Lack of association between serum antibodies to Chlamydia trachomatis and a history of recurrent pregnancy loss

Australasian recurrent pregnancy loss clinical management guideline 2024, part II

Part II of the Australasian guideline for the investigation and management of recurrent pregnancy loss (RPL) provides evidence-based guidance on the management of RPL provided. The implications of inherited and acquired thrombophilia with respect to RPL and suggestions for clinical management are provided. Autoimmune factors, including human leukocyte antigen, cytokines, antinuclear antibodies and coeliac antibodies, and guidance for management are discussed. Infective, inflammatory and endometrial causes of RPL are discussed in detail. Environmental and lifestyle factors, male factor and unexplained causes are outlined. Levels of evidence and grades of consensus are provided for all evidence-based statements.

Molecular Evidence of Chlamydia trachomatis Infection and Its Relation to Miscarriage

Background

Chlamydia trachomatis (CT) infection is the most common sexually transmitted disease in the world that can persist and also ascend in the genital tract. This intracellular and silent infection is related to some adverse pregnancy outcomes, such as miscarriage. The aims of this study were to explore the best CT screening tests using blood and vaginal samples and to investigate the correlation between CT infection and the incidence of miscarriage.

Materials and Methods

This case-control study was done in October 2013 through June 2014, using purposive sampling from 157 female participants with or without a history of miscarriage. The samples were taken after each participant had signed a letter of consent and had completed a questionnaire. To achieve the objectives of this study, polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) tests were performed on vaginal swabs and blood samples, respectively.

Results

PCR results showed a significantly higher CT infection rate in the miscarriage group compared to the control group (11.3 vs. 0%, P=0.007). Anti-CT IgG and IgA antibodies were found in 4.2 and 2.1% of cases in the miscarriage group, and in 1.7 and 6.7% of cases in the control group, respectively (P>0.05). Despite lower humoral responses in this study, positive samples were detected only by one of the following techniques; PCR, ELISA IgA and ELISA IgG. It also should be noted that PCR worked best in terms of detection.

Conclusion

Based on the obtained data, there is a strong association between molecular evidence of CT infection and miscarriage. A higher rate of CT detection in molecular tests compared to serological assays suggests that PCR could be used as the first-choice assay for detection of C. trachomatis. However, the importance of serological tests in detecting potential past CT infection or upper genital infection not amenable to sampling is undeniable.

Chlamydia trachomatis and chlamydia-like bacteria: new enemies of human pregnancies

PURPOSE OF REVIEW

This review provides an update on the roles of Chlamydia trachomatis and the related Waddlia chondrophila and Parachlamydia acanthamoebae in miscarriage, stillbirths and preterm labour in humans. A broad audience, including microbiologist, infectiologists, obstetricians and gynaecologists, should be aware of the potential threat of these Chlamydiales for human reproduction.

RECENT FINDINGS

Despite increasing laboratory techniques and possibilities to perform diagnostic tests, the cause of miscarriage is only identified in 50% of the cases. Intracellular bacteria, such as C. trachomatis and Chlamydia-related bacteria, are difficult to detect in routine clinical samples and could represent possible agents of miscarriages. C. trachomatis is considered the world largest sexual transmitted bacterial agent and is associated with adverse pregnancy outcome in human. In the last decade Chlamydia-like organisms, such as W. chondrophila and P. acanthamoebae, have also been associated with adverse pregnancy outcomes in human and/or animals.

SUMMARY

We review here the current evidences for a pathogenic role in humans, the diagnostic approaches and possible treatment options of C. trachomatis, W. chondrophila and P. acanthamoebae.

Population-Based Study of Prediagnostic Antibodies to Chlamydia trachomatis in Relation to Adverse Pregnancy Outcome

BACKGROUND

Chlamydia trachomatis infection is one of the most common sexually transmitted reported bacterial infections worldwide. The well-known sequelae of chlamydial infection include pelvic inflammatory disease and tubal factor infertility, but the evidence linking C. trachomatis infection and adverse pregnancy outcome is inconsistent and has been largely based on case-control studies with limited study populations. We evaluated this link in a population-based longitudinal biobank health registry setting.

