ANXA5 and VEGFA Gene Variants in Women with Early Pregnancy Losses from North Macedonia

Early pregnancy loss (EPL) is the most common pregnancy complication, found in approximately 15% of all clinically recognized pregnancy complications. Up to date, various maternal as well as fetal factors are reported as a cause of EPLs. However, in approximately 50% of EPL cases, the exact cause is not clearly identified and these cases are referred as idiopathic. The aim of our study was to examine the association of four distinct variants in the ANXA5 gene and two variants within the VEGFA gene in a cohort of women with EPLs from North Macedonia. This group was compared to a control group of women matched by ethnic background without pregnancy loss and at least one live birth. We also aimed to establish an effective and cost-efficient method for their detection based on multiplex single-base extension. Among 190 women experiencing EPLs, and 190 samples from women without a history of pregnancy loss (control group), our results demonstrated a statistically significant prevalence of heterozygotes for the M2/ANXA5 haplotype in women with EPLs, compared to the control group (p=0.0006). In the analyses comparing genotypic frequencies for the variants in the VEGFA gene, higher frequencies were generally observed among women experiencing EPLs, however without statistical significance. Our study aligns with multiple studies showing that M2 and M1 ANXA5 haplotypes are more prevalent in patients with pregnancy loss and presents an affordable genotyping technique for the specific ANXA5 and VEGFA variants.

Use of anticoagulants to improve pregnancy outcomes in couples positive for M2 haplotype: A systematic review

BACKGROUND

Placental mediated pregnancy complications (PMPC) are common, often recurring, and pose a significant health risk to mother and fetus. Evidence suggests that the hypercoagulable state associated with many PMPC, could reflect reduced expression of Annexin 5 (ANXA5), a naturally occurring anticoagulant protein in placental tissue. The ANXA5 M2 haplotype is a genetic variant, which results in reduced expression of ANXA5 protein. M2 haplotype carrier couples may therefore be at increased risk of PMPC. Evidence regarding the effectiveness of anticoagulation to prevent PMPC is inconsistent. Furthermore, studies have not selected or stratified for M2 haplotype carriers, in whom there is a predisposition to hypercoagulability, to assess the effectiveness of anticoagulation, which may vary from those without the M2 haplotype.

OBJECTIVES AND RATIONALE

The aim of this study was to systematically review the current evidence to assess whether anticoagulant treatment improves pregnancy outcomes in couples positive for M2 haplotype.

SEARCH METHODS

The review was registered on PROSPERO (CRD42022343943). A comprehensive literature search was performed using MEDLINE, Embase and Cochrane collaboration databases from inception to January 2023. Two reviewers assessed the articles for eligibility and extracted the data simultaneously. Primary outcome was successful pregnancy and live birth. Secondary outcomes included PMPC (implantation failure, miscarriage, pre-eclampsia, preterm birth and fetal growth restriction).

OUTCOMES

From a pool of 410 references, 10 were selected for full text review, of which three studies (a post hoc analysis of a randomised controlled trial, cohort study and a case report) were included in this review. Included studies comprised of 223 individuals, 129 of whom who received anticoagulation treatment after testing positive for M2 haplotype. The studies collectively showed an improvement in pregnancy outcomes in M2 haplotype positive individuals however, given the heterogeneity of studies, it was not possible to conduct a meta-analysis and draw firm conclusions.

WIDER IMPLICATIONS

Current evidence is limited, such that the value of screening couples for the M2 haplotype to select or stratify for treatment with prophylactic anticoagulation remains unknown. Thus, further studies including well designed, large, multi-centre randomised controlled trials are required to assess whether anticoagulation treatment will be effective in improving pregnancy outcomes in M2 haplotype couples.

