Positive Impact of Levothyroxine Treatment on Pregnancy Outcome in Euthyroid Women with Thyroid Autoimmunity Affected by Recurrent Miscarriage

The impact of gut microbiota on autoimmune thyroiditis and relationship with pregnancy outcomes: a review

Autoimmune thyroiditis (AITD) is a T-cell-mediated, organ- specific autoimmune disease caused by interactions between genetic and environmental factors. Patients with AITD show thyroid lymphocyte infiltration and an increase in the titer of thyroid autoimmune antibodies, thereby altering the integrity of thyroid follicle epithelial cells and dysregulating their metabolism and immune function, leading to a decrease in multi-tissue metabolic activity. Research has shown that patients with AITD have a significantly higher risk of adverse pregnancy outcomes, such as infertility and miscarriage. Levothyroxine(LT4) treatment can improve the pregnancy outcomes of normal pregnant women with thyroid peroxidase antibodies(TPOAb) positivity, but it is not effective for invitro fertilization embryo transfer (IVF-ET) in women with normal thyroid function and positive TPOAb. Other factors may also influence pregnancy outcomes of patients with AITD. Recent studies have revealed that the gut microbiota participates in the occurrence and development of AITD by influencing the gut-thyroid axis. The bacterial abundance and diversity of patients with Hashimoto thyroiditis (HT) were significantly reduced, and the relative abundances of Bacteroides, fecal Bacillus, Prevotella, and Lactobacillus also decreased. The confirmation of whether adjusting the composition of the gut microbiota can improve pregnancy outcomes in patients with AITD is still pending. This article reviews the characteristics of the gut microbiota in patients with AITD and the current research on its impact in pregnancy.

Raised First Trimester Thyroid Peroxidase Antibodies May Predict First Trimester Miscarriage: A Case Control Study

Miscarriages constitute a significant aspect of failed pregnancies and a source of worry for the patient and caregiver. Some of the causes of miscarriages remain unknown. Immunological conditions such as thyroid autoimmunity could play significant roles. Our objective was to determine the relationship between raised thyroid peroxidase antibodies and first trimester miscarriages in a low resource setting. This was a case control study at the Gynaecological Clinic of the University of Calabar Teaching Hospital, Nigeria; from 14th February 2020 to 13th January 2021, involving 145 cases who had first trimester miscarriages, and their matched controls who had apparently normal pregnancies, at same gestational ages. Sera of venous blood from both participants and controls were analysed for thyroid peroxidase antibodies using enzyme-linked immunosorbent assay, and analysed using SPSS version 20, and GraphPad Prism 8.4.3 statistical software. Being a civil servant and low social status had significant odds for first trimester miscarriage. Raised thyroid peroxidase antibodies in the first trimester had 10-fold odds for miscarriage. Odds ratio 10.34, 95% CI: 3.22 to 32.98, P-value = 0.0001. The test had a sensitivity of 89.66% and specificity of 54.41%. The positive predictive value was 17.93%, while the negative predictive value was 97.93% and a likelihood ratio of 1.966. Rising thyroid peroxidase antibodies in early pregnancy could be a predictor for miscarriage. This is so because patients with raised thyroid peroxidase antibodies in the first trimester had a 10-fold risk of having a first trimester miscarriage.

Effect of levothyroxine on the pregnancy outcomes in recurrent pregnancy loss women with subclinical hypothyroidism and thyroperoxidase antibody positivity: a systematic review and meta-analysis

OBJECTIVE

This study aimed to explore the effects of levothyroxine on pregnancy outcomes and thyroid function in recurrent pregnancy loss (RPL) women with subclinical hypothyroidism (SCH) or thyroperoxidase antibody positivity (TPOAb⁺).

METHODS

Literature search was performed from inception to 24 June 2022. The heterogeneity for each outcome was evaluated using Cochran's Q test and quantified with I-squared (I²). Pooled effect sizes were expressed as relative risk (RR) and weighted mean differences (WMD) with 95% confidence intervals (95% CIs). Stability of the results were assessed using the sensitivity analysis.

RESULTS

Fifteen eligible studies with 1911 participants were included in this meta-analysis. The pooled data showed that levothyroxine decreased premature delivery rate (RR = 0.48, 95%CI: 0.32, 0.72), miscarriage rate (RR = 0.59, 95%CI: 0.44, 0.79), premature rupture of membranes (PROM) rate (RR = 0.44, 95%CI: 0.29, 0.66), and fetal growth restriction rate (RR = 0.33, 95%CI: 0.12, 0.89) in RPL women with TPOAb⁺. In RPL women with SCH, live birth rate was elevated (RR = 1.20, 95%CI: 1.01, 1.42) and miscarriage rate was reduced (RR = 0.65, 95%CI: 0.44, 0.97) by levothyroxine. In addition, levothyroxine substantially decreased TSH level (WMD = -0.23, 95% CI: -0.31, -0.16) and TPO level (WMD = -23.48, 95%CI: -27.50, -19.47).

CONCLUSIONS

Levothyroxine improved pregnancy outcomes and thyroid function in RPL women with TPOAb⁺ or SCH, indicating that levothyroxine may be beneficial for RPL women if TPOAb⁺ or SCH occurs. Future studies are needed to verify our findings.