METHODS

The association between C. trachomatis major outer membrane protein (MOMP) peptide-specific IgG antibodies and ectopic pregnancy, miscarriage, and preterm delivery was examined in a prospective case-control study nested in the Finnish Maternity Cohort. Ectopic pregnancy and miscarriage cases were identified through the Hospital Discharge Register 1998-2005; cases with preterm deliveries were identified through the Finnish Medical Birth register 1988-2005. Control samples were retrieved from the Finnish Maternity Cohort serum bank. A total of 800 cases of ectopic pregnancy, 800 cases of miscarriage, and 1350 cases of preterm birth were included. Equal number of pregnant women without the outcome diagnosis served as controls. The cases and controls were matched by sampling time, at the serum sampling and postal code district.

RESULTS

Antichlamydial IgG antibodies were associated with ectopic pregnancy. Positive antibody levels were found in 21.0% of cases and 14.6% of controls (P = 0.001; odds ratio, 1.56; 95% confidence interval, 1.20-2.03). Previous exposure to C. trachomatis, as indicated by serum antibodies, doubled the risk of ectopic pregnancy within age and was highest among women 35 years or older. Antichlamydial IgG antibody rates between the cases with miscarriage (16.3% in cases vs. 16.8% in controls) or preterm delivery (18.1% vs. 18.1%) and controls did not differ.

CONCLUSIONS

Our findings confirm the association between previous exposure to C. trachomatis and ectopic pregnancy. We found no association between C. trachomatis seropositivity and miscarriage or preterm birth.

Maternal exposure to sexually transmitted infections and schizophrenia among offspring

Animal models and epidemiologic studies suggest that prenatal maternal infection, and sexually transmitted infection (STI) in particular, is associated with an increased risk of schizophrenia in the offspring. However, findings from prior research studies on common infections, including herpes simplex virus type 2 (HSV-2) and Chlamydia trachomatis (C. trachomatis) have been inconsistent. To investigate these associations, we conducted a case-control study nested in the population-based Finnish Prenatal Study of Schizophrenia. Using linked national registries, 963 cases with schizophrenia (ICD-10 F20) or schizoaffective disorder (ICD-10 F25), and 963 matched controls were identified from among all persons born between 1983 and 1998 in Finland. HSV-2 IgG antibody levels were quantified in archived maternal serum samples drawn during pregnancy. Mothers of 16.4% of cases versus 12.6% of controls were HSV-2 seropositive. Mean levels of maternal HSV-2 IgG were marginally higher among cases than controls (index values of 0.98 versus 0.86; p=0.06). The unadjusted odds ratio (OR) of maternal HSV-2 IgG seropositivity was 1.33 (95% confidence interval (CI)=1.03-1.72, p=0.03). Following adjustment for covariates, the relationship was attenuated (OR=1.22, CI=0.93-1.60; p=0.14). In an exploratory analysis of another STI, C. trachomatis antibodies were measured in a subsample of 207 case-control pairs drawn from the cohort. The proportions of subjects that were seropositive and the mean levels of C. trachomatis antibodies were similar for cases and controls. This study does not support a strong association of HSV-2 or C. trachomatis IgG antibodies in maternal serum during early to mid-gestation with the development of schizophrenia in the offspring.

Positive association of sperm dysfunction in the pathogenesis of recurrent pregnancy loss

BACKGROUND

Recurrent pregnancy loss (RPL) is one of the most frustrating and difficult areas in reproductive medicine, because the aetiology is often unknown and there are few evidence-based diagnostic and treatment strategies. RPL diagnosis is mainly focused on the female partner. The male factor contributing in evaluation of RPL has been less investigated, it is restricted to karyotype and basic semen analysis, assessment of functionality of sperm is largely ignored.

AIM AND OBJECTIVE

To investigate the role of sperm factors in RPL through regular semen analysis preceded with sperm function tests.