Research progress on ANXA5 in recurrent pregnancy loss

The incidence of recurrent pregnancy loss (RPL) in fertile women ranges from 1% to 5%, of which about 50% of them are due to unknown causes. The possible pathogenesis of RPL is an urgent problem to be solved in the clinical. Mutations or polymorphisms of certain genes in the coagulation mechanism are associated with susceptibility to thrombotic diseases and are one of the main reasons for the occurrence of RPL. Among them, the ANXA5 gene was newly studied and some single nucleotide polymorphisms (SNPs) in the promoter region of ANXA5 have been reported to be associated with RPL in multiple races. In this review, we summarized the research progress on the correlation between the SNPs in ANXA5 and RPL, hoping to provide some valuable guidance for the future studies.

Venous thromboembolism prophylaxis for women at risk during pregnancy and the early postnatal period

BACKGROUND

Venous thromboembolism (VTE), although rare, is a major cause of maternal mortality and morbidity. Some women are at increased risk of VTE during pregnancy and the early postnatal period (e.g. caesarean section, family history of VTE, or thrombophilia), and so prophylaxis may be considered. As some methods of prophylaxis carry risks of adverse effects, and risk of VTE is often low, benefits of thromboprophylaxis may be outweighed by harms.

OBJECTIVES

To assess the effects of thromboprophylaxis during pregnancy and the early postnatal period on the risk of venous thromboembolic disease and adverse effects in women at increased risk of VTE.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (18 October 2019). In addition, we searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) for unpublished, planned and ongoing trial reports (18 October 2019).

SELECTION CRITERIA

Randomised trials comparing one method of thromboprophylaxis with placebo or no treatment, or two (or more) methods of thromboprophylaxis.

DATA COLLECTION AND ANALYSIS

At least two review authors assessed trial eligibility, extracted data, assessed risk of bias, and judged certainty of evidence for selected critical outcomes (using GRADE). We conducted fixed-effect meta-analysis and reported data (all dichotomous) as summary risk ratios (RRs) with 95% confidence intervals (CIs).

MAIN RESULTS

Twenty-nine trials (involving 3839 women), overall at moderate to high risk of bias were included. Trials were conducted across the antenatal, peripartum and postnatal periods, with most in high-income countries. Interventions included types and regimens of heparin (low molecular weight heparin (LMWH) and unfractionated heparin (UFH)), hydroxyethyl starch (HES), and compression stockings or devices. Data were limited due to a small number of trials in comparisons and/or few or no events reported. All critical outcomes (assessed for comparisons of heparin versus no treatment/placebo, and LMWH versus UFH) were considered to have very low-certainty evidence, downgraded mainly for study limitations and imprecise effect estimates.  Maternal death was not reported in most studies. Antenatal (± postnatal) prophylaxis For the primary outcomes symptomatic thromboembolic events pulmonary embolism (PE) and/or deep vein thrombosis (DVT), and the critical outcome of adverse effects sufficient to stop treatment, the evidence was very uncertain.  Symptomatic thromboembolic events: - heparin versus no treatment/placebo (RR 0.39; 95% CI 0.08 to 1.98; 4 trials, 476 women; very low-certainty evidence); - LMWH versus UFH (RR 0.47; 95% CI 0.09 to 2.49; 4 trials, 404 women; very low-certainty evidence); Symptomatic PE: - heparin versus no treatment/placebo (RR 0.33; 95% CI 0.02 to 7.14; 3 trials, 187 women; very low-certainty evidence); - LMWH versus UFH (no events; 3 trials, 287 women); Symptomatic DVT: - heparin versus no treatment/placebo (RR 0.33; 95% CI 0.04 to 3.10; 4 trials, 227 women; very low-certainty evidence); - LMWH versus UFH (no events; 3 trials, 287 women); Adverse effects sufficient to stop treatment: - heparin versus no treatment/placebo (RR 0.49; 95% CI 0.05 to 5.31; 1 trial, 139 women; very low-certainty evidence); - LMWH versus UFH (RR 0.07; 95% CI 0.01 to 0.54; 2 trials, 226 women; very low-certainty evidence). Peripartum/postnatal prophylaxis Vaginal or caesarean birth When UFH and no treatment were compared, the effects on symptomatic thromboembolic events (RR 0.16; 95% CI 0.02 to 1.36; 1 trial, 210 women; very low-certainty evidence), symptomatic PE (RR 0.16; 95% CI 0.01 to 3.34; 1 trial, 210 women; very low-certainty evidence), and symptomatic DVT  (RR 0.27; 95% CI 0.03 to 2.55; 1 trial, 210 women; very low-certainty evidence) were very uncertain.  Maternal death and adverse effects sufficient to stop treatment were not reported. Caesarean birth Symptomatic thromboembolic events: - heparin versus no treatment/placebo (RR 1.30; 95% CI 0.39 to 4.27; 4 trials, 840 women; very low-certainty evidence); - LMWH versus UFH (RR 0.33; 95% CI 0.01 to 7.99; 3 trials, 217 women; very low-certainty evidence); Symptomatic PE: - heparin versus no treatment/placebo (RR 1.10; 95% CI 0.25 to 4.87; 4 trials, 840 women; very low-certainty evidence); - LMWH versus UFH (no events; 3 trials, 217 women);  Symptomatic DVT: - heparin versus no treatment/placebo (RR 1.30; 95% CI 0.24 to 6.94; 5 trials, 1140 women; very low-certainty evidence); LMWH versus UFH (RR 0.33; 95% CI 0.01 to 7.99; 3 trials, 217 women; very low-certainty evidence); Maternal death: - heparin versus placebo (no events, 1 trial, 300 women); Adverse effects sufficient to stop treatment: - heparin versus placebo (no events;  1 trial, 140 women). Postnatal prophylaxis No events were reported for LMWH versus no treatment/placebo for: symptomatic thromboembolic events, symptomatic PE and symptomatic DVT (all 2 trials, 58 women), or maternal death (1 trial, 24 women). Adverse effects sufficient to stop treatment were not reported. We were unable to conduct subgroup analyses due to lack of data. Sensitivity analysis including the nine studies at low risk of bias did not impact overall findings.

