Subclinical hypothyroidism in the infertile female population: a guideline

The impact of thyroid autoimmunity on pregnancy outcomes in women with unexplained infertility undergoing intrauterine insemination: a retrospective single-center cohort study and meta-analysis

Introduction

Infertility affects 8-12% of couples worldwide, with 15-30% classified as unexplained infertility (UI). Thyroid autoimmunity (TAI), the most common autoimmune disorder in women of reproductive age, may impact fertility and pregnancy outcomes. However, the underlying mechanism is unclear. This study focuses on intrauterine insemination (IUI) and its potential association with TAI in UI patients. It is the first meta-analysis following a comprehensive literature review to improve result accuracy and reliability.

Methods

Retrospective cohort study analyzing 225 women with unexplained infertility, encompassing 542 cycles of IUI treatment. Participants were categorized into TAI+ group (N=47, N= 120 cycles) and TAI- group (N=178, N= 422 cycles). Additionally, a systematic review and meta-analyses following PRISMA guidelines were conducted, incorporating this study and two others up to June 2023, totaling 3428 IUI cycles.

Results

Analysis revealed no significant difference in independent variables affecting reproductive outcomes. However, comparison based on TAI status showed significantly lower clinical pregnancy rates (OR: 0.43, P= 0.028, 95%CI: 0.20-0.93) and live birth rate (OR: 0.20, P= 0.014, 95%CI: 0.05 ~ 0.71) were significantly lower than TAI- group. There was no significant difference in pregnancy rate between the two groups (OR: 0.61, P= 0.135, 95%CI: 0.32-1.17). However, the meta-analysis combining these findings across studies did not show statistically significant differences in clinical pregnancy rates (OR:0.77, P=0.18, 95%CI: 0.53-1.13) or live birth rates (OR: 0.68, P=0.64, 95%CI: 0.13-3.47) between the TAI+ and TAI- groups.

Discussion

Our retrospective cohort study found an association between TAI and reduced reproductive outcomes in women undergoing IUI for unexplained infertility. However, the meta-analysis incorporating other studies did not yield statistically significant associations. Caution is required in interpreting the relationship between thyroid autoimmunity and reproductive outcomes. Future studies should consider a broader population and a more rigorous study design to validate these findings. Clinicians dealing with women with unexplained infertility and TAI should be aware of the complexity of this field and the limitations of available evidence.

Impact of mildly evaluated thyroid-stimulating hormone levels on in vitro fertilization or intracytoplasmic sperm injection outcomes in women with the first fresh embryo transfer: a large study from China

PURPOSE

This study aimed to investigate the association between mild elevation of thyroid-stimulating hormone (TSH) levels and pregnancy outcomes of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatments in women with the first fresh embryo transfer.

METHODS

Large single-center retrospective cohort study of 15,728 patients from January 2018 to December 2022 were enrolled in the analyses. Clinical pregnancy rates, live birth rates, miscarriage rates, and ectopic pregnancy rates were compared between the TSH levels < 2.5 mIU/L group (N = 10,932) and TSH levels ≥ 2.5 mIU/L group (N = 4796). Subgroup analysis was performed for patients with TSH levels ≥ 2.5 mIU/L, dividing them into the thyroid peroxidase antibody (TPO)-negative group (N = 4524) and the TPO-positive group (N = 272).

RESULTS

There were no significant differences in the aforementioned pregnancy outcomes between the TSH levels < 2.5 mIU/L group and TSH levels ≥ 2.5 mIU/L group. Similarly, no significant differences were observed in the pregnancy outcomes between the TPO-negative group and the TPO-positive group.

CONCLUSION

Mildly elevated pre-conception TSH levels in thyroid-normal infertile patients did not have an impact on pregnancy outcomes of IVF/ICSI treatments.

Levothyroxine for a high-normal TSH in unexplained infertility

OBJECTIVE

Unexplained infertility affects nearly one-third of infertile couples. Women with unexplained infertility are more likely to have a high-normal thyroid-stimulating hormone level (TSH: 2.5-5 mIU/L) compared to women with severe male factor infertility. Practice guidelines vary on whether treatment should be initiated for TSH levels >2.5 mIU/L in women attempting conception because the effects of treating a high-normal TSH level with levothyroxine are not known. We evaluated conception and live birth rates in women with unexplained infertility and high-normal TSH levels.

DESIGN, PATIENTS AND MEASUREMENTS

Retrospective study including 96 women evaluated for unexplained infertility at a large academic medical centre between 1 January 2000 and 30 June 2017 with high-normal TSH (TSH: 2.5-5 mIU/L and within the normal range of the assay) who were prescribed (n = 31) or not prescribed (n = 65) levothyroxine. Conception and live birth rates were assessed.

RESULTS

The conception rate in the levothyroxine group was 100% compared to 90% in the untreated group (p = .086 unadjusted; p < .05 adjusted for age; p = .370 adjusted for TSH; p = .287 adjusted for age and TSH). The live birth rate was lower in the levothyroxine group (63%) compared to the untreated group (84%) (p = .05 unadjusted; p = .094 adjusted for age; p = .035 adjusted for TSH; p = .057 adjusted for age and TSH).

CONCLUSIONS

Women with unexplained infertility and high-normal TSH levels treated with levothyroxine had a higher rate of conception but lower live birth rate compared to untreated women, with the limitation of a small sample size. These findings assert the need for prospective, randomized studies to determine whether treatment with levothyroxine in women with unexplained infertility and high-normal TSH is beneficial.

Expanding the role of chromosomal microarray analysis in the evaluation of recurrent pregnancy loss

Multiple factors contribute to recurrent pregnancy loss (RPL). This review highlights the latest international guidelines for RPL workup, including immunological testing, by the American Society for Reproductive Medicine (ASRM), the European Society of Human Reproduction and Embryology (ESHRE), and the Royal College of Obstetricians and Gynaecologists (RCOG). These three societies recommend testing for antiphospholipid syndrome. ESHRE and RCOG also recommend thyroid peroxidase antibody testing, whereas ASRM does not. All guidelines advise against testing of natural killer cells, cytokines, antinuclear antibodies, human leukocyte antigen (HLA) compatibility, anti-HLA antibodies, and anti-sperm antibodies. However, when following ASRM, ESHRE or RCOG diagnostic guidelines, over 50% of cases have no identifiable cause. Genetic testing of products of conception (POC) can improve our understanding of unexplained RPL as aneuploidy is a common cause of RPL. Based on studies reporting results from chromosomal microarray analysis (CMA) of POC, we propose a novel algorithm for RPL evaluation. The algorithm involves following evidence-based societal guidelines (published by ASRM, ESHRE, or RCOG), excluding parental karyotyping, in combination with CMA testing of miscarriage tissue. When utilizing this new evaluation algorithm, the number of unexplained cases of RPL decreases from over 50% to less than 10%. As a result, most patients are provided an explanation for their loss and healthcare costs are potentially reduced. Patients with an otherwise negative workup with euploid POC, are classified as "truly unexplained RPL". These patients are excellent candidates for enrollment in randomized, controlled trials examining novel immunological testing and treatment protocols.

Pregnancy outcomes following ultrasound-guided high-intensity focused ultrasound in submucous leiomyomas: a retrospective study

OBJECTIVE

To investigate the impact of ultrasound-guided high-intensity focused ultrasound (USgHIFU) on pregnancy in submucous leiomyomas.

MATERIALS AND METHODS

Between October 2015 and October 2021, a retrospective observational study was conducted at the Affiliated Hospital of North Sichuan Medical College, China, for 32 women with submucous leiomyomas who became pregnant after USgHIFU. Pregnancy outcomes, submucous leiomyomas characteristics, and USgHIFU parameters were analyzed.

RESULTS

A total of 17 (53.1%) deliveries were successfully achieved, with full-term delivery in 16 (94.1%) patients and preterm delivery in 1 (5.9%). After USgHIFU, the effective volume in the uterus cavity and the volume of submucous leiomyomas shrank in all 32 patients. The median time to achieve pregnancy after USgHIFU was 11.0 months. Before pregnancy, myoma type was downgraded in 13 (40.6%) patients, stable in 10 (31.3%) and upgraded in 9 (28.1%). The vaginal expulsion rate of submucous leiomyomas was 28.1%, with complete expulsion in 3 (9.4%) patients and partial expulsion in 6 (18.8%). After USgHIFU, the size of submucous leiomyomas did not increase in each trimester (all p > 0.05). The high complications rate during pregnancy (7/17, 41.2%) was associated with advanced maternal age, with only one (5.9%) premature rupture of membranes possibly associated with submucous leiomyomas. There were 6 (35.5%) vaginal delivery and 11 (64.7%) cesarean sections. All 17 newborns developed well, with a mean birth weight of 3482 g.

CONCLUSIONS

In patients with submucous leiomyomas, pregnancies and full-term deliveries can be successfully achieved following USgHIFU, with few related complications.

Effect of extra-low dose levothyroxine supplementation on pregnancy outcomes in women with subclinical hypothyroidism undergoing in vitro fertilization and embryo transfer

OBJECTIVE

This study was undertaken to test the therapeutic effect of extra-low dose of levothyroxine (LT4; 25 mcg/day) to preconception and pregnant women with subclinical hypothyroidism (SCH).

MATERIALS AND METHODS

This is a retrospective study, SCH women who succeeded in their first in vitro fertilization (IVF) cycle between January 1, 2018, to December 31, 2020 were included. SCH is defined as normal serum free thyroxine (T4) level and an elevated serum thyroid stimulating hormone (TSH) level >4 mIU/L. Extra-low dose of levothyroxine (LT4; 25 mcg/day) was prescribed to the SCH women from the establish of diagnosis of SCH to the end of pregnancy. The pregnancy outcomes (miscarriage, live birth, preterm birth, and small for gestational age baby) were compared to the euthyroid pregnant women.