Treatment of recurrent pregnancy loss in women with euthyroid-based thyroid peroxidase antibody syndrome

Recurrent pregnancy loss (RPL) due to thyroid peroxidase antibody (TPOAb) syndrome remains a significant challenge in pregnancy. The current study offers better insights into miscarriages that occur due to the presence of TPOAb with euthyroid in pregnant women with a history of RPL. Out of the 347 women confirmed with unexplained RPL, only 70 (20.2%) tested positive for TPOAb (215±53). After eight women were excluded from the study due to failure to follow up, 62 participants (age range: 33±4.8 years; body mass index (BMI):25-30kg/m2 (58%) and >30kg/m2 (42%)) were included. The TPOAb-dependent RPL patients were divided according to their RPL types into 23 (30.7%) nulliparous (1˚) and 39 (69.3%) multiparous (2˚) patients, respectively. Out of the sample, 69.2% and 30.8% had a history of miscarriages during the 1st and 2nd trimesters, respectively. For treatment purposes, while screening for the TPOAb, the women received 50µg/day of L-thyroxine (LTx) for three months prior to pregnancy and during the first three months of pregnancy and were followed up until giving birth or miscarriage. Thyroxine treatment was correlated to successful normal births in 56.6% and 21.2% of pregnant women after 36 and during 28-36 weeks of gestation, respectively. However, miscarriages occurred in 18.1% and 4.1% of patients during 14-28 weeks and before 14 weeks of gestation, respectively. The current findings show the promising use of thyroxine in the control of RPL caused by euthyroid-based thyroid peroxidase antibody syndrome. This treatment has led to a significant number of women experiencing successful full-term pregnancies and giving birth to healthy babies.

The impact of levothyroxine therapy on pregnancy and neonatal outcomes in euthyroid pregnant women with thyroid autoimmunity: A systematic review, meta-analysis and trial sequential analysis

Background: At present, only one systematic review has investigated the effect of levothyroxine (LT4) in the treatment of euthyroid pregnant women with thyroid autoimmunity, but some problems [such as merging different types of research for meta-analysis, lacking neonatal outcomes, and so on] exist in this study, satisfactory results can not be provided. So, this systematic review was performed to investigate the effect of LT4 in euthyroid pregnant women with thyroid autoimmunity, in the hope of providing more comprehensive evidence for clinical use. Methods: Medline (Ovid), Embase (Ovid), and Cochrane Central Register of Controlled Trials were electronically searched from database inception to March 2022. We included cohort studies and RCTs that evaluated the impact of LT4 therapy on pregnancy and neonatal outcomes in euthyroid pregnant women with thyroid autoimmunity. Meta-analyses of different types of studies were performed separately, and meta-analyses were further performed by only including researches with low and moderate risk of bias. We used the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach to evaluate the quality of evidence, and used TSA to test the sufficiency of the evidence. Results: Finally, 2,901 euthyroid pregnant women with thyroid autoimmunity in six RCTs and five cohort studies were included. In all outcomes, no statistically significant differences were found between LT4 group and control group, including miscarriage [RR = 0.85, 95%CI (0.69,1.05), p = 0.14, I ² = 1%], preterm birth [RR = 0.80, 95%CI (0.59,1.08), p = 0.14, I2 = 0%], preeclampsia [RR = 0.68, 95%CI (0.12, 3.91), p = 0.66, I ² = 0%], placenta abruption [Peto' OR = 0.14, 95%CI (0.00, 6.94), p = 0.32, I ² = 0%], birth weight [MD = -36.00, 95%CI (-170.41, 98.41), p = 0.60, I ² = 0%], gestational age at delivery [MD = -0.10, 95%CI (-0.61, 0.41), p = 0.70, I ² = 0%] and neonatal admission [RR = 1.33, 95%CI (0.21, 8.58), p = 0.76, I ² = 0%]. The results for all outcomes were insufficient and inconclusive as demonstrated by TSA. The GRADE assessments showed that the quality of evidence of 4 outcomes (miscarriage, preterm birth, birth weight and gestational age at delivery) were moderate, and 3 outcomes (preeclampsia, placenta abruption and neonatal admission) were low or very low. Conclusion: For pregnancy and neonatal outcomes in euthyroid pregnant women with thyroid autoimmunity, we did not find benefit of LT4 treatment in this study. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022346745, identifier CRD42022346745.

Placental Dysfunction in Assisted Reproductive Pregnancies: Perinatal, Neonatal and Adult Life Outcomes

Obstetric and newborn outcomes of assisted reproductive technology (ART) pregnancies are associated with significative prevalence of maternal and neonatal adverse health conditions, such as cardiovascular and metabolic diseases. These data are interpreted as anomalies in placentation involving a dysregulation of several molecular factors and pathways. It is not clear which extent of the observed placental alterations are the result of ART and which originate from infertility itself. These two aspects probably act synergically for the final obstetric risk. Data show that mechanisms of inappropriate trophoblast invasion and consequent altered vascular remodeling sustain several clinical conditions, leading to obstetric and perinatal risks often found in ART pregnancies, such as preeclampsia, fetal growth restriction and placenta previa or accreta. The roles of factors such as VEGF, GATA3, PIGF, sFLT-1, sEndoglin, EGFL7, melatonin and of ART conditions, such as short or long embryo cultures, trophectoderm biopsy, embryo cryopreservation, and supraphysiologic endometrium preparation, are discussed. Inflammatory local conditions and epigenetic influence on embryos of ART procedures are important research topics since they may have important consequences on obstetric risk. Prevention and treatment of these conditions represent new frontiers for clinicians and biologists involved in ART, and synergic actions with researchers at molecular levels are advocated.