AUTHORS' CONCLUSIONS

The evidence is very uncertain about benefits and harms of VTE thromboprophylaxis in women during pregnancy and the early postnatal period at increased risk of VTE. Further high-quality very large-scale randomised trials are needed to determine effects of currently used treatments in women with different VTE risk factors. As sufficiently large definitive trials are unlikely to be funded, secondary data analyses based on high-quality registry data are important.

Hold your needles in women with recurrent pregnancy losses with or without hereditary thrombophilia: Meta-analysis and review of the literature

OBJECTIVES

The use of antithrombotic prophylaxis in women with recurrent pregnancy losses (RPL) remains controversial.

METHODS

We performed meta-analysis of randomized controlled trials (RCTs) comparing low molecular weight heparin (LMWH) versus No LMWH in women with or without hereditary thrombophilia and RPL. Twelve RCTs met our inclusion criteria and 2298 women were included in this meta-analysis. Our primary end point was live birth and odds ratio (OR) for live birth are reported.

RESULTS

In women with thrombophilia the benefit of LMWH on live birth is not significant but heterogeneity of the studies is significant (OR, 2.09; 95 % CI, 0.58-7.57; p = 0.26; I² = 86 %, p = 0.0001). Considering women without thrombophilia there is no benefit of LMWH in OR of live birth and data from studies have low heterogeneity (OR, 1.25; 95 % CI, 0.88-1.78; p = 0 0.21; I² = 44 %, p = 0.07).

CONCLUSIONS

Hold your needles in women with RPL. Probably in some hereditary thrombophilic defects LMWH has a positive effect on OR for live birth.

The relevance of ANXA5 genetic variants on male fertility

PURPOSE

To investigate the effect of the anticoagulation factor annexin A5 on male fertility and to provide perspective on the influence of members of the coagulation cascade on fertility.

METHODS

Patients with normozoospermia and with unexplained severe oligozoospermia were retrospectively selected and their genomic DNA sequenced for the promoter region of ANXA5. The genotypes proportions and the odds ratio for carriership of the haplotype M2 were compared between the groups and population control. The clinical data used were gathered from parameters determined during routine clinical assessment and were compared between carriers and non-carriers within the patient groups.