RESULTS

Totally, 589 women were screened, and 317 cases received their first time IVF treatment. 167 women were clinically pregnant after IVF treatment, 155 of them were euthyroid and 12 of these women were diagnosed to have SCH. The average age of the participants was 35 years old. There were no significant differences in age, body mass index (BMI), anti-müllerian hormone (AMH), types of embryo transfer, number of embryos to transfer, or embryo stage during transfer between two groups. The live birth rate, miscarriage rate, and preterm birth rate in women with SCH supplemented with extra-low dose of LT4 were non-inferior to euthyroid patients (miscarriage rate: P = 0.7112; live birth rate: P = 0.7028; preterm delivery: P = 0.2419; small for gestational age: P = 0.2419).

CONCLUSION

Our result demonstrated that supplementation with extra-low dose of levothyroxine at 25 mcg/day to SCH women can produce the comparable obstetrical and neonatal outcome as that in euthyroid pregnant women. Accordingly, we suggest extra-low-dose of levothyroxine may be considered as a safe and effective alternative for those SCH pregnant women who were not tolerated to the standard dose of levothyroxine.

In infertile women with subclinical hypothyroidism, with or without thyroid peroxidase antibodies, serum TSH during pregnancy follows preconception values and thyroid hormones remain stable

STUDY QUESTION

How does subclinical hypothyroidism, defined in infertile women during preconception by thyroid-stimulating hormone (TSH) >2.5 or >4.5 mIU/l, with or without thyroid peroxidase antibodies (anti-TPO) >100 IU/ml, impact thyroid hormone levels during pregnancy and after birth?

SUMMARY ANSWER

During pregnancy, TSH levels remain similar to those in preconception, even with supplementary thyroxine, whereas the serum levels of anti-TPO progressively decline.

WHAT IS KNOWN ALREADY

Overt hypothyroidism impacts both pregnancy and offspring but randomized clinical trials and cohort studies failed to detect the benefit of treatment with thyroxine in cases with low-threshold TSH or with anti-TPO during pregnancy.

STUDY DESIGN SIZE DURATION

First, the prevalence and reproducibility of two candidate cut-off levels of subclinical hypothyroidism in a cohort of 177 infertile women was compared with 171 women not aiming for pregnancy. Second, the impact of distinct setpoints of TSH in preconception (with or without anti-TPO) was monitored during pregnancy in 87 previously infertile women by high-frequency monitoring of thyroid function. Both studies were carried out from 2007 to 2019.

PARTICIPANTS/MATERIALS SETTING METHODS

Reproducibility and prevalence of subclinical hypothyroidism were examined in infertile women presenting in the fertility care unit of an academic institution. Women not aiming for pregnancy participated as controls. In both groups, TSH and anti-TPO were measured two times on different occasions. In addition, a group of previously infertile women with known preconception setpoints of TSH (with or without anti-TPO) were followed up prospectively throughout pregnancy and after birth. During pregnancy, serum was sampled weekly until Week 12, then monthly until delivery, and once after birth. Only cases with preconception TSH >4.5 mIU/l were supplemented with thyroxine. After collection of all samples, the serum levels of anti-TPO and the major thyroid hormones were measured. Prolactin with known fluctuations during pregnancy was used as reference.

MAIN RESULTS AND THE ROLE OF CHANCE

Measures of both TSH and anti-TPO at two different time points were accurate and reproducible. The odds of subclinical hypothyroidism in infertile women and controls were similar. During pregnancy, TSH closely followed preconception TSH levels, whereas serum levels of the thyroid hormones predominantly remained within or above (not below) the reference. Treatment of infertile women with preconception TSH >4.5 mIU/l with thyroxine resulted in higher free thyroxine (fT4) serum levels. The serum levels of anti-TPO declined as pregnancies evolved.

LIMITATIONS REASONS FOR CAUTION

The numbers of participants both in the prevalence study and in pregnancy did not reach the a priori estimated numbers. For ethical reasons, the patients with preconception TSH >4.5 mIU/l were treated with thyroxine. The findings apply to infertile women only.

WIDER IMPLICATIONS OF THE FINDINGS

We propose to use >4.5 mIU/l as the serum TSH threshold for supplementing women with thyroxine before pregnancy. During pregnancy, fT4 may be the better marker to monitor thyroid function. The consistent decrease of anti-TPO antibody levels during ongoing pregnancies must be considered a protective element.

STUDY FUNDING/COMPETING INTERESTS

The prevalence part of this study was supported by Merck-Serono, Geneva (TH006/EMR200007-603). The hormone measurements of the serum samples collected during the follow-up pregnancies were made possible by financial support of Roche Diagnostica (November 1721, 2017, Rotkreuz, Switzerland). I.D.G. was supported by a grant of the Repronatal Foundation, Basel, Switzerland. All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

Research Database of UniBasel, project no. 576691 (2007).

Subfertility as Overlapping of Nutritional, Endocrine, Immune, and Cardiometabolic Dysregulations-A Study Focused on Biochemical Endophenotypes of Subfertile Couples

Subfertility is a global health issue, and as many as 30% of cases are attributed to unexplained reasons. A hypercaloric, high-fat diet stimulates the expansion of pro-inflammatory gut microbiota with a consequent rise in circulating lipopolysaccharides. Adverse gut microbiota remodeling can exacerbate insulin resistance, while sex and thyroid hormones may influence the variability in gut microbiota. This cross-sectional study included 150 participants and was designed to determine a biochemical, nutritional-related pattern that may distinguish subfertile from fertile individuals and couples. A panel of 28 biomarkers was assessed. Four biochemical phenotypes of unexplained subfertility were found, including two metabolic and two immune, when assessed using binary logistic regression models. Two phenotypes were distinguished in women: cardio-metabolic with atherogenic dyslipidemia (LowHDL-cholesterol: OR = 10.9; p < 0.05) and autoimmune thyroid disorder (Highanti-thyroid-peroxidase: OR = 5.5; p < 0.05) and two in men: hepato-metabolic with elevated liver injury enzymes (HighHOMA-IR: OR = 6.1; p < 0.05) and immune type-2 response (HighIgE: OR = 6.4; p < 0.05). The chances of a couple's subfertility rose with the number of laboratory components of metabolic syndrome in the couple (OR = 1.7; p < 0.05) and if at least one partner had an elevated total IgE level (>100 kU/L) (OR = 6.5; p < 0.05). This study found that unexplained subfertility may be accompanied by mutually overlapping immune and metabolic dysregulations in individuals and couples. We propose one-time laboratory diagnostics taking into account the lipid profile, insulin resistance, anti-thyroid-peroxidase, and total IgE in both males and females with unexplained subfertility. This may allow for a one-time assessment of targeted medical and nutritional interventions and help optimize patients' health. The gut-organ axes related to subfertility are discussed in the context of the obtained results.

Endocrine factors associated with infertility in women: an updated review

INTRODUCTION

Infertility is defined as the inability to conceive after unprotected sexual intercourse for at least 12 consecutive months. Our objective is to present an updated narrative review on the endocrine causes of infertility in women.

AREAS COVERED

A comprehensive review was conducted using Scielo, Scopus, and EMBASE databases, comprising 245 articles. The pathophysiology of infertility in women was described, including endocrinopathies such as hypothalamic amenorrhea, hyperprolactinemia, polycystic ovary syndrome, primary ovarian insufficiency, obesity, thyroid dysfunction, and adrenal disorders. The diagnostic approach was outlined, emphasizing the necessity of hormonal studies and ovarian response assessments. Additionally, the treatment plan was presented, commencing with non-pharmacological interventions, encompassing the adoption of a Mediterranean diet, vitamin supplementation, moderate exercise, and maintaining a healthy weight. Subsequently, pharmacological treatment was discussed, focusing on the management of associated endocrine disorders and ovulatory dysfunction.

EXPERT OPINION

This comprehensive review highlights the impact of endocrine disorders on fertility in women, providing diagnostic and therapeutic algorithms. Despite remaining knowledge gaps that hinder more effective treatments, ongoing research and advancements show promise for improved fertility success rates within the next five years. Enhanced comprehension of the pathophysiology behind endocrine causes and the progress in genetic research will facilitate the delivery of personalized treatments, thus enhancing fertility rates.

Impact of thyroid autoantibodies and serum TSH level on clinical IVF outcomes

OBJECTIVE

This study aimed to investigate the impact of thyroid autoantibodies and serum TSH levels on clinical IVF outcomes.

MATERIALS AND METHODS

This study included 260 Korean women scheduled for their first IVF between 2013 and 2017. Serum levels of thyroid hormone, TSH, and antibody for thyroid peroxidase and thyroglobulin were measured just before the first ovarian stimulation. Clinical pregnancy rate (PR), ongoing PR, and miscarriage rate were analyzed according to thyroid autoimmunity and serum TSH levels. The primary outcome was ongoing PR beyond 12 weeks of gestation.

RESULTS

The ongoing PR and miscarriage rates were similar between women with positive (n = 29) and negative autoantibodies (n = 186). In women with subclinical hypothyroidism (serum TSH ≥4.2 μIU/mL), ongoing PR was significantly lower than euthyroid women (22.2%, vs. 44.7%, p = 0.045), but miscarriage rate was similar. The group with serum TSH ≥3.4 μIU/mL showed a significantly lower ongoing PR (23.9% vs. 46.7%, p = 0.005) and significantly higher miscarriage rate (38.9% vs. 14.1%, p = 0.020). In multivariate logistic regression analysis, serum TSH ≥3.4 μIU/mL was an independent unfavorable predictor for ongoing PR (odds ratio 0.375, p = 0.013).

CONCLUSION

Thyroid autoantibodies did not affect clinical IVF outcomes, but women with serum TSH ≥3.4 μIU/mL demonstrated poor IVF outcomes.

