Prevalence of Thyroid Autoimmunity in Women with Recurrent Pregnancy Loss

Exploring Potential Biomarkers in Recurrent Pregnancy Loss: A Literature Review of Omics Studies to Molecular Mechanisms

Recurrent pregnancy loss (RPL) is characterized by the occurrence of three or more consecutive spontaneous pregnancy losses before 20-24 weeks of gestation. Despite significant progress in the investigation of the biological pathways associated with unexplained RPL, the precise molecular mechanisms remain elusive. Recent advances in multi-omics approaches have identified numerous biomarkers that offer potential avenues for understanding the underlying complexities of RPL. The aim of this comprehensive literature review was to investigate the functional roles of these candidate markers and explore the possible key mechanisms that may contribute to RPL. We also aimed to elucidate the functional networks predicted by omics analyses, which hold promise for providing invaluable insights into novel diagnostic and therapeutic strategies for women experiencing RPL. Furthermore, this review expands on clinical implications and possible applications, highlighting those currently moving towards clinical use and ongoing studies developing in this direction.

Investigating the complications of frequent pregnancy loss in patients referred to obstetrics and gynecology clinics at King Khalid University Hospital

Background

Recurrent pregnancy loss (RPL) is a common problem affecting many women. This study aimed to investigate the baseline characteristics of 400 women with RPL and to examine any differences in baseline characteristics of the recruited women with RPL throughout the years.

Methods

This study used retrospective data, which included the records of patients with RPL who visited King Khalid University Hospital's obstetric clinic between 2019 and 2022. The records of 400 patients who met the inclusion criteria were reviewed and analyzed.

Results

The mean age of enrolled women was 36.5 ± 5.4 years, and the mean RPL was 3.8 ± 2.5. The study also revealed that there were significant statistical differences in obesity and vitamin D deficiency among women with RPL based on year (P = 0.013 and P = 0.036, respectively), whereas no significant statistical differences were found between women with RPL in terms of age, parity, diabetes, hypothyroidism, hyperprolactinemia, antiphospholipid antibodies (APLs), uterine malformation, or consanguinity.

Conclusion

Advanced maternal age, number of previous miscarriages, parity, diabetes, hypothyroidism, APLs, uterine malformations, first-degree consanguinity, and vitamin D deficiency were found to be significant risk factors associated with RPL among women in Saudi Arabia.

Autoimmune Condition Diagnosis Following Recurrent Pregnancy Loss

PROBLEM

Research has suggested a link between recurrent pregnancy loss (RPL) and cell-mediated immunity dysregulation. We aimed to determine if a history of RPL is associated with diagnosis of a cell-mediated autoimmune condition (AIC).

METHOD OF STUDY

A retrospective cohort study was conducted using the TriNetX research network. The RPL group had ≥3 spontaneous or missed abortions. Controls had at least one pregnancy but no diagnosis of RPL. Propensity score matching was used for age, race, and ethnicity. Z-test and relative risk analysis investigated the relationship between RPL and subsequent AIC diagnoses.

RESULTS

One hundred twenty-eight thousand three hundred seventy-six patients were included in each cohort. RPL was associated with an increased risk for an AIC composite (RR 1.60, 95% CI [1.51, 1.69]), Crohn's disease, Graves' disease, Hashimoto's thyroiditis, multiple sclerosis, rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus, and ulcerative colitis, but not psoriatic arthritis.

CONCLUSIONS

Using a large research database of patients with RPL, we were able to demonstrate that an antecedent diagnosis of RPL is associated with increased risk of subsequent diagnosis of an AIC, often between 1 and 10 years after RPL.

Microbiota and Recurrent Pregnancy Loss (RPL); More than a Simple Connection

Recurrent Pregnancy Loss (RPL) affects 1-2% of women, and its triggering factors are unclear. Several studies have shown that the vaginal, endometrial, and gut microbiota may play a role in RPL. A decrease in the quantity of Lactobacillus crispatus in local microbiota has been associated with an increase in local (vaginal and endometrial) inflammatory response and immune cell activation that leads to pregnancy loss. The inflammatory response may be triggered by gram-negative bacteria, lipopolysaccharides (LPS), viral infections, mycosis, or atypia (tumor growth). Bacterial structures and metabolites produced by microbiota could be involved in immune cell modulation and may be responsible for immune cell activation and molecular mimicry. Gut microbiota metabolic products may increase the amount of circulating pro-inflammatory lymphocytes, which, in turn, will migrate into vaginal or endometrial tissues. Local pro-inflammatory Th1 and Th17 subpopulations and a decrease in local Treg and tolerogenic NK cells are accountable for the increase in pregnancy loss. Local microbiota may modulate the local inflammatory response, increasing pregnancy success. Analyzing local and gut microbiota may be necessary to characterize some RPL patients. Although oral supplementation of probiotics has not been shown to modify vaginal or endometrial microbiota, the metabolites produced by it may benefit patients. Lactobacillus crispatus transplantation into the vagina may enhance the required immune tolerogenic response to achieve a normal pregnancy. The effect of hormone stimulation and progesterone to maintain early pregnancy on microbiota has not been adequately studied, and more research is needed in this area. Well-designed clinical trials are required to ascertain the benefit of microbiota modulation in RPL.

