasoconstriction are associated with an increased risk for RSA.

RESULTS

Our data indicate that the vasoconstrictively acting genotypes AT1R C/C and NOS3 4/4 are of similar prevalence in RSA patients and in controls.

CONCLUSION

Results do not show any influence of the polymorphisms studied on early pregnancy development. This is in concordance with the concept of an independent regulation of placental perfusion.

No Association of C677T Methylenetetrahydrofolate Reductase and an Endothelial Nitric Oxide Synthase Polymorphism with Recurrent Pregnancy Loss

PROBLEM

It is controversial whether polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and the endothelial nitric oxide synthase (eNOS) are associated with recurrent pregnancy loss.

METHOD OF STUDY

We studied the frequency of the C677T polymorphism of MTHFR and a eNOS gene polymorphism, as well as the plasma levels of homocysteine and NO, in 85 cases with a history of two or more unexplained embryonal losses, 40 patients suffering fetal loss and 76 controls.

RESULTS

The frequency of the MTHFR gene T allele, which has been reported to be associated with miscarriages, in patients suffering fetal loss was rather significantly lower than in controls whereas there was no difference in the frequency of the eNOS gene A allele. There were no differences in the plasma homocysteine levels among the three groups. However, the NO concentrations in the embryonal loss and fetal loss groups were significantly higher than that in controls.

CONCLUSION

We conclude that the NO concentration but not the polymorphism of MTHFR and eNOS gene and hyperhomocysteinemia are associated with recurrent pregnancy loss in Japanese.

Factor XII deficiency: a thrombophilic risk factor for retinal vein occlusion

PURPOSE

Factor XII deficiency is among the coagulation disorders that have been implicated in major thromboembolic events. However, little is known about an association of this coagulation disorder and retinal vessel occlusion. In the current study, we investigated the prevalence of factor XII deficiency in patients with retinal vein occlusion (RVO) with reference to age and cardiovascular risk factors.

DESIGN

Cross-sectional study.

METHODS

A cohort of 150 consecutive patients with central or branch retinal vein occlusion and 135 subjects matched for age and gender were prospectively screened for factor XII deficiency. Both cohorts were divided into two subgroups (<= 45 or >45 years), depending on the patients' age at the time of the RVO or a previous thromboembolic event.

RESULTS

Overall, factor XII deficiency was found to be present in 14 (9.3%) of 150 patients and in 1 (0.7%) of 135 controls (P =.0009). Patient age <= 45 years at the time of the RVO or a previous thromboembolic event was associated with a high prevalence of factor XII deficiency (18%). By contrast, only 5 (5%) of 100 patients >45 years (P =.016) and none of the young controls (P =.0001) tested positive for factor XII deficiency. The prevalence among patients >45 years was similar to that found in age-matched controls (2%; P =.66).

CONCLUSIONS

Our results indicate that factor XII deficiency is highly prevalent in RVO patients <= 45 years of age. By contrast, the prevalence of factor XII deficiency in RVO patients older than 45 years appears to be similar to that seen in healthy individuals.

Factor XII deficiency is strongly associated with primary recurrent abortions

OBJECTIVE

To evaluate factor XII deficiency in women with primary and secondary recurrent abortion.

DESIGN

Prospective case-control study.

SETTING

University hospital.

PATIENT(S)

Sixty-seven women with primary and 33 women with secondary recurrent abortion of unexplained nature and 49 healthy controls with no history of thrombotic disease or adverse pregnancy outcomes. MAIL OUTCOME MEASURE(S): Plasma factor XII activity, activated protein C resistance, factor V Leiden mutation analysis, protein C, protein S, antithrombin III, karyotyping, and anticardiolipin antibodies.

RESULT(S)

Ten of 67 women with primary recurrent abortion (14.9%) and 4 of 33 women (12.1%) with secondary recurrent abortion had reduced factor XII activity (<60%). These results are highly significant in the former group and showed a tendency toward significance in the latter group. All controls had normal factor XII activity.

CONCLUSION(S)

Factor XII deficiency is strongly associated with primary recurrent abortion, and women with secondary recurrent abortion show a tendency toward factor XII deficiency.