Relationship between thyroid antibody levels and ovarian reserve function in infertile chinese women with normal thyroid-stimulating hormone

BACKGROUND

To analyze the relationship of thyroid peroxidase antibody and thyroid globulin antibody levels with ovarian reserve function in infertile women.

METHODS

The data of 721 infertile patients who visited the hospital from January 2019 to September 2022 and whose thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were in the normal range, were retrospectively analyzed. These patients were divided into two sets of three groups-the negative group, the 2.6 IU/ml ~ 100 IU/ml group and the TPOAb > 100 IU/ml group according to the TPOAb (thyroid peroxidase antibody) level, or the TgAb (anti-thyroglobulin antibody) negative group, the 14.58 IU/ml ~ 100 IU/ml group and the TgAb > 100 IU/ml group according to the TgAb level. They were compared for differences in ovarian reserve function index and thyroid hormone levels and analyzed for the relationship among thyroid antibody levels, ovarian reserve function, and thyroid hormone levels.

RESULTS

When TSH > 2.5 mIU/L, the bFSH (basal follicle stimulating hormone) level in the TPOAb > 100 IU/ml group (9.10 ± 1.16 IU/L) was significantly higher than that in the TPOAb negative group (8.12 ± 1.97 IU/L) and the 2.6 IU/ml ~ 100 IU/ml group (7.90 ± 1.48 IU/L) (P < 0.05); when TSH ≤ 2.5 mIU/L, there were no statistically significant differences in the bFSH and AFC (antral follicle count) number at different TPOAb levels. Whether TSH ≤ 2.5 mIU/L or TSH > 2.5 mIU/L, there were no statistically significant differences in the bFSH and AFC number at different TgAb levels (P > 0.05). FT3/FT4 ratio in the TPOAb 2.6 IU/ml ~ 100 IU/ml group and the > 100 IU/ml group was significantly lower than in the negative group. FT3/FT4 ratio in the TgAb 14.58 ~ 100 IU/ml group and the > 100 IU/ml group was also significantly lower than in the TgAb negative group (P < 0.05). TSH level in the TPOAb > 100 IU/ml group was significantly higher than in the 2.6 ~ 100 IU/ml group and the TPOAb negative group, but there were no statistically significant differences among different TgAb groups.

CONCLUSIONS

When TPOAb > 100 IU/ml and TSH > 2.5 mIU/L, it may affect the ovarian reserve function in infertile patients, and the mechanism may be associated with increased TSH and the imbalance of FT3/FT4 ratio caused by the increase of TPOAb.

Impact of thyroid autoimmunity on pregnancy outcomes in euthyroid women following fresh/frozen-thawed embryo transfer

OBJECTIVE

To investigate whether thyroid autoimmunity (TAI) is associated with assisted reproductive technology (ART) outcomes in euthyroid women undergoing fresh embryo transfer (ET) and frozen-thawed embryo transfer (FET).

DESIGN

A retrospective cohort study. Pregnancy and neonatal outcome after fresh ET or FET were compared between the positive and negative thyroid autoimmune antibody groups.

PATIENTS

A total of 5439 euthyroid women who started their ART cycle at our centre between 2015 and 2019 were included.

RESULTS

The thyroid antibody positive group had a greater mean age than the thyroid antibody negative group (32(29,35) vs. 31(28,34), p < .001). Women with positive thyroid antibody presented with a higher prevalence of diminished ovarian reserve (DOR) (9.1% vs. 7.1%, p = .026) and lower number of oocyte retrieved (9(5,15) vs. 10(6,15), p = .020), but difference was not significant after adjusting for age. The pregnancy rate, live birth rate, pregnancy loss rate, preterm delivery rate and low birthweight rate between the thyroid antibody positive and thyroid antibody negative groups were comparable both in fresh ET cycles and FET cycles. Subanalysis of the treatment outcomes when using a stricter threshold of TSH of 2.5 mIU/L showed no difference to that achieved when using an upper limit of 4.78 mIU/L.

CONCLUSIONS

The present study reveals that patients with anti-thyroid peroxidase antibodies (TPOAbs) and/or antithyroglobulin antibodies (TgAbs) showed no significant differences in pregnancy outcomes following fresh ET and FET when compared with patients with negative thyroid antibodies.

Impact of preconception thyrotrophin on obstetric outcomes in the fertile population

INTRODUCTION

There is evidence that subclinical hypothyroidism is associated with infertility, miscarriage and obstetric complications. However, there is controversy regarding the optimal TSH value in women seeking pregnancy. Current guidelines recommend that hypothyroid women with levothyroxine replacement who are planning pregnancy should optimise the dose of levothyroxine to achieve thyrotrophin (TSH) levels <2.5 mU/l, since these requirements increase in pregnancy, thus reducing the risk of TSH elevation during the first trimester. In women with infertility, who undergo highly complex treatments and have positive thyroid autoimmunity, values of TSH <2.5 mU/l prior to fertility treatment are suggested. Although this is a different population, these «optimal» TSH levels were also extended to euthyroid women without evidence of infertility, who are seeking pregnancy.

OBJECTIVES

Determine whether preconception TSH levels between 2.5 and 4.64 mIU/l are associated with adverse obstetric outcomes in euthyroid women.

MATERIALS AND METHODS

Retrospective cohort study. We evaluated 3265 medical records of pregnant women aged 18-40 years, euthyroid (TSH 0.5-4.64 mU/ml), with TSH measurement at least one year before gestation. 1779 met inclusion criteria. The population was divided according to categories: TSH 0.5-2.4 mU/l (optimal) and TSH 2.5-4.6 mU/l (suboptimal). Information on maternal and fetal obstetric outcomes was collected from each group.

RESULTS

We found no statistical difference in the occurrence of adverse obstetric events between the two groups. There was also no difference when adjusting for thyroid autoimmunity, age, body mass index, previous diabetes and previous arterial hypertension.

CONCLUSION

Our results suggest that the reference range of TSH used in the general population could be used in women seeking pregnancy, even in the presence of thyroid autoimmunity. Treatment with levothyroxine should be considered only in patients with special situations.

Comparison of reproductive outcomes in subclinical hypothyroidism women with high-normal versus low-normal thyroid-stimulating hormone levels after treatment with levothyroxine

OBJECTIVE

Reproductive outcomes in euthyroid women with high-normal thyroid-stimulating hormone (TSH) levels are comparable to those in euthyroid women with low TSH levels; however, few studies have investigated whether strictly controlled TSH levels after levothyroxine (LT4) treatment impair reproductive outcomes in infertile women with subclinical hypothyroidism (SCH). This study aimed to investigate the impact of high-normal versus low-normal TSH levels on reproductive outcomes in women undergoing their first in vitro fertilisation and embryo transfer (IVF-ET) cycle.

DESIGN

This was a retrospective cohort study. Patients were divided into low-normal (TSH < 2.5 mIU/L, and ≥0.27 mIU/L) and high-normal (TSH ≥ 2.5 mIU/L, and <4.2 mIU/L) groups based on TSH levels after LT4 treatment. TSH levels after LT4 treatment and before ovarian stimulation were recorded. Reproductive outcomes were compared between the low-normal and high-normal TSH groups and between the euthyroid and LT4-treated groups.

RESULTS

A total of 6002 women, 548 of whom were LT4-treated women, were finally included in this study. Among the LT4-treated women, 129 women had low-normal TSH levels, and 167 women had high-normal TSH levels. The clinical pregnancy rate, miscarriage rate, and live birth rate were comparable between the low-normal and high-normal groups (all p > .05). When adjusted by age, anti-Mullerian hormone (AMH) levels, infertility duration, transferred embryos, and dose and duration of LT4 treatment, high-normal TSH levels neither significantly decreased miscarriage (adjusted odds ratio [aOR] = 2.27, 95% confidence interval [CI] = 0.77-6.69, p = .14) nor increased clinical pregnancy (aOR = 1.15, 95% CI = 0.70-1.89, p = .57 or live birth (aOR = 0.97, 95% CI = 0.60-1.59, p = .92). Similar obstetric outcomes were observed between the low-normal and high-normal TSH groups after LT4 treatment and between the euthyroid and LT4-treated groups (all p ≥ .05).

CONCLUSIONS

High-normal TSH levels did not have adverse effects on clinical and obstetric outcomes when compared with low-normal TSH levels after LT4 treatment. However, whether it is appropriate to set 2.5 mIU/L as the goal of treatment before IVF/ICSI remains to be determined in further well-designed studies.

The role of thyroid function in female and male infertility: a narrative review

PURPOSE

We herein aimed to review the new insights into the impact of impaired thyroid function on male and female fertility, spacing from spontaneous pregnancy to ART, with the objective of providing an updated narrative revision of the literature.

METHODS

This narrative review was performed for all available prospective, retrospective and review articles, published up to 2021 in PubMed. Data were extracted from the text and from the tables of the manuscript.

RESULTS

Thyroid dysfunction is frequently associated with female infertility, whereas its link with male infertility is debated. Female wise, impaired function is detrimental to obstetric and fetal outcomes both in spontaneous pregnancies and in those achieved thanks to assisted reproduction technologies (ART). Furthermore, the reference range of TSH in natural pregnancy and ART procedures has recently become a matter of debate following recent reports in this field. On the other hand, the impact of thyroid function on the male reproductive system is less clear, although a possible role is suggested via modulation of Sertoli and Leydig cells function and spermatogenesis.

CONCLUSION

Thyroid function should be carefully monitored in both male and female, in couples seeking spontaneous pregnancy as well as ART, as treatment is generally immediate and likely to improve chances of success.