MATERIALS AND METHODS

We performed a case control study of 95 males whose partner has experienced two or more pregnancy loss as case and 37 volunteers who had fathered child/children without the history of RPL as control group. Basic semen analysis and sperm function test (Nuclear chromatin decondensation {NCD}, Hypo osmotic swelling {HOS} and Acrosome intactness test {AIT} was performed. The results were analysed by performing Independent-sample t-test using SPSS (version 14.0).

RESULTS

One individual had anatomical abnormality which was confirmed through trans-rectal ultrasound scanning and RPL group showed statistically significant (p<0.05) value for NCD, HOS and AIT and 36.8% of RPL individuals had reduced score for sperm count and motility. Less than 4% normal morphology was recorded in 16.8% individuals of RPL group.

CONCLUSION

Our study revealed that the positive association of sperm dysfunction in RPL cases, hence male may be considered for a routine part of the evaluation along with his partner in the near future in order to achieve desirable outcome.

Recurrent miscarriages, innate immunity, and autoimmune reaction to chlamydial 60-kDa heat shock protein--is there an association?

OBJECTIVE

To evaluate a potential association of immunity to the Chlamydia trachomatis 60kDa heat shock protein (ChlamHSP60) and recurrent miscarriages.

DESIGN

Prospective study.

SETTING

Outpatient miscarriage clinic of a university-based hospital.

PATIENT(S)

120 asymptomatic women with a history of recurrent miscarriages.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Determination of serum immunoglobulin G (IgG) antibodies (Ab) to ChlamHSP60 and human HSP60 and, in parallel, mannose-binding lectin (MBL) and the total hemolytic complement (CH50); medical history and clinical examination, including multiple relevant laboratory determinants.

RESULT(S)

ChlamHSP60 Ab were detected in 24 (20%) of 120 patients. Antibodies to human HSP60 were found in 19 (15.8%) of 120 patients, and more frequently in individuals who tested positive for ChlamHSP60. ChlamHSP60 were statistically significantly associated with antichlamydial IgG Ab. However, antibodies to ChlamHSP60 were not related to medical history, the number of abortions, or the time frame of fetal loss. ChlamHSP60 antibodies were not associated with the relevant variables of the coagulation cascade, a panel of autoimmune parameters including thyroid autoimmunity, deficiencies of the complement system (low MBL), or with antibodies to common infectious diseases. No statistically significant differences were was found when comparing the prevalence of ChlamHSP60 Ab in the study group with recurrent miscarriages and 90 controls (women attending for an annual pelvic examination).

CONCLUSION(S)

Immunity to ChlamHSP60 does not play a major role in the etiology of recurrent miscarriages.

First trimester assessment of pentraxin-3 levels in women with primary unexplained recurrent pregnancy loss

OBJECTIVE

To evaluate the potential role of measuring first-trimester maternal Pentraxin-3 levels in patients with primary unexplained recurrent pregnancy loss.

STUDY DESIGN

A case control study was conducted in Ain Shams University Maternity Hospital. Cases included 45 women with primary unexplained recurrent pregnancy loss and early pregnancy failure admitted for medical or surgical termination of pregnancy. Controls (45 women) included a matched group of apparently healthy pregnant women who had at least one previous uneventful pregnancy with no previous obstetric history of adverse pregnancy outcomes. Maternal venous blood samples were collected for assay of Pentraxin-3 using enzyme-linked immunosorbent assay. The main outcome measure was the pregnancy outcome in women with elevated Pentraxin-3 levels.

RESULTS

90 participants were statistically analyzed. In the patient group, the mean Pentraxin-3 level was 12.00 ± 4.07 ng/ml, while in the control group it was 1.69 ± 0.91 ng/ml. The difference was statistically significant (p<0.001). In the patient group, Pentraxin-3 showed a significant positive correlation with the number of previous miscarriages (p=0.038).

CONCLUSION

Abnormally elevated Pentraxin-3 levels indicate the presence of an abnormally exaggerated intrauterine inflammatory or innate immune response that may cause pregnancy failure in women with primary unexplained recurrent pregnancy loss.