Influence of thyroid autoimmunity at various clinical stages of hypothyroidism on the risk of miscarriage before 20 weeks of gestation

PURPOSE

We aimed to clarify the influence of thyroid autoantibodies at various clinical stages of hypothyroidism on the risk of pregnancy loss before 20 weeks of gestation.

METHODS

We enrolled 230 pregnant women with a history of recurrent miscarriage. Detailed clinical history, physical examination, and laboratory testing of thyroid function, antithyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG) were applied among all participants.

RESULTS

Coexisting overt hypothyroidism and positive thyroid autoantibodies quadrupled the risk of miscarriage in women before 20 weeks of gestation (OR 4.04, 95% CI = 2.08-7.96, P < 0.001). Women with subclinical hypothyroidism (OR 1.44, 95% CI = 0.81-2.57, P = 0.132,) or who were euthyroid (OR 1.53, 95% CI = 0.86-2.73, P = 0.094) showed a non-significant risk of miscarriage even with positive thyroid autoantibodies. Thyroid-stimulating hormone (TSH) was positively correlated with the number of miscarriages rather than anti-TPO (P < 0.001 and 0.209, respectively).

CONCLUSION

Coexistence of overt hypothyroidism and thyroid autoimmunity was the only significant driver of pregnancy loss before 20 weeks of gestation.

The natural cycle protocol of endometrial preparation for frozen embryo transfer decreases the miscarriage rate in women with recurrent pregnancy loss

OBJECTIVE

To investigate whether different endometrial preparation methods lead to different results.

DESIGN

Retrospective cohort study.

PATIENTS

Women with recurrent pregnancy loss undergoing frozen embryo transfer (FET).

INTERVENTIONS

Natural cycle (NC) protocol (n = 111) with no drug or human chorionic gonadotropin (HCG) used for endometrial preparation, vs. the hormone replacement therapy (HRT) protocol (n = 797) with estrogen or gonadotropin releasing hormone agonist (GnRH-a) plus estrogen used for endometrial preparation.

MAIN OUTCOME MEASURES

Miscarriage rate and live birth rate (LBR).

RESULTS

Compared to women in the HRT protocol, women undergoing NCs had fewer previous FET cycles, lower antral follicle counts (AFCs), fewer oocytes retrieved and a thicker endometrium on the day of progesterone administration. Women in the HRT group had a higher miscarriage rate (29.4% vs. 17.2%) and a lower LBR (37% vs. 46.9%) than the rates of women in the NC group. Univariate analysis showed that female age also had a negative association with the miscarriage rate. Logistic regression indicated that endometrial preparation using the NC protocol was linked to a decreased likelihood of miscarriage.

CONCLUSIONS

The NC protocol decreased the miscarriage rate and increased the LBR for patients with recurrent pregnancy loss compared with the HRT protocol.

Before Is Better: Innovative Multidisciplinary Preconception Care in Different Clinical Contexts

CONTEXT

Implementation of pre-conception care units is still very limited in Italy. Nowadays, the population's awareness of the reproductive risks that can be reduced or prevented is very low. Purpose and main findings: We presented a new personalized multidisciplinary model of preconception care aimed at identifying and possibly reducing adverse reproductive events. We analyzed three cohorts of population: couples from the general population, infertile or subfertile couples, and couples with a previous history of adverse reproductive events. The proposal involves a deep investigation regarding family history, the personal histories of both partners, and reproductive history.

PRINCIPAL CONCLUSIONS

Preconception care is still neglected in Italy and under-evaluated by clinicians involved in natural or in vitro reproduction. Adequate preconception counseling will improve maternal and fetal obstetrical outcomes.

Th1 or Th2 cytokines are correlated with Tregs and T cell subsets and pregnancy outcomes in patients with autoimmune thyroid disease during early, middle, late pregnancy, and postpartum period

Autoimmune thyroid disease (AITD) is a T lymphocytes-mediated autoimmune disorder affecting pregnant women. The current study sought to determine the correlations between T helper-1 (Th1)/T helper-2 (Th2) cytokines and regulatory T cells (Tregs) and T cell subsets and pregnancy outcomes in AITD patients during early pregnancy (T1), middle pregnancy (T2), late pregnancy (T3), and postpartum period (PP). A total of 60 patients with Graves' disease, 60 patients with Hashimoto's thyroiditis, and 30 healthy pregnant women were initially enrolled in the study. Thyroid hormones and antibodies, Th1 or Th2 cytokines, transforming growth factor-β, Tregs, CD4+ T helper cells (CD4+), CD8+ T helper cells (CD8+) levels were determined by means of Maglumi2000 automatic chemiluminescence instrument, enzyme-linked immunosorbent assay, and flow cytometry. Our findings demonstrated higher IFN-γ and IL-2 levels, along with lower IL-4, IL-10, TGF-β, Treg, and CD4+/CD8+ levels in AITD patients during T1, T2, T3, and PP. Furthermore, the TGF-β, Treg, and CD4+/CD8+ levels were lower in the IFN-γ/IL-2 high expression group but higher in the IL-4/IL-10 high expression group. The IFN-γ and IL-2 levels were higher, while IL-4 and IL-10 level were lower in AITD patients with adverse pregnancy outcomes. Lastly, Th1 cytokines were higher and Th2 cytokines were lower in AITD patients and elicited correlation with Tregs and CD4+/CD8+ levels. Collectively, our findings highlighted that up-regulation of Th1 cytokines may increase the percentage of adverse pregnancy outcomes in AITD patients.