Management of recurrent implantation failure: British Fertility Society policy and practice guideline

Recurrent implantation failure (RIF) is defined as the absence of a positive pregnancy test after three consecutive transfers of good quality embryos. There remains significant variation in clinical practice in the management of RIF. This British Fertility Society (BFS) Policy and Practice guideline analyses the evidence for investigations and therapies that are employed in RIF and provides recommendations for clinical practice and for further research. Evidence for investigations of sperm and egg quality, uterine and adnexal factors, immunological factors and thrombophilia, endocrine conditions and genetic factors and for associated therapies have been evaluated. This guideline has been devised to assist reproductive medicine specialists and patients in making shared decisions concerning management of RIF. Finally, suggestions for research towards improving understanding and management of RIF have also been provided.

Effects of Levothyroxine Therapy on Pregnancy and Neonatal Outcomes in Subclinical Hypothyroidism

Purpose

To assess the effects of levothyroxine (LT4) therapy on pregnancy and neonatal outcomes in pregnant women with subclinical hypothyroidism (SCH) who had different thyroid peroxidase antibody (TPOAb) status.

Methods

The data of pregnant women from the Chengdu Hospital of Integrated Traditional Chinese and Western Medicine between January 2017 and August 2019 were collected. SCH was defined as 11.88 < free thyroxine (FT4) < 20.06pmol/L in conjunction with thyroid-stimulating hormone (TSH) >4.00 mU/L. Some clinical characteristics have been collected, including body mass index (BMI) before pregnancy, number of pregnancies, number of miscarriages (spontaneous abortion), parity, family history of diabetes, history of smoking, history of drinking, TSH, FT4, and TPOAb levels. The prevalence of pregnancy and neonatal outcomes in the LT4 and non-LT4 groups, and in the LT4 and euthyroid control groups were compared, respectively. Univariate and multivariate logistic regression analyses were used to assess the effects of LT4 therapy on pregnancy and neonatal outcomes in SCH pregnant women with TPOAb.

Results

A total of 985 subjects were enrolled and divided into LT4 group with 478 patients, non-LT4 group with 156 patients and euthyroid control group with 351 patients. The prevalence of amniotic fluid abnormalities and premature delivery in the LT4 group was lower than that in the non-LT4 group in participants with TPOAb-positive (TPOAb⁺). After adjusting age, BMI prior to pregnancy, number of pregnancies, number of miscarriages, parity, TSH and FT4 level, the SCH pregnant women with TPOAb⁺ in the LT4 group had a lower risk of amniotic fluid abnormalities and premature delivery than that in the non-LT4 group.

Conclusion

LT4 therapy could reduce the risk of premature delivery and amniotic fluid abnormalities in the SCH pregnant women with TPOAb⁺. However, more randomized trials are required to confirm this association before the unequivocal advocacy of LT4 therapy in pregnant women with SCH.

Effect of TSH on oocyte maturation of PCOS patients with normal thyroid function in IVF

BACKGROUND

The serum TSH level of PCOS patients was higher than that of the general female population. For patients with thyroid dysfunction, the abnormal TSH level is negatively related to the outcomes of assisted reproductive technology, but for PCOS patients with normal thyroid function, the effect of TSH level on outcomes of in vitro fertilization has not been reported. In this study, PCOS patients with normal thyroid function were included in this study to evaluate the effect of TSH on the outcomes of IVF-ET.

METHODS

A retrospective cohort study was conducted to analyze the clinical data of 3190 patients who underwent IVF-ET in the Department of Human Reproductive Center of Renmin Hospital Hubei University of Medicine from January 2017 to July 2021, including 594 PCOS patients and 2595 non PCOS patients. The IVF-ET outcomes between the two groups were compared; Multi-factor linear regression analysis was used to analyze the correlation between the related variables and the oocyte maturation of PCOS patients; The ROC curve of the effect of TSH on oocyte maturation in PCOS patients was drawn. The PCOS patients were divided into TSH < 2.98 group (n = 454) and TSH ≥ 2.98 group (n = 141) according to ROC threshold TSH 2.98, and the outcomes were compared.

RESULTS

TSH level in PCOS group was significantly higher than that in non-PCOS group (2.42 ± 0.86 vs 2.00 ± 0.89 UU / ml, P < 0.01), and the oocyte maturation rate and 2PN fertilization rate in PCOS group were lower than those in non-PCOS group (90.9% vs 92.4%, P = 0.02) (84.57% vs 86.77%, P = 0.02). There was no significant difference in cleavage rate and high-quality embryo rate between the two groups (P > 0.05); There was no difference in clinical pregnancy rate, abortion rate, ectopic pregnancy rate and live birth rate between the two groups (P > 0.05). Multi-factor linear regression analysis showed that TSH was negatively correlated with oocyte maturation in PCOS patients [β = -0.124, P = 0.013,95%CI (-0.027 ~ -0.003)]; The oocyte maturation rate in TSH < 2.98 group was significantly higher than that in TSH ≥ 2.98 group (91.7% vs 88.2%, P = 0.001).

CONCLUSION

The TSH level of PCOS patients with normal thyroid function is higher than that of normal people, and it is negatively correlated with the oocyte maturation in in-vitro fertilization. The ROC curve showed that when TSH > 2.98uIU/ml, the possibility of immature oocytes was higher (specificity 28.9%, sensitivity 83.0%).

Evaluation of the relationship between serum TSH levels and pregnancy outcomes of IVF/ICSI patients in follicular phase long-acting long protocol

ObjectiveTo investigate whether TSH levels are associated with the pregnancy outcomes of patients in the follicular phase long-acting long protocol of IVF/ICSI.MethodsThis was a single-central, retrospective study which was conducted in the Reproductive Medicine Center, Renmin Hospital of Wuhan University from February 2019 to April 2021. A total number of 773 patients underwent the follicular phase long-acting long protocol during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment were divided into Group A (0.5 mIU/L ≤ TSH ≤2.5 mIU/L, n = 463) and Group B (2.5 mIU/L < TSH≤ 4.5 mIU/L, n = 310) according to their serum TSH levels. The clinical data and pregnancy outcomes were compared between the two groups. The possible relationship between TSH levels and pregnancy outcomes in people who performed follicular phase long-acting long protocol was investigated.ResultsThe proportion of patients with infertility due to ovulation disorders was significantly greater in Group B than in Group A (p = 0.036). The duration of Gn of Group B was significantly longer than that of Group A (p = 0.001). The Gn dose of Group B was significantly larger than that of Group A (p = 0.002). Besides, the implantation rate and miscarriage rate of embryos transferred on D3 were significantly higher in Group B than that of Group A (p = 0.033, p = 0.026 respectively).ConclusionsThe higher implantation and miscarriage rates of D3 of IVF/ICSI in the follicular phase long-acting long protocol may be related to higher serum TSH levels.

The relationship between TSH levels and clinical pregnancy outcomes for patients who undergo in vitro fertilization/intracytoplasmic sperm injection: a retrospective study

BACKGROUND

Thyroid dysfunction is linked with adverse pregnancy outcomes, an upper limit of a normal thyroid-stimulating hormone (TSH) threshold of 4.12-4.5 mIU/L should be considered for subclinical hypothyroidism in the infertile female population. Whereas, it's controversial whether or not the infertility thresholds for upper limit of TSH threshold of 2.5 mIU/L. In our study examines the correlation of optimal TSH levels and clinical pregnancy outcomes after fresh in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) embryo transfer cycles.

METHODS

Patients who underwent fresh IVF/ICSI embryo transfer cycles for the first time who presented between January 1, 2015 and December 31, 2017 at the Chongqing Institute of Reproductive and Genetic, Chongqing Health Center for Women and Children were enrolled. We excluded patients with ≥40 years, body mass index (BMI) ≤18 or ≥28 kg/m², the man with severe oligoasthenospermia, women with poor ovarian reserve, and presence of endocrine disorders, uterine anomaly, sactosalpinx, abnormal thyroid function, preimplantation genetic diagnosis, and chromosomal abnormality or polymorphism. Baseline characteristics and clinical pregnancy outcomes were observed in our study. We detected between TSH levels and clinical pregnancy outcomes in patients undergoing IVF/ICSI by Receiver operating characteristic (ROC) curves and logical regression.

RESULTS

A total of 6,088 patients who undergo IVF/ICSI were included. We first detected that the live birth rate had a statistically significant difference when the TSH level was 3 mIU/L. With the TSH ≤3 mIU/L group having a higher live birth rate than the TSH >3 mIU/L group (51.79% vs. 47.89%, P=0.024), meanwhile no significant difference were revealed between the early miscarriage rate (12.54% vs. 14.97%, P=0.091) and early clinical pregnancy rate (59.21% vs. 56.32%, P=0.114). There were no differences in pregnancy outcomes when the TSH threshold was at 3.5 or 4 mIU/L and no association was detected between TSH levels and clinical pregnancy outcomes in patients undergoing IVF/ICSI by ROC curves and logical regression.

CONCLUSIONS

Patients undergoing IVF/ICSI with a serum TSH level ≤3 mIU/L may have a higher live birth rate rather than ≤2.5 or ≤4 mIU/L.

Hypothyroidism

Hypothyroidism is the common clinical condition of thyroid hormone deficiency and, if left untreated, can lead to serious adverse health effects on multiple organ systems, with the cardiovascular system as the most robustly studied target. Overt primary hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) concentration in combination with free thyroxine (fT₄) concentration below the reference range. Subclinical hypothyroidism, commonly considered an early sign of thyroid failure, is defined by elevated TSH concentrations but fT₄ concentrations within the reference range. Hypothyroidism is classified as primary, central or peripheral based on pathology in the thyroid, the pituitary or hypothalamus, or peripheral tissue, respectively. Acquired primary hypothyroidism is the most prevalent form and can be caused by severe iodine deficiency but is more frequently caused by chronic autoimmune thyroiditis in iodine-replete areas. The onset of hypothyroidism is insidious in most cases and symptoms may present relatively late in the disease process. There is a large variation in clinical presentation and the presence of hypothyroid symptoms, especially in pregnancy and in children. Levothyroxine (LT4) is the mainstay of treatment and is one of the most commonly prescribed drugs worldwide. After normalization of TSH and fT₄ concentrations, a considerable proportion of patients treated with LT4 continue to have persistent complaints, compromising quality of life. Further research is needed regarding the appropriateness of currently applied reference ranges and treatment thresholds, particularly in pregnancy, and the potential benefit of LT4/liothyronine combination therapy for thyroid-related symptom relief, patient satisfaction and long-term adverse effects.