RESULTS

The carrier rates for the haplotype M2/ANXA5 were of 25.73%, 20.81%, and 15.3% in the severe oligozoospermic, the normozoospermic, and the general population control groups, respectively. The OR between patients groups was of 1.31 (95% CI 0.88 to 1.96 p = 0.176). Oligozoospermic and normozoospermic patients compared with the control group had an OR of 1.9 (95% CI 1.33 to 2.73 p < 0.001) and 1.45 (95% CI 0.99 to 2.10 p = 0.054) respectively. The clinical parameters that differed between the carriers and non-carriers of the haplotype M2/ANXA5 were prolactin, α-glucosidase, and fructose. The differences were only statistically significant in the normozoospermic group.

CONCLUSIONS

Athough the infertile patient groups had a higher prevalence of promoter variants, we could not demonstrate any biologically relevant effect of lower levels of annexin A5 on most male fertility parameters. A deficiency in an anticoagulation factor does not seem to impact male fertility.

Association between M2/ANXA5 haplotype and repeated pregnancy loss: a meta-analysis

OBJECTIVE

To ascertain the magnitude and precision of the association between M2/ANXA5 haplotype and repeated pregnancy loss (RPL).

DESIGN

Meta-analysis of odds ratios.

SETTING

Not applicable.

PATIENT(S)

Subjects were women with RPL and their partners.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

The association between M2/ANXA5 haplotype and RPL was evaluated in a meta-analysis of odds ratios. We further scrutinized this association according to [1] the sequence of miscarriages, [2] the number of consecutive losses, [3] the extent of excluding other pathologies of RPL, and [4] the timing of fetal loss.

RESULT(S)

Fourteen individual studies (n = 4,664 subjects) were included in this meta-analysis. The results show that women with the M2/ANXA5 haplotype have 1.54 times (95% confidence interval, 1.08-2.20) the odds of having associated RPL compared with women with the normal haplotype, regardless of consecutive or nonconsecutive pregnancy losses. Acknowledging the clinical heterogeneity among the studies, this significant association comes with a caveat that the lower bound of the confidence interval is close to unity. In couple populations (n = 2,449), M2/ANXA5 haplotype subjects have an odds ratio of 1.48 (95% confidence interval, 1.14-1.91) of experiencing RPL, which suggests contributions from paternal M2/ANXA5 carriers in RPL.

CONCLUSION(S)

This meta-analysis ascertains that women with the M2/ANXA5 haplotype have a higher risk of experiencing RPL, especially consecutive early idiopathic RPL. Male partners with the M2/ANXA5 haplotype partly contribute to this risk. Hence, screening for the M2/ANXA5 haplotype as a panel of laboratory investigations for RPL is recommended.

Micromolar Zinc in Annexin A5 Anticoagulation as a Potential Remedy for RPRGL3-Associated Recurrent Pregnancy Loss

Deficient expression of the placental anticoagulant annexin A5 (ANXA5) has been associated with thrombophilia-related pregnancy complications and ultimately with recurrent pregnancy loss (RPL). Carrier status of M2/ANXA5 ( RPRGL3), common ANXA5 promoter variant, has been identified as genetic cause of reduced ANXA5 levels and proposed as biomarker for successful anticoagulant treatment of RPL women. A murine model of AnxA5 loss of function displayed characteristic placental pathology and fetal loss that was alleviated through anticoagulant intervention. This study identified an alternative means of supplementing anticoagulation, through elevated ANXA5 expression. Physiological micromolar Zn²⁺ stimulated ANXA5 transcription, raising ANXA5 protein expression and surface abundance on BeWo and human umbilical vein endothelial cells (HUVEC), thus resulting in prolonged coagulation times. Zn²-fed AnxA5 functionally deficient pregnant mice showed a trend to increase litter size when primiparous that grew comparable to wild-type progeny in subsequent pregnancies. Elevated AnxA5 signal upon Zn²⁺ treatment was confirmed in murine placentae. Micromolar Zn²⁺ stimulated ANXA5 expression in cell culture directly and alleviated RPL in AnxA5 genetically deficient mice, without notable toxicity effects.