Role of Chlamydia trachomatis in miscarriage

To determine the role of Chlamydia trachomatis in miscarriage, we prospectively collected serum, cervicovaginal swab specimens, and placental samples from 386 women with and without miscarriage. Prevalence of immunoglobulin G against C. trachomatis was higher in the miscarriage group than in the control group (15.2% vs. 7.3%; p = 0.018). Association between C. trachomatis-positive serologic results and miscarriage remained significant after adjustment for age, origin, education, and number of sex partners (odds ratio 2.3, 95% confidence interval 1.1-4.9). C. trachomatis DNA was more frequently amplified from products of conception or placenta from women who had a miscarriage (4%) than from controls (0.7%; p = 0.026). Immunohistochemical analysis confirmed C. trachomatis in placenta from 5 of 7 patients with positive PCR results, whereas results of immunohistochemical analysis were negative in placenta samples from all 8 negative controls tested. Associations between miscarriage and serologic/molecular evidence of C. trachomatis infection support its role in miscarriage.

Role of the infections in recurrent spontaneous abortion

Embryo-fetal infections have been reported to cause recurrent spontaneous abortions (RSAs) at a rate lower than 4%. The possible mechanisms include production of toxic metabolic byproducts, fetal or placental infection, chronic endometrial infection, and chorio-amnionitis. Viruses appear to be the most frequently involved pathogens, since some of them can produce chronic or recurrent maternal infection. In particular, cytomegalovirus during pregnancy can reach the placenta by viremia, following both primary and recurrent infection, or by ascending route from the cervix, mostly following reactivation. Another herpesvirus, herpes simplex virus type 2, less frequently type 1, causes recurrent infections of the genital tract, which can involve the feto-placental unit. Parvoviruses have also been implicated in the development of repeated fetal loss. Among bacterial infections, Chlamydia trachomatis, Ureaplasma urealyticum,and Mycoplasma hominis have been mostly associated with occurrence of RSA. An increased risk of abortion among women with bacterial vaginosis (BV) during early pregnancy was also shown, but questions arise about the role of chronic BV in its occurrence. Although a definitive relationship between recurrently active infections and RSA is still lacking, mostly due to difficulties in demonstrating the pathogenic role of each individual isolated pathogen, diagnosis and therapy of RSA-related infections should be attempted. The diagnosis of infectious agents as a possible cause of RSA might lead to a therapeutic approach with antiviral drugs and antibiotics or using immunoglobulins, which can display both anti-infective neutralizing and immunomodulating properties.

The influence of Chlamydia trachomatis infection on spontaneous abortions

PURPOSE

The aim of the study was to evaluate the frequency of Chlamydia trachomatis (C.t.) infection among women who experienced a miscarriage.

MATERIALS AND METHODS

Patients referred to the Centre for STD Research and Diagnostics in Bialystok from the Department of Perinatology and from gynaecological outpatient clinics, after spontaneous abortion were enrolled in the study. C.t. infection diagnostics were performed among 76 women with 1 miscarriage and 44 patients with > or =2 miscarriages in anamnesis. Forty-six patients in the 2nd and the 3rd trimester of normal pregnancy served as a comparative group. Endocervical swabs as well as blood serum were obtained. To detect chlamydial DNA, direct PCR method was performed (Roche, Molecular Systems, N.J., USA). To detect IgA and IgG specific anti-chlamydial antibodies we used immunoenzymatic assay (medac, Hamburg, Germany).

RESULTS

In patients with 1 miscarriage (gr.1), C.t. infection by means of PCR was detected in 11.8% of women (p=0.029), in patients with > or =2 miscarriages (gr.2) in 9.1% (p=0.198) and in the comparative group (gr.0) in 2.2%. Specific anti-chlamydial antibodies IgA class were detected in: 7.9 (p=0.082) in group 1, 4.5% (p=0.236) in group 2 and in 0% in group 0, and IgG class in 21.1% (p=0.024), 36.4% (p=0.000) and in 4.4%, respectively.