Management of Hypothyroidism and Hypothyroxinemia in Pregnancy

OBJECTIVE

To review the diagnosis and management of hypothyroidism in pregnancy, preconception, and the postpartum period.

METHODS

Literature review of English-language papers published between 1982 and 2022, focusing on the most recent literature.

RESULTS

During pregnancy, thyroid function laboratory tests need to be interpreted with regard to gestational age. Overt hypothyroidism, regardless of the TSH level, should always be promptly treated when it is diagnosed preconception or during pregnancy or lactation. Most women with preexisting treated hypothyroidism will require an increase in levothyroxine dosing to maintain euthyroidism during gestation. levothyroxine-treated pregnant patients need close monitoring with serum thyroid stimulating hormone (TSH) to avoid or- or under treatment. There is no consensus about whether to initiate levothyroxine in women with mild forms of gestational thyroid hypofunction. However, in light of current evidence it is reasonable to treat subclinically hypothyroid women with levothyroxine, particularly if the TSH is >10 mIU/L or the thyroperoxidase antibody is positive. Women who are not treated need to be followed to ensure that treatment is initiated promptly if thyroid failure progresses. Additional studies are needed to better understand the effects of the initiation of levothyroxine in early gestation in subclinically hypothyroid and hypothyroxinemic women and to determine optimal strategies for thyroid function screening in preconception and pregnancy.

CONCLUSION

The diagnosis and management of hypothyroidism in the peripregnancy period present specific challenges. In making management decisions, it is essential to weigh the risks and benefits of treatments not just for the mother but also for the fetus.

Antepartum Care for Pregnant People with Overt Hypothyroidism, Subclinical Hypothyroidism, and Positive Thyroid Autoantibodies

Maternal thyroid hormones are critical for the growth and development of a healthy fetus. During pregnancy, maternal thyroid hormone production is increased to meet the demands of fetal growth. The purpose of this review is to provide clinicians with current evidence about possible adverse maternal and fetal effects of hypothyroidism in pregnancy, including the role of hypothyroidism in recurrent pregnancy loss. In addition, clinical presentation, evidence-based screening guidelines, and evidence-based treatments are discussed.

Subclinical hypothyroidism in women's health: from pre- to post-menopause

OBJECTIVE

Subclinical hypothyroidism (SCH) is a quite frequent condition among women, affecting 3-12% of the general population. Its consequences on women's health in reproductive age, pregnancy and menopause have been extensively investigated but data about the effective impact of treatment with levothyroxine (LT4) remain conflicting.

METHODS

This is a narrative review and analysis of the most relevant data until June 2021.

RESULTS

SCH may affect reproduction. Evidence suggests that women with SCH undergoing assisted reproductive technique (ART) may benefit from LT4 therapy whereas there are no conclusive data regarding women attempting natural conception. SCH may be associated with several negative pregnancy outcomes, that is to say recurrent pregnancy loss (RPL), preterm delivery, preeclampsia and neurocognitive disturbances of offspring. However, the protective role of LT4 treatment has been established in selected cases, for instance in thyroid peroxidase antibody (TPOAb) -positive women with TSH greater than the pregnancy specific reference range and/or in TPOAb-negative women with TSH >10.0 mIU/L. In menopause, SCH can worsen the negative cardio-metabolic effects of hormonal loss and/or aging, by exacerbating dyslipidaemia and hypertension. Nevertheless, robust data about the benefits of LT4 therapy are still lacking and treatment should be encouraged with caution.

CONCLUSIONS

SCH represents a challenging condition during pre- and post- menopause. An aware knowledge of its possible principal consequences could help all clinicians who are involved in women's health to manage more properly it, preventing its sequelae.

Impact of Thyroid Function on Pregnancy and Neonatal Outcome in Women with and without PCOS

Background: Women with polycystic ovary syndrome (PCOS) are more prone to autoimmune thyroiditis, and both disorders lead to subfertility and pregnancy-related complications. The aim of this study was to investigate whether mothers with and without PCOS and their offspring have comparable thyroid parameters at term and how thyroid parameters are associated with perinatal outcome in this population. Methods: This cross-sectional observational study was performed in a single academic tertiary hospital in Austria. Seventy-nine pregnant women with PCOS and 354 pregnant women without PCOS were included. Blood samples were taken from the mother and cord blood at birth. Primary outcome parameters were maternal and neonatal thyroid parameters at delivery. Secondary outcome parameters were the composite complication rate per woman and per neonate. Results: Thyroid dysfunction was more prevalent among PCOS women (p < 0.001). At time of birth, free triiodothyronine (fT3) levels were significantly lower in PCOS than in non-PCOS women (p = 0.005). PCOS women and their neonates had significantly higher thyreoperoxidase antibody (TPO-AB) levels (p = 0.001). Women with elevated TPO-AB had a significantly higher prevalence of hypothyroidism (p < 0.001). There was a significant positive correlation between maternal and neonatal free thyroxine, fT3 and TPO-AB levels. There were no significant differences in thyroid parameters between women or neonates with or without complications. Conclusions: Our results demonstrate a higher prevalence of thyroid dysfunction and autoimmunity in PCOS women, supporting a common etiology of both disorders. We were not able to show an association between complication rate and thyroid parameters.

Assessment and treatment of thyroid disorders in pregnancy and the postpartum period

Thyroid disorders are prevalent in pregnant women. Furthermore, thyroid hormone has a critical role in fetal development and thyroid dysfunction can adversely affect obstetric outcomes. Thus, the appropriate management of hyperthyroidism, most commonly caused by Graves disease, and hypothyroidism, which in iodine sufficient regions is most commonly caused by Hashimoto thyroiditis, in pregnancy is important for the health of both pregnant women and their offspring. Gestational transient thyrotoxicosis can also occur during pregnancy and should be differentiated from Graves disease. Effects of thyroid autoimmunity and subclinical hypothyroidism in pregnancy remain controversial. Iodine deficiency is the leading cause of hypothyroidism worldwide. Despite global efforts to eradicate iodine deficiency disorders, pregnant women remain at risk of iodine deficiency due to increased iodine requirements during gestation. The incidence of thyroid cancer is increasing worldwide, including in young adults. As such, the diagnosis of thyroid nodules or thyroid cancer during pregnancy is becoming more frequent. The evaluation and management of thyroid nodules and thyroid cancer in pregnancy pose a particular challenge. Postpartum thyroiditis can occur up to 1 year after delivery and must be differentiated from other forms of thyroid dysfunction, as treatment differs. This Review provides current evidence and recommendations for the evaluation and management of thyroid disorders in pregnancy and in the postpartum period.

Oxidative stress and DNA damage status in couples undergoing in vitro fertilization treatment

This study examined the status of oxidative stress in 599 couples undertaking in vitro fertilization (IVF) treatment and its association with reproductive hormones, smoking, and outcomes. Oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide (H₂O₂), catalase (CAT), and total antioxidant capacity (TAC) were determined in follicular fluid and seminal plasma. Tail moment (TM) was used to evaluate DNA damage in the sperm and granulosa cells. Reproductive hormones in serum and cotinine (COT) in urine, follicular fluid, and seminal plasma samples were determined. Separate multivariate linear regression was used to assess associations between levels of each oxidative stress biomarker and each hormone and smoking parameter (modeled as natural log-transformed). The findings indicate that some oxidative stress and DNA damage biomarkers played a role in disrupting certain reproductive hormones in women and their male partners either by overproducing reactive oxygen species or reducing antioxidant defense capacity. Although women were nonsmokers, COT levels > 50 and 10 µg/L in urine and follicular were observed in 5.7 and 1.7%, respectively. Levels of follicular fluid COT were positively associated with H₂O₂ and TM. We used log-binomial multivariate regression to estimate relative risks for the association between oxidative stress/DNA damage and IVF binary outcomes (fertilization rate > 50%, biochemical pregnancy, clinical pregnancy, and live birth). An increase in the CAT levels of follicular fluid was associated with a 48 and 41% decrease in the risk of poor fertilization rate (≤50%) and unsuccessful live birth, respectively. After the models were adjusted for hormonal factors, the associations remained the same, except that the elevated TAC in follicular fluid became significantly associated with a decrease of 42% in the risk of poor fertilization rate (≤50%). The higher antioxidant activity (CAT and TAC) in follicular fluid might positively impact specific IVF outcomes.

Thyroid Dysfunction after Gonadotropin-Releasing Hormone Agonist Administration in Women with Thyroid Autoimmunity

GnRH agonists (GnRHa) are a useful tool for pretreatment before artificial endometrial preparation for frozen-thawed embryo-transfer (FET). Their prolonged administration has been associated with thyroid dysfunction, both hyper and hypothyroidism. The aim of this study is to investigate the impact of GnRHa administration on thyroid function in women undergoing artificial endometrial preparation. Seventy-eight euthyroid women undergoing endometrial preparation with hormone replacement for FET were retrospectively reviewed. They were divided into two groups according to pretreatment with GnRHa (group A, 42 women) or with an oral contraceptive (group B, 36 women). Group A was subsequently divided into two subgroups according to thyroid autoimmunity presence. Thyroid function has been evaluated and compared among groups and subgroups. Our results did not show any statistically significant differences in age, body mass index, and basal thyroid stimulating hormone (TSH). Total estradiol dosage, duration of treatment, and endometrial thickness were comparable among groups. When TSH was measured 14 days after embryo transfer, no significant differences between the two groups were reported. Among women of group A, TSH was significantly higher only in women with thyroid autoimmunity. GnRHa seems to be associated with thyroid dysfunction in women with thyroid autoimmunity undergoing hormone replacement therapy for FET.