Outcomes of threatened abortions after anticoagulation treatment to prevent recurrent pregnancy loss

We aimed to determine the outcome of threatened abortion in women treated with low-molecular weight heparin (LMWH) for recurrent pregnancy loss (RPL). Data of women with RPL who experienced threatened abortion while taking LMWH between 2007 and 2016 were retrospectively reviewed. All patients received the LMWH, enoxaparin (40 mg). Thrombophilia was present in 38 (33.3%) women, including 11 (9.6%) with antiphospholipid syndrome (APLS). The overall live birth rate was 58.8% (67/114). Live birth rates were 87.2% (41/47 patients) and 38.8% (26/67 patients) among those who discontinued versus those who continued LMWH treatment, respectively (P < 0.0001). Among APLS patients, live births resulted in eight of the nine women who continued LMWH. In multivariate analysis, discontinuation of LMWH was the only significant predictor of live birth outcome (P < 0.0001). Thrombophilia, presence of subchorionic haematoma, and severity of bleeding were not found to be associated with live birth outcomes. For women with threatened abortions, continuation of LMWH indicated to prevent RPL was negatively associated with live birth rates. Therefore, we support its discontinuation in this setting. Among women with APLS, LMWH continuation resulted in a relatively high live birth rate; we advocate against its withdrawal in this subset of patients.

LMWH in IVF - Biomarkers and benefits

There is biological plausibility that coagulation activation underlies a proportion of in vitro fertilisation IVF failures and recurrent early clinical pregnancy loss (RPL). However, low-molecular-weight heparin (LMWH) use, based upon previous clinical outcome alone, is not effective in preventing RPL. RPL is heterogeneous in mechanism. Identifying those with an underlying thrombotic mechanism would allow stratification for LMWH treatment. Annexin A5 is an anticoagulant protein expressed on the trophoblast surface. The annexin A5 M2 haplotype (ANXA5 M2) is associated with several placenta mediated pregnancy complications (PMPC) and poor IVF outcome. It is transmitted equally by males and females. A pragmatic observational study of IVF couples screened for M2 carriage and treated with LMWH achieved a 37.9% live birth rate, similar to an unscreened and untreated group with fewer adverse risk factors for conception and a better prognosis from assisted conception. This suggests that LMWH may counteract the adverse effects of M2 carriage. Using this biomarker to stratify IVF and PMPC patients for LMWH treatment merits further evaluation.

Genetic analysis of the M2/ANXA5 haplotype as recurrent pregnancy loss predisposition in the Malay population

PURPOSE

The aim of this study was to evaluate a new predisposition factor, M2/ANXA5 (RPRGL3), in recurrent pregnancy loss (RPL) patients of Malay origin, since it was previously known that the prevalence of this condition is relatively high among the Malay population of Malaysia, where conventional hereditary thrombophilia factors have been generally ruled out.

METHODS

A total of 232 women who had experienced ≥2 unexplained RPL and 141 available male partners were recruited, with 360 healthy Malay and 166 parous female controls. Prevalence of M2 carriage and RPL odds ratios were calculated in (a) control and patient groups; (b) clinically defined subgroups in categories of pregnancy loss, primary, secondary, and tertiary; and (c) timing of pregnancy loss in early, ≤15th gestation week and "late" fetal losses, and >15th gestation week subgroups.

RESULTS

Both male and female subjects had similar M2/ANXA5 allele frequencies. The carrier rate of M2/ANXA5 for the general Malay population was 42.2 and 34.9% for parous controls. These carrier rates compared to Malay RPL subjects (52% M2 carriers) resulted in elevated odds ratios (95% confidence interval) of 1.53 (1.1 to 2.1) and 1.97 (1.3 to 3.1) accordingly for early fetal losses. Moreover, exceeding copy numbers of M2/ANXA5 alleles seemed to afflict a greater chance of RPL in couples, especially when both partners were M2 carriers.

CONCLUSION

This study confirmed the proposed role of M2/ANXA5 as embryonic, genetically associated thrombophilia predisposition factor for early RPL among ethnic Malay of Malaysia.