Inherited Thrombophilia: Impact on Human Reproduction

The development of thrombotic disorders is a major threat for young women during pregnancy. It is one of the main causes of pregnancy-related disorders, which may also result in harm for the conceptus. Successful pregnancies require an even balance of coagulation and fibrinolysis, in order to secure stabilization of the basal plate as well as adequate placental perfusion. Thrombophilia is a laboratory definition for pre-disposing factors of thrombosis, which can be inherited or acquired. Many individuals, who carry a thrombotic defect remain asymptomatic, at least until additional boosting factors arise. The documentation of thrombophilic causes of recurrent miscarriage or pregnancy-related disorders is important, because of availability of effective early treatment. There is a rapidly growing awareness on the relationship of genetic factors influencing hemostasis and pregnancy-related disorders. The aim of our review is to summarize this knowledge, focusing on common genetic variations.

Thromboprophylaxis improves the live birth rate in women with consecutive recurrent miscarriages and hereditary thrombophilia

The effect of thromboprophylaxis with low molecular weight heparin (LMWH), on the subsequent live birth rate, in thrombophilic women with recurrent miscarriage has not been sufficiently assessed. The present study is a cohort study undertaken to assess the effect of enoxaparin on the subsequent live birth rate in women with hereditary thrombophila. Eighty-five patients with three or more consecutive pregnancy losses and a hereditary thrombophilia subsequently conceived. Thirty-seven were treated with daily subcutaneous injections of enoxaparin 40 mg and 48 were not treated. The outcome of the subsequent pregnancy was assessed in both groups of patients in terms of live births or repeat miscarriage. Forty-seven of the 85 patients were subsequently delivered, 38 have miscarried. Twenty-six of the 37 pregnancies in treated patients (70.2%) resulted in live births, compared with 21 of 48 (43.8%) in untreated patients (P < 0.02, OR 3.03, 95% CI 1.12-8.36). The beneficial effect was seen mainly in primary aborters, i.e. women with no previous live births (P < 0.008, OR 9.75, 95% CI 1.59-52.48). This benefit was also found in patients with a poor prognosis for a live birth (five or more miscarriages), where the live birth rate was increased from 18.2% to 61.6%. However, the benefit was not statistically significant, probably due to the small number of patients. If the beneficial effects of enoxaparin are confirmed by additional studies, thromboprophylaxis can be recommended for patients with hereditary thrombophilia and recurrent pregnancy loss.

Hereditary thrombophilias are not associated with a decreased live birth rate in women with recurrent miscarriage

OBJECTIVE

To assesses the live birth rate without treatment in women with hereditary thrombophilia who have recurrent miscarriage and women without thrombophilia who have recurrent miscarriage.

DESIGN

Prospective observational study.

SETTING

Tertiary referral unit in university hospital.

PATIENT(S)

One hundred twenty women with thrombophilia and 65 women without thrombophilia.

MAIN OUTCOME MEASURE(S)

Number of live births or repeated miscarriages.

RESULTS

Of the 185 patients, 44 with thrombophilia and 26 without thrombophilia have conceived. Nineteen of the 44 pregnancies (43.2%) in thrombophilia patients have terminated in live births, compared with 8 of 26 pregnancies (30.8%) in patients without thrombophilia. This difference is not statistically significant.

CONCLUSIONS

Hereditary thrombophilia did not seem to affect the live birth rate in women with recurrent miscarriage.

Coagulation factor XII activity, but not an associated common genetic polymorphism (46C/T),is linked to recurrent miscarriage

OBJECTIVE

To investigate whether a factor XII genetic polymorphism is associated with first-trimester embryonal loss.

DESIGN

Prospective case-control study. SETTING; Nagoya City University Hospital.

PATIENT(S)

Eighty-three patients with a history of two or more unexplained first-trimester recurrent miscarriages and 67 controls with no obstetric complications or history of miscarriage.

MAIN OUTCOME MEASURE(S)

Plasma factor XII activity, a genetic polymorphism (46 C-->T) of factor XII, lupus anticoagulant, and beta(2)glycoprotein I dependent anticardiolipin antibodies.

RESULT(S)

Ten of the 83 patients and 1 of the 67 controls had decreased factor XII activity; the difference in frequency was statistically significant. Wild-type (CC), heterozygote (CT), and homozygote (TT) allele patterns were observed in 8, 36, and 39 patients, respectively, compared with 11, 20, and 36 of the patients and controls, respectively. The mean (+/- SD) corresponding factor XII activity was 154.8 +/- 44.8%, 112.7 +/- 30.2%, and 66.2 +/- 29.2% in patients and 164.6 +/- 26.7%, 114.3 +/- 28.1%, and 70.4 +/- 18.1% in controls. The two groups did not differ in the frequency of the T allele or categories of factor XII activity.

CONCLUSION(S)

Factor XII activity overall, but not the 46C/T common genetic polymorphism, is associated with recurrent miscarriage.