Thyroid autoimmunity and reproduction: Bidirectional relationship that continues to intrigue

Today, infertility is not only a serious health but also a psycho-social problem, one that is on the rise in the world. Thyroid autoimmunity (TAI) is the most common disease of the thyroid gland in the reproductive period, which can affect spontaneous conception as well as conception through assisted reproduction technology (ART), but also the maintenance of healthy pregnancy. It can also cause numerous maternal and fetal complications. There is a wide array of publications on the topic of the mechanisms of association between TAI and reproduction, with the question of whether thyroid autoantibodies are solely tissue-specific antibodies, whether and when to start levothyroxine treatment, and that we require more fundamental research on the direct effect of thyroid autoantibodies starting from folliculogenesis to embryogenesis and implantation as well as the post-implantation embryo development, but also the composition of the follicular fluid as a microenvironment of enormous importance for the maturation of the oocytes which thyroid autoantibodies reach via the blood-follicle barrier.

Effect of thyroid function on assisted reproduction outcomes in euthyroid infertile women: A single center retrospective data analysis and a systematic review and meta-analysis

BACKGROUND

The influence of thyroid-stimulating hormone (TSH) on gestational outcomes have been studied and checked whether differing TSH levels are relevant on human reproduction outcomes. International guidelines recommend TSH values <2.5 mIU/L in women trying to conceive, since values above this level are related to a higher frequency of adverse reproductive outcomes. This study aimed to evaluate whether TSH values correlate with different gestational outcomes in euthyroid infertile women without autoimmune thyroid disease.

METHODS

A retrospective cohort study was conducted involving 256 women who underwent in vitro fertilization (IVF) treatment. The participants were divided into two groups: TSH 0.5-2.49 mIU/L (n=211) and TSH 2.5-4.5 mIU/L (n=45). The clinical data, hormonal profiles and reproductive outcomes were compared between groups. Additionally, a systematic review with meta-analysis following the PRISMA protocol was carried out in PubMed/MEDLINE, EMBASE, and SciELO, with no time or language restrictions, for articles comparing TSH groups named "low TSH" (<2,5 mIU/L) and "high TSH" (≥2.5 mIU/L). A meta-analysis of proportions was performed with pooled estimates expressed as relative risk (RR) of events and a random effects model.

RESULTS

Age, BMI, free thyroxine levels (FT4) hormonal profile and IVF outcomes were not different between groups, neither gestational outcomes (p=0.982). Also, no difference was observed when the TSH and FT4 levels were compared between patients with positive or negative gestational outcomes (p=0.27 and p=0.376). Regarding the systematic review with meta-analysis, 17 studies from 2006 to 2022 were included, and added by this original retrospective research comprising 13.247 women undergoing IVF. When comparing the proportions of clinical pregnancy between the TSH groups, no significant difference was found (RR 0.93, 95% CI 0.80-1.08), with high between studies heterogeneity (I²: 87%; τ²: 0.0544; p<0.01). The number of deliveries was not significantly different between groups, despite a trend towards higher frequency in the high-TSH group (RR 0.96, 95% CI 0.90-1.02).

CONCLUSION

Variation in TSH levels within the normal range was not associated with pregnancy and delivery rates in women, without autoimmune thyroid disease, who underwent IVF treatment.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD 42022306967.

Thyroid autoimmunity and its negative impact on female fertility and maternal pregnancy outcomes

Thyroid autoimmunity (TAI) is commonly defined as the presence of thyroperoxidase antibodies (TPOAbs) and/or thyroglobulin antibodies (TgAbs), which predisposes an individual to hypothyroidism. TAI affects nearly 10% of women of reproductive age and evokes great interest from clinicians because of its potentially negative impact on female fertility and pregnancy course. In this mini-review, we review the current literature concerning the influence of TPOAb or TPOAb/TgAb positivity without thyroid dysfunction on reproduction. TAI may negatively affect female fertility; several studies have found an increased prevalence of TAI in infertile women, especially in those with unexplained infertility and polycystic ovary syndrome. According to some observations, TAI might also be connected with premature ovarian insufficiency and endometriosis. The relationship between TAI and an increased risk of pregnancy loss is well documented. The pathophysiological background of these observations remains unclear, and researchers hypothesize on the direct infiltration of reproductive organs by thyroid antibodies, co-existence of TAI with other autoimmune diseases (either organ specific or systemic), immunological dysfunction leading to inhibition of immune tolerance, and relative thyroid hormone deficiency. Interestingly, in the current literature, better outcomes of assisted reproductive technology in women with TAI have been reported compared with those reported in earlier publications. One plausible explanation is the more widespread use of the intracytoplasmic sperm injection method. The results of randomized clinical trials have shown that levothyroxine supplementation is ineffective in preventing adverse pregnancy outcomes in women with TAI, and future research should probably be directed toward immunotherapy.

Impact of maternal nutrition during early pregnancy and diet during lactation on lactoferrin in mature breast milk

OBJECTIVE

Lactoferrin supplementation is a promising strategy to prevent infections in neonates. Exploring whether maternal nutritional status in early pregnancy and maternal diet during lactation are associated with lactoferrin concentrations in mature human milk can provide early warning and allow timely adjustment.

METHODS

In this follow-up cohort study, 206 participants were recruited at Peking University People's Hospital from June 2018 to June 2019. The levels of albumin and thyroid-stimulating hormones (TSH) were determined as nutritional indicators during early pregnancy. Information on maternal diet during lactation was collected with a semiquantitative food frequency questionnaire, and the lactoferrin concentrations in breast milk were examined at around 42 d postpartum.

RESULTS

The median level (interquartile range) of lactoferrin in breast milk was 2844.2 (2568.1, 3103.1) μg/mL. Overall, 5.5% of participants had lower albumin (<40 g/L), and 21.6% had elevated TSH (>2.5 mIU/L), respectively. The concentration of lactoferrin was higher (216.8 [13.4, 420.2] μg/mL) in women with lower albumin levels than in those with normal levels, and elevated TSH had no effect. A 1 g increase in egg intake led to a 0.3 (0.0, 0.6) μg/mL increase in lactoferrin concentration. Lactoferrin levels were also affected by intake of energy, protein, cholesterol, and vitamin A.

CONCLUSIONS

Women with lower albumin levels in early pregnancy had higher levels of lactoferrin in mature breast milk. TSH was not related to lactoferrin levels. Intake of energy, protein, cholesterol, and vitamin A may have contributed to lactoferrin concentrations in milk, and egg intake was positively associated with lactoferrin.

More Live Births in Primary Subfertile Intracytoplasmic Sperm Injection-Treated Women with High Normal TSH Levels

OBJECTIVES

The aim of this study was to analyze the fertility outcome in intracytoplasmic sperm injection (ICSI)-treated women across normal range thyroid-stimulating hormone (TSH) levels. Published results are inconclusive about optimal TSH levels and fertility.

DESIGN

This is a retrospective cohort study in 752 ICSI-treated women with predominantly severe male factor subfertility, starting treatment between the first of January 2008 and the first of March 2012 with a follow-up until 2014. Participants/Materials, Setting, Methods: Women aged 22-45 years with TSH 0.3-4.5 mIU/L without thyroid hormone substitution were included in Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands, an iodine-sufficient area. Demographic and baseline characteristics were compared between groups of patients based on TSH, using one-way ANOVA, Kruskal-Wallis ANOVA, and χ2 test. The patient was the unit of analysis: all cumulative cycles per patient were analyzed up to and including the first ongoing pregnancy. The primary outcome was a cumulative live birth rate. Clinical pregnancy rate, pregnancy loss, and ongoing pregnancy rate were secondary outcomes. The χ2 test and logistic regression were used to compare interquartile groups while adjusting for confounders. Logistic regression was used with the natural logarithm of TSH as a continuous predictor. Primary and secondary subfertile women were analyzed separately.

RESULTS

Analysis of the total cohort (n = 752) showed no difference in fertility outcomes across the normal TSH range. The cumulative live birth rate for the 4 groups of primary subfertile women (n = 455) was 76% in the upper TSH quartile compared to 56%, 60%, and 59% in the lower TSH quartiles.

LIMITATIONS

Levels of thyroxine and presence of thyroid autoimmunity were not measured in this retrospective cohort study.

CONCLUSIONS

The observation that a higher live birth rate was found in primary subfertile ICSI-treated women with high but allegedly normal TSH levels contributes to the hypothesis that in certain subfertile women in addition to a male factor, female factors such as subtle hypothyroidism and/or thyroid autoimmunity may play a role in keeping them from conception, which can be overcome by the process of ICSI.

Analysis of basal serum TSH, FT3, and FT4 levels based on age, sampling time in women with infertility

Background

To analyze the characteristics of basal thyroid hormone levels in infertile women consulting for assisted reproductive technology (ART) treatment.

Methods

This was a retrospective study. Serum TSH, FT3 and FT4 levels of women seeking ART consultation were tested routinely. Analyses were performed based on age and sampling time. One-way ANOVA or Kruskal-Wallis rank sum test was used to compare the continuous data among the groups, and the chi-square test or Fisher’s exact test was used to compare categorical data where appropriate.

Results

A total of 6426 women were initially included in the study. After exclusion criteria were applied, the remaining 4126 women were categorized into different groups. The prevalence of subclinical hypothyroidism significantly decreased with age and sampling time, from 21.09 to 11.91% and from 28.57 to 10.67%, respectively (P < 0.001, respectively). Mean serum TSH, FT3, and FT4 levels decreased significantly with age (P = 0.017, < 0.001, < 0.001, respectively). In the context of sampling time, TSH levels from early in the morning were significantly higher (P < 0.001), while FT4 and FT3 levels were similar in different groups (P = 0.258, 0.300, respectively).