CONCLUSIONS

1. C.t. infection is an important causative agent of miscarriages in women. 2. C.t. infection diagnostic procedures should be considered in screening tests during pregnancy.

Associations between tumor necrosis factor-alpha and lymphotoxin-alpha polymorphisms and idiopathic recurrent miscarriage

Heightened expression of tumor necrosis factor (TNF)-alpha and lymphotoxin-alpha (LT-alpha) was associated with pregnancy complications, including idiopathic recurrent miscarriage (RM). Whereas TNF-alpha and LT-alpha gene polymorphisms affect serum cytokine concentrations, their contribution to RM is controversial. The single nucleotide polymorphisms (SNPs) TNF-alpha (-238G/A, -308G/A) and LT-alpha (+252A/G) were investigated in 350 RM women and 200 control women. Higher frequency of the TNF-alpha -238A, but not the TNF-alpha -308A or the LT-alpha+252G, allele was seen in patients, with comparable frequencies of TNF-alpha -238G/A, TNF-alpha -308G/A, and LT-alpha+252A/G genotypes seen between both groups, except for TNF-alpha -238G/G, which was lower in patients. Regression analysis confirmed the association of the TNF-alpha -238G/A SNP with idiopathic RM, and both TNF-alpha -308A/TNF -238G/LT-alpha+252G and TNF-alpha -308G/TNF-alpha -238A/LT-alpha+252G haplotypes played a susceptible role in idiopathic RM. TNF-alpha -238G/A and -238A/A, and LT-alpha+252G/G genotypes were positively associated only with exclusively early RM. This supports the concept of the association of TNF-alpha (-238G/A) and LT-alpha (+252A/G) polymorphic variants in idiopathic RM.

Emerging role of Chlamydia and Chlamydia-like organisms in adverse pregnancy outcomes

PURPOSE OF THE REVIEW

This review considers the roles of Chlamydia spp. and newly identified Chlamydia-like organisms in miscarriage, stillbirths and preterm labour in both animals and humans.

RECENT FINDINGS

The cause of miscarriage, stillbirth and preterm labour often remains unexplained. Intracellular bacteria that grow either poorly or not at all on media used routinely to detect human pathogens could be the aetiological agents of these obstetrical conditions. There is growing evidence that Chlamydia trachomatis, Chlamydophila abortus, Chlamydophila psittaci and Chlamydophila pneumoniae infections may result in adverse pregnancy outcomes in humans and/or animals. Waddlia, a Chlamydia-like organism first isolated from an aborted bovine, has emerged as an agent of abortion in cattle. Recently, Waddlia was also implicated in human foetal death. Moreover, Parachlamydia acanthamoebae is also abortigenic in ruminants. Whether additional novel Chlamydia-like organisms, such as Protochlamydia amoebophila, Neochlamydia hartmanellae, Criblamydia sequanensis, Rhabdochlamydia crassificans and Simkania negevensis, are involved in foetal loss or premature delivery remains to be determined.

SUMMARY

This review provides an update on the consequences of chlamydial infection during pregnancy and summarizes current evidence suggesting that some Chlamydia-related organisms are probably emerging obstetrical pathogens.

Causes of Fetal Wastage

Fetal wastage has many causes, but genetic factors are by far the most common. The earlier the pregnancy loss occurs, the greater the likelihood of genetic causation. Among first trimester abortions, 50% to 80% show chromosomal abnormalities, usually aneuploidy. This is greater than all other causes combined. Chromosomal numerical abnormalities can be recurrent and sporadic; failure to take this into account is a major pitfall in many reports addressing causation. Moreover, many causes of fetal wastage that are traditionally considered to be "nongenetic" are actually the result of perturbations of gene products-proteins. Among nongenetic causes of first trimester fetal wastage, the best established are thyroid abnormities; antifetal antibodies; and the inherited and acquired thrombophilias. The latter are more established in the second trimester. Uterine anomalies can lead to second trimester losses. Infections seem uncommon, and alloimmune causes are not validated.