Preconception Counseling in Patients with Hypothyroidism and/or Thyroid Autoimmunity

Preconception counseling is an essential tool for preventing adverse pregnancy outcomes associated with thyroid dysfunction. The high prevalence of thyroid disease among women of reproductive age, and the increased risk of adverse pregnancy outcomes associated with thyroid dysfunction, emphasize the necessity for well-established screening and treatment criteria in the preconception period. We therefore conducted a literature review for relevant information on the screening, diagnosis and treatment of subclinical and overt hypothyroidism in women seeking pregnancy. While screening for thyroid disease is recommended only in the presence of risk factors, iodine supplementation should be recommended in most regions, with higher doses in areas with severe deficiency. Known hypothyroid women should be counseled about increasing their levothyroxine dose by 20–30% in the case of suspected or confirmed pregnancy (missed menstrual cycle or positive pregnancy test). Treating subclinical hypothyroidism appears to be beneficial, especially in the presence of autoimmunity or in patients undergoing artificial reproductive techniques. Regarding the management of TPOAb negative SCH women or euthyroid women with positive TPOAb, further research is necessary in order to make evidence-based recommendations.

Levothyroxine in euthyroid thyroid peroxidase antibody positive women with recurrent pregnancy loss (T4LIFE trial): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Women positive for thyroid peroxidase antibodies (TPO-Ab) have a higher risk of recurrent pregnancy loss. Evidence on whether levothyroxine treatment improves pregnancy outcomes in women who are TPO-Ab positive women with recurrent pregnancy loss is scarce. The aim of this study was to determine if levothyroxine increases live birth rates in women who were TPO-Ab positive with recurrent pregnancy loss and normal thyroid function.

METHODS

The T4LIFE trial was an international, double-blind, placebo-controlled, phase 3 study done in 13 secondary and tertiary hospitals in the Netherlands, one tertiary hospital in Belgium, and one tertiary hospital in Denmark. Women (18-42 years) who were TPO-Ab positive, had two or more pregnancy losses, and had a thyroid stimulating hormone (TSH) concentration within the institutional reference range were eligible for inclusion. Women were excluded if they had antiphospholipid syndrome (lupus anticoagulant, anticardiolipin IgG or IgM antibodies, or β2-glycoprotein-I IgG or IgM antibodies), other autoimmune diseases, thyroid disease, previous enrolment in this trial, or contraindications for levothyroxine use. Before conception, women were randomly assigned (1:1) to receive either levothyroxine or placebo orally once daily. The daily dose of levothyroxine was based on preconception TSH concentration and ranged from 0·5-1·0 μg/kg bodyweight. Levothyroxine or placebo was continued until the end of pregnancy. The primary outcome was live birth, defined as the birth of a living child beyond 24 weeks of gestation measured in the intention-to-treat population. The trial was registered within the Netherlands Trial Register, NTR3364 and with EudraCT, 2011-001820-39.

RESULTS

Between Jan 1, 2013, and Sept 19, 2019, 187 women were included in the study: 94 (50%) were assigned to the levothyroxine group and 93 (50%) were assigned to the placebo group. The trial was prematurely stopped when 187 (78%) of the 240 predefined patients had been included because of slow recruitment. 47 (50%) women in the levothyroxine group and 45 (48%) women in the placebo group had live births (risk ratio 1·03 [95% CI 0·77 to 1·38]; absolute risk difference 1·6% [95% CI -12·7 to 15·9]). Seven (7%) women in the levothyroxine group and seven (8%) in the placebo group reported adverse events, none of them were directly related to the study procedure.

INTERPRETATION

Compared with placebo, levothyroxine treatment did not result in higher live birth rates in euthyroid women with recurrent pregnancy loss who were positive for TPO-Ab. On the basis of our findings, we do not advise routine use of levothyroxine in women who are TPO-Ab positive with recurrent pregnancy loss and normal thyroid function.

FUNDING

Dutch Organization for Health Research and Development, Fonds NutsOhra, Dutch Patient Organization of Thyroid Disorders, the Jan Dekkerstichting and Dr Ludgardine Bouwmanstichting, and a personal donation through the Dutch Patient Organization of Thyroid Disorders.