Conclusions

The prevalence of subclinical hypothyroidism significantly decreased with increasing age and sampling time, as did the serum TSH levels. Even though, the establishment of reference interval of TSH level based on age or sampling time was not recommended. Full consideration of age and sampling time should be carefully taken before initiation of treatment.

Development and validation of a risk prediction index for severe maternal morbidity based on preconception comorbidities among infertile patients

OBJECTIVE

To develop and validate a preconception risk prediction index for severe maternal morbidity (SMM), defined by the Centers for Disease Control and Prevention as indicators of a life-threatening complication, among infertile patients.

DESIGN

Retrospective analysis of live births and stillbirths from 2007 to 2017 among infertile women.

SETTING

National commercial claims database.

PATIENT(S)

Infertile women identified on the basis of diagnosis, testing, or treatment codes.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcome was SMM, identified as any indicator from the Centers for Disease Control and Prevention Index except blood transfusion alone, which was found to overestimate cases. Twenty preconception comorbidities associated with a risk of SMM were selected from prior literature. Targeted ensemble learning methods were used to rank the importance of comorbidities as potential risk factors for SMM. The independent strength of the association between each comorbidity and SMM was then used to define each comorbidity's risk score.

RESULT(S)

Among 94,097 infertile women with a delivery, 2.3% (n = 2,181) experienced an SMM event. The highest risk of SMM was conferred by pulmonary hypertension, hematologic disorders, renal disease, and cardiac disease. Associated significant risks were lowest for substance abuse disorders, prior cesarean section, age ≥40 years, gastrointestinal disease, anemia, mental health disorders, and asthma. The receiver operating characteristic area under the curve for the developed comorbidity score was 0.66. Calibration plots showed good concordance between the predicted and actual risk of SMM.

CONCLUSION(S)

We developed and validated an index to predict the probability of SMM on the basis of preconception comorbidities in patients with infertility. This tool may inform preconception counseling of infertile women and support maternal health research initiatives.

The Impact of High-Normal TSH Levels on Reproductive Outcomes in Women Undergoing ART Treatment: a Systematic Review and Meta-analysis

The role of high-normal thyroid-stimulating hormone levels has been of great concern recently. However, the conclusions of different studies are inconsistent. To assess whether high-normal conditions have an impact on reproductive and obstetric outcomes in euthyroid women undergoing ART treatment, a systematic review and meta-analysis was performed. Eligible studies published up to December 30, 2020, were searched from the PubMed, EMBASE, COCHRANE, and CNKI databases. Quality assessment of the included studies, data extraction, and synthesis were performed separately. RevMan 5.2 was used to carry out the meta-analysis. A total of 23 studies that included 25,143 patients were included. We observed similar clinical pregnancy rates (RR = 1.01, 95% CI: 0.99-1.05), miscarriage rates (RR = 0.95, 95% CI: 0.84-1.08), live birth rates (RR = 1.04, 95% CI: 0.99-1.09), birth weights (SMD = 0.07, 95% CI: -0.02 to 0.16), and gestational ages (SMD = 0.07, 95% CI: -0.02 to 0.16) between the high-normal TSH group and low TSH group. Subgroup analysis showed similar results. High-normal TSH levels were associated with similar clinical pregnancy rates, live birth rates, and miscarriage rates to those of women with low TSH levels. The results suggested that preconceptional TSH levels, regardless of potentially being affected by the controlled ovarian stimulation process, had little impact on reproductive and obstetric outcomes and should not be of great concern.

Changes in thyroid function during controlled ovarian hyperstimulation (COH) and its impact on assisted reproduction technology (ART) outcomes: a systematic review and meta-analysis

BACKGROUND

To investigate the thyroid function changes during controlled ovarian hyperstimulation (COH) and ascertain its impact on reproductive outcomes.

METHODS

We conducted meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed to identify studies reported changes in thyroid parameters during COH. We analyzed thyroid-stimulating hormone (TSH) levels, free thyroxin (fT4) levels, changes in estrogens (E2), thyroxine-binding globulin (TBG), relative risks (RRs) of clinical pregnancy rate (CPR), live birth rate (LBR), and mean difference (MD) of TSH increment between the miscarriage group and ongoing pregnancy group.

RESULTS

This meta-analysis included fifteen individual studies (n = 1665 subjects). At the end of COH, the mean TSH (2.53 mIU/L; 95% CI, 2.19 to 2.88; I² = 92.9%) exceeded the upper limit (2.5 mIU/L) and remained above the threshold until one month following embryo transfer (ET). Thyroxin decreased from baseline to the end of COH (-0.18 ng/l; 95% CI, -0.35 to 0.00; I² = 92.2%). The CPR and LBR of patients with TSH exceeding the cutoff after COH were significantly lower than those of patients with TSH below the threshold (CPR: RR, 0.62; 95% CI, 0.47 to 0.82; I² = 0.0% and LBR: RR, 0.64; 95% CI, 0.44 to 0.92; I² = 0.0%). The MD of the increment in TSH levels between the miscarriage and ongoing pregnancy groups was 0.40 mIU/L (95% CI, 0.15 to 0.65; I² = 0.0%).

CONCLUSIONS

This meta-analysis shows that TSH increases and fT4 decreases during COH. COH-induced thyroid disorder impairs reproductive outcomes.

Impact of preconceptional serum thyroid stimulating hormone values ranging between 2.5 and 4.5 mIU/L on live birth rates following ovulation induction and intrauterine insemination treatment for unexplained infertility

BACKGROUND

Contrary to overt hypothyroidism, the true impact of subclinical hypothyroidism on fertility has not been well established. This study aimed to investigate whether serum thyroid stimulating hormone (TSH) values between 2.5 and 4.5 mIU/L are associated with lower pregnancy rates compared to TSH levels between 0.3 and 2.5 mIU/L in women undergoing ovulation induction with gonadotropins and intrauterine insemination (IUI) for unexplained infertility.

METHODS

Medical records of couples with unexplained infertility who underwent IUI treatment between January 2013 and December 2018 were reviewed retrospectively. Cycle characteristics and pregnancy outcomes of patients with serum TSH levels between 0.3-2.5 mIU/L and 2.5-4.5 mIU/L were compared. Primary outcome measures were clinical pregnancy and live birth rate. Secondary outcome measures were total dose of gonadotropin administration, duration of ovulation induction and miscarriage rate.

RESULTS

A total of 726 euthyroid women who underwent 1465 cycles of ovulation induction with gonadotropins and IUI were included in the analyses. Patient and cycle characteristics of the two study groups were similar. No statistically significant differences could be detected in the clinical pregnancy (p = 0.74) and live birth rates (p = 0.38) between the two groups. Duration of ovulation induction, total gonadotropin dosage, number of follicles > 17 mm on the trigger day and the miscarriage rates were similar in the two groups.

CONCLUSION

In euthyroid women undergoing ovulation induction with gonadotropins and IUI for unexplained infertility, the range of preconceptional serum TSH values between 2.5 and 4.5 mIU/L is not associated with lower pregnancy rates when compared to TSH levels between 0.3 and 2.5 mIU/L.

Thyroid-stimulating hormone level is negatively associated with fertilization rate in patients with polycystic ovary syndrome undergoing in vitro fertilization

OBJECTIVE

In this study, we investigated the effect of thyroid-stimulating hormone (TSH) level on the outcomes of in vitro fertilization (IVF) in patients with polycystic ovary syndrome (PCOS).

METHODS

Data pertaining to 60 patients who underwent IVF between May 2017 and May 2018 were included in the study. Thirty-two patients were diagnosed as PCOS (PCOS group) and 28 patients had tubal infertility (control group). Serum and follicular fluid TSH levels and follicular cyclic AMP (cAMP) level were detected by ELISA. TSH receptor (TSHR) expression level in granulosa cells was quantified by RT-PCR and Western blot.

RESULTS

In the PCOS group, oocyte maturation rate and fertilization rate were significantly lower than in the control group. Serum and follicular fluid TSH levels and ovarian cAMP level were higher in the PCOS group with an upregulation of ovarian TSHR. On multivariate linear regression analysis, fertilization rate showed a negative correlation with TSH levels in serum (B = -0.106, P = 0.005) and follicular fluid (B = -0.107, P = 0.001).

CONCLUSION

In PCOS patients, TSH levels, both in serum and follicular fluid, were negatively correlated with IVF oocyte maturation rate and fertilization rate. The effect of TSH on controlled ovarian hyperstimulated oocyte growth was likely mediated by the TSHR/cAMP signaling pathway.

Thyroid function modifications in women undergoing controlled ovarian hyperstimulation for in vitro fertilization: a systematic review and meta-analysis

OBJECTIVE

To investigate the impact of controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF) on thyroid function.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertile women undergoing conventional IVF or intracytoplasmic sperm injection.

INTERVENTION(S)

Systematic search of PubMed, MEDLINE, Embase, Scopus, and Web of Science from inception until November 2020. Studies could be included only if they met the following criteria: subjects were classified as euthyroid or hypothyroid; serum thyroid-stimulating hormone (TSH) and/or free thyroxine (FT4) levels were evaluated before COH; and the same thyroid function test was reassessed after COH (i.e., at the time of trigger for final follicle maturation and/or at pregnancy test).

MAIN OUTCOME MEASURE(S)

Mean difference (MD) between the serum TSH or FT4 levels assessed after COH and before COH.