Genetic Evaluation and Counseling of Couples with Recurrent Miscarriage: Recommendations of the National Society of Genetic Counselors

The objective of this document is to provide recommendations for genetic evaluation and counseling of couples with recurrent miscarriage (RM). The recommendations are the opinions of the multidisciplinary Inherited Pregnancy Loss Working Group (IPLWG), with expertise in genetic counseling, medical genetics, maternal fetal medicine, internal medicine, infectious disease, cytogenetics, and coagulation disorders. The IPLWG defines RM as three or more clinically recognized consecutive or non-consecutive pregnancy losses occurring prior to fetal viability (<24 weeks gestation). These recommendations are provided to assist genetic counselors and other health care providers in clinical decision-making, as well as to promote consistency of patient care, guide the allocation of medical resources, and increase awareness of the psychosocial and cultural issues experienced by couples with RM. The IPLWG was convened with support from the March of Dimes Western Washington State Chapter and the University of Washington Division of Medical Genetics. The recommendations are U.S. Preventive Task Force Class III, and are based on clinical experiences, review of pertinent English-language published articles, and reports of expert committees. This document reviews the suspected causes of RM, provides indications for genetic evaluation and testing, addresses psychosocial and cultural considerations, and provides professional and patient resources. These recommendations should not be construed as dictating an exclusive course of medical management, nor does the use of such recommendations guarantee a particular outcome. The professional judgment of a health care provider, familiar with the circumstances of a specific case, should always supersede these recommendations.

Evidence-based care of recurrent miscarriage

Between 0.5 and 1.0% of couples experience recurrent pregnancy loss (RPL), which is defined as three or more consecutive miscarriages. Losses are classified as pre-embryonic (<5 weeks), embryonic (5-10 weeks) or fetal (>10 weeks). Genetic abnormalities are responsible for RPL in 2-4% of these couples. Inadequate progesterone production has been proposed a cause of RPL and progesterone is given to prevent miscarriage, despite a lack of supportive evidence. The factor V Leiden and prothrombin G20210A mutations are common inherited thrombophilias also associated with RPL. Antenatal thromboprophylaxis is sometimes recommended although no data exist regarding efficacy. Antiphospholipid syndrome is known to cause RPL and antenatal thromboprophylaxis reduces the risk of miscarriage. Uterine abnormalities might also result in RPL. About 50% of cases of RPL have no identifiable cause. Alloimmune incompatibility has been proposed as a cause for RPL in these women. The concept of alloimmune-related RPL has not been scientifically validated.

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.

First-trimester pregnancy loss and active Chlamydia trachomatis infection: correlation and ultrastructural evidence

The incidence of Chlamydia trachomatis (Ct) infection and the possible correlation between couples presenting with first-trimester spontaneous abortions and active Ct infection was assessed. Additionally, the ability of Ct to infect zona-free hamster oocytes was explored by incubating the oocytes with spermatozoa from infected patients. A total of 961 women and 750 men consulting our reproductive medicine centre were screened for Ct using direct immunofluorescence. The general incidence of Ct infection was 9.4% in females (90 of 961) and 13.9% in males (104 of 750). In women with spontaneous abortions the incidence of Ct was 21.0% (14 of 66) compared with 8.9% (23 of 59) for women without spontaneous abortions and term pregnancies (chi-square, P < 0.05). When both partners of the couples were considered (one or both partners infected), the incidence rose to 68.8% (22 of 32) (chi-square, P < 0.001). In vitro studies using electron microscopy demonstrated the presence of Ct on the surface of and inside the oocyte. These results indicate a correlation between an active Ct infection and spontaneous abortion. Electron microscopy studies suggested the possibility of direct oocyte infection by Ct. Two models are proposed for the pathogenesis of Ct-related early abortions: (i) direct zygote infection, and (ii) immune response to heat shock proteins expressed by the zygote and triggered by previous Ct infections.