RESULT(S)

In euthyroid women, the serum TSH levels assessed at the time of trigger and at the time of pregnancy test were significantly higher than those at baseline (MD: 0.69 mIU/L, 95% confidence interval [CI]: 0.30-1.08, I² = 93% and MD: 0.67, 95% CI: 0.49-0.85, I² = 72%, respectively). The serum FT4 levels did not undergo significant changes. Subanalysis confirmed an increase in the TSH level after restricting the analysis to women treated with gonadotropin-releasing hormone agonist protocols and to those who achieved pregnancy. A pronounced increase in the TSH level was observed in women treated for hypothyroidism (MD: 1.50 mIU/L, 95% CI: 1.10-1.89, I² = 0%).

CONCLUSION(S)

Pooling of the results showed a significant increase in serum TSH level in women undergoing COH for IVF. This change was particularly pronounced in women treated for hypothyroidism. New thyroid function screening strategies for women undergoing COH are warranted.

Effect of the Cut-Off Level for Thyroid-Stimulating Hormone on the Prevalence of Subclinical Hypothyroidism among Infertile Mexican Women

The primary aim of this study was to compare the prevalence of subclinical hypothyroidism (SCH) using two different cut-off levels for TSH values (≥2.5 mIU/L versus ≥4.1 mIU/L). The secondary objective was to analyze the clinical-biochemical characteristics in women with and without SCH. This was a retrospective cross-sectional study. In total, 1496 Mexican women with infertility were included: Group 1, women with TSH levels ranging between 0.3 and 2.49 mIU/L, n = 886; Group 2, women with TSH between 2.5 and 4.09 mIU/L, n = 390; and Group 3, women with TSH ≥4.1 mIU/L n = 220. SCH prevalence was 40.7% (CI 95%: 38.3-43.3%) with TSH cut-off ≥ 2.5 mIU/L, and 14.7% (CI 95%: 12.7-16.5%) with TSH cut-off ≥ 4.1 mIU/L, (p = 0.0001). The prevalence of overweight was higher in Group 2 than in Groups 1 and 3. Thyroid autoimmunity, obesity and insulin resistance were higher in Group 3 than in Group 1 (p < 0.05). No other differences were observed between groups. Conclusions: The prevalence of SCH in our selected patients increased almost three times using a TSH cut-off ≥ 2.5 mIU/L compared with a TSH cut-off ≥ 4.1 mIU/L. Women with TSH ≥4.1 mIU/L compared with TSH cut-off ≤ 2.5 mIU/L more often presented with obesity, thyroid autoimmunity and insulin resistance.

Clinical practice guidelines for recurrent miscarriage in high-income countries: a systematic review

Recurrent miscarriage affects 1-2% of women of reproductive age, depending on the definition used. A systematic review was conducted to identify, appraise and describe clinical practice guidelines (CPG) published since 2000 for the investigation, management, and/or follow-up of recurrent miscarriage within high-income countries. Six major databases, eight guideline repositories and the websites of 11 professional organizations were searched to identify potentially eligible studies. The quality of eligible CPG was assessed using the Appraisal of Guidelines for Research and Evaluation (AGREE II) Tool. A narrative synthesis was conducted to describe, compare and contrast the CPG and recommendations therein. Thirty-two CPG were included, from which 373 recommendations concerning first-trimester recurrent miscarriage were identified across four sub-categories: structure of care (42 recommendations, nine CPG), investigations (134 recommendations, 23 CPG), treatment (153 recommendations, 24 CPG), and counselling and supportive care (46 recommendations, nine CPG). Most CPG scored 'poor' on applicability (84%) and editorial independence (69%); and to a lesser extent stakeholder involvement (38%) and rigour of development (31%). Varying levels of consensus were found across CPG, with some conflicting recommendations. Greater efforts are required to improve the quality of evidence underpinning CPG, the rigour of their development and the inclusion of multi-disciplinary perspectives, including those with lived experience of recurrent miscarriage.

2021 European Thyroid Association Guideline on Thyroid Disorders prior to and during Assisted Reproduction

Severe thyroid dysfunction may lead to menstrual disorders and subfertility. Fertility problems may persist even after restoring normal thyroid function, and then an assisted reproductive technology (ART) may be a solution. Prior to an ART treatment, ovarian stimulation is performed, leading to high oestradiol levels, which may lead to hypothyroidism in women with thyroid autoimmunity (TAI), necessitating levothyroxine (LT4) supplements before pregnancy. Moreover, women with the polycystic ovarian syndrome and idiopathic subfertility have a higher prevalence of TAI. Women with hypothyroidism treated with LT4 prior to ART should have a serum TSH level <2.5 mIU/L. Subfertile women with hyperthyroidism planning an ART procedure should be informed of the increased risk of maternal and foetal complications, and euthyroidism should be restored and maintained for several months prior to an ART treatment. Fertilisation rates and embryo quality may be impaired in women with TSH >4.0 mIU/L and improved with LT4 therapy. In meta-analyses that mainly included women with TSH levels >4.0 mIU/L, LT4 treatment increased live birth rates, but that was not the case in 2 recent interventional studies in euthyroid women with TAI. The importance of the increased use of intracytoplasmic sperm injection as a type of ART on pregnancy outcomes in women with TAI deserves more investigation. For all of the above reasons, women of subfertile couples should be screened routinely for the presence of thyroid disorders.

Thyroid function testing and management during and after pregnancy among women without thyroid disease before pregnancy

BACKGROUND

Screening in pregnancy for subclinical hypothyroidism, often defined as thyroid-stimulating hormone (TSH) greater than 2.5 mIU/L or greater than 4.0 mIU/L, is controversial. We determined the frequency and distribution of TSH testing by gestational age, as well as TSH values associated with treatment during pregnancy and the frequency of postpartum continuation of thyroid hormone therapy.

METHODS

We performed a retrospective cohort study of pregnancies in Alberta, Canada. We included women without thyroid disease who delivered between October 2014 and September 2017. We used delivery records, physician billings, and pharmacy and laboratory administrative data. Our key outcomes were characteristics of TSH testing and the initiation and continuation of thyroid hormone therapy. We calculated the proportion of pregnancies with thyroid testing and the frequency of each specific thyroid test.

RESULTS

Of the 188 490 pregnancies included, 111 522 (59.2%) had at least 1 TSH measurement. The most common time for testing was at gestational week 5 to 6. Thyroid hormone therapy was initiated at a median gestational age of 7 (interquartile range 5-12) weeks. Among women with first TSH measurements of 4.01 to 9.99 mIU/L who were not immediately treated, the repeat TSH measurement was 4.00 mIU/L or below in 67.9% of pregnancies. Thyroid hormone was continued post partum for 44.6% of the women who started therapy during their pregnancy.

INTERPRETATION

The findings of our study suggest that current practice patterns may contribute to overdiagnosis of hypothyroidism and overtreatment during pregnancy and post partum.

Association between thyroid function and risk of gestational diabetes mellitus in assisted pregnancies: A retrospective cohort study

AIMS

To explore the association between thyroid function and gestational diabetes mellitus (GDM) risk in assisted pregnancies.

METHODS

We screened 57,386 pregnant women treated from February 2013 to October 2017, and 2211 patients were retrospectively enrolled, and their data were analyzed based on quintile groups constituted based on serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), and thyroid peroxidase antibody (TPOAb) levels. Odds ratios (ORs) of GDM were analyzed by multivariate logistic regression, adjusted for maternal age and pre-pregnancy body mass index (BMI).

RESULTS

The prevalence rate of GDM was 20.1%. Lower FT4 levels were associated with an increased risk of GDM (OR_Q2 = 1.512, 95% confidence interval [CI] 1.073-2.132, p = 0.018; OR_Q1 = 1.620, 95% CI 1.161-2.261, p = 0.005), but this association disappeared after adjustments. TPOAb+ titer was associated with an increased risk of GDM (aOR = 1.472, 95% CI 1.068-2.028, p = 0.018). Higher TSH (aOR_Q5 = 2.882, 95% CI 1.919-6.975, p = 0.019) or lower FT4 (aOR_Q1 = 3.156, 95% CI 1.088-9.115, p = 0.034) levels were associated with an increased risk of GDM in assisted pregnancies for TPOAb+ patients.

CONCLUSION

TPOAb+ is an independent risk factor for GDM in patients with assisted pregnancies. Higher TSH or lower FT4 levels, with TPOAb+ detection, are risk factors for GDM in assisted pregnancies.

Reproductive Outcomes in Cases of Subclinical Hypothyroidism and Thyroid Autoimmunity: A Narrative Review

Thyroid diseases are relatively common in women in the reproductive period. It is currently understood that clinically-evident thyroid disorders may impair ovulation and, consequently, fertility. However, to date it has not been proven that high serum levels of thyroid-stimulating hormone and/or positivity for antithyroid antibodies are associated to a reduction in fertility, mainly in the absence of altered thyroxine levels. The present comprehensive review aims to present current data on the association between subclinical hypothyroidism and/or thyroid autoimmunity and reproductive outcomes.

[Diagnostic and treatment of subclinical hypothyroidism in pregnant and planning pregnancy patients: modern view of the problem]

There is no universal diagnostic and treatment strategy of subclinical hypothyroidism (SHT) in pregnant women and those who are planning pregnancy due to differences in population-specific and trimester-specific thyroid-stimulating hormone (TSH) reference values, influence of thyroid autoimmunity markers on pregnancy outcomes, adherence to fixed universal cutoff concentrations TSH in Russia and multidisciplinary team care with different treatment opinions involving. An absence of universal approach to SHT leads to excess treatment, financial and psychological burden on pregnant women.Up to American Thyroid Association (ATA) Guidelines 2017 and project of Clinical Guidelines of Russian Association of Endocrinologists 2019 a treatment strategy of SHT should be left up to the endocrinologist to choose. In our paper we systematize global scientific and clinical experience of planning and management pregnancies with SHT to help physicians to choose treatment option based on principals of evidence-based medicine.