Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline

Antenatal screening for thyroid dysfunction: pre-term birth, low birth-weight, and growth restriction

OBJECTIVE

To assess pre-term birth, low birth-weight and growth restriction according to maternal thyroid screening results and subsequent treatment.

METHODS

This is a nonintervention nested case-control study derived from 10,052 asymptomatic women previously screened during the first trimester marker with anti-thyroid peroxidase antibodies, serum thyroid stimulating hormone, and free thyroxine. Screening results had been classified as positive with one or more markers outside the normal range and referred to an endocrinologist. Cases were 512 women with positive results and information on recommended treatment: 204 thyroxine, propylthiouracil or surgery, and 308 no treatment or only iodine. Controls were a sequential sample of 1292 women with negative results. All cases and controls had information on gestation at delivery or birth-weight. Outcome measures were pre-term birth (<37 weeks), low birth-weight (<2.5 kg) and, for singletons, small for gestational age (SGA; <10th percentile).

RESULTS

Among singleton pregnancies, there was a higher prevalence of both pre-term birth (risk ratio (RR) 1.69, 95% confidence interval (CI) 1.21-2.36, p < .002) and low birth-weight (RR 1.72, 95% CI 1.13-2.62, p < .02) in cases compared with controls. An increase in low birth-weight was also present in term pregnancies, but not significant (RR 1.80, 95% CI 0.78-4.14, p = .16), and there was no difference in SGA prevalence (1.24, 95% CI 0.93-1.65, p = .14). Among cases there was no significant difference in these rates according to treatment even after logistic regression, allowing for the individual screening marker levels and maternal weight.

CONCLUSIONS

Women with positive thyroid screening results are at increased risk of pre-term birth regardless of thyroid dysfunction or subsequent treatment. An association with low birth-weight is probably secondary to early delivery.

Evaluation and Management of Thyrotoxicosis During Pregnancy

This review summarizes the diagnosis and management of thyrotoxicosis in pregnancy. The diagnostic clinical and biochemical considerations used to distinguish the various etiologies of hyperthyroidism from appropriate physiologic changes during pregnancy will be outlined. Finally, the review will discuss the risks and benefits of available options for the treatment of thyrotoxicosis during pregnancy, to mitigate the risks of fetal hyperthyroidism.

Sex-specific effect of maternal thyroid peroxidase antibody exposure during pregnancy on 5- to 6-year-old children's cardiometabolic risk score: the Ma'anshan birth cohort study

OBJECTIVE

To explore the association between maternal thyroid peroxidase antibody (TPOAb) exposure and 5- to 6-year-old children's cardiometabolic risk (CMR).

METHODS

A total of 2129 mother-child pairs were recruited from the Ma'anshan Birth Cohort (MABC) study. Serum TPOAb was retrospectively measured in pregnant women using an electrochemiluminescence immunoassay. CMR score was evaluated by the serum glycolipids, blood pressure, and waist circumference for children aged 5-6 years. Growth mixture modelling was used to fit trajectories of TPOAb levels throughout pregnancy. Multiple linear regression models and logistic regression models were used for statistical analyses.

RESULTS

Two thousand one hundred twenty-nine mother-child pairs (mean [SD] age, 26.6 [3.6] years) were enrolled for the final study. Maternal TPOAb exposure in the first trimester increased children's overall CMR, glucose level, HOMA-IR, triglyceride level, boys' overall CMR, boys' glucose level, and girls' glucose level. TPOAb exposure in the first trimester was also associated with lower boys' high-density lipoprotein cholesterol (HDL-C) level. In the second trimester, maternal TPOAb exposure was positively associated with children's triglyceride level. Compared with low TPOAb trajectory, children with high maternal TPOAb trajectory had an increased risk of developing high CMR (OR = 3.40; 95% CI, 1.30-8.90), hyperglycemia (OR = 5.20; 95% CI, 2.20-12.28), insulin-resistance (adjusted OR = 2.12; 95% CI, 1.10-4.07), and hypertriglyceridemia (OR = 2.55; 95% CI, 1.06-6.14).

CONCLUSIONS

The first trimester of pregnancy is a critical period for maternal TPOAb exposure to affect CMR in children, with some sex specificity, mainly to the detriment of boys.

Fetal sexual dimorphism of maternal thyroid function parameters during pregnancy, a single center retrospective real-world study

Introduction

Thyroid function during pregnancy fluctuates with gestational weeks, seasons and other factors. However, it is currently unknown whether there is a fetal sex-specific thyroid function in pregnant women. The purpose of this study was to investigate the fetal sex differences of maternal thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in pregnant women.

Methods

This single-center retrospective real-world study was performed by reviewing the medical records of pregnant women who received regular antenatal health care and delivered liveborn infants in Shanghai First Maternity and Infant Hospital (Pudong branch), from Aug. 18, 2013 to Jul. 18, 2020. Quantile regression was used to evaluate the relationship between various variables and TSH and FT4 concentrations. The quantile regression also evaluated the sex impact of different gestational weeks on the median of TSH and FT4.

Results

A total of 69,243 pregnant women with a mean age of 30.36 years were included. 36197 (52.28%) deliveries were boys. In the three different trimesters, the median levels (interquartile range) of TSH were 1.18 (0.66, 1.82) mIU/L and 1.39 (0.85, 2.05) mIU/L, 1.70 (1.19, 2.40) mIU/L; and the median levels (interquartile range) of FT4 were 16.63 (15.16, 18.31) pmol/L, 14.09 (12.30, 16.20) pmol/L and 13.40 (11.52, 14.71) pmol/L, respectively. The maternal TSH upper limit of reference ranges was decreased more in mothers with female fetuses during gestational weeks 7 to 12, while their FT4 upper limit of the reference ranges was increased more than those with male fetuses. After model adjustment, the median TSH level was 0.11 mIU/L lower (P <0.001), and FT4 level was 0.14 pmol/L higher (P <0.001) for mothers with female fetuses than those with male fetuses during gestational weeks 9 to 12.

Discussion

We identified sexual dimorphism in maternal thyroid function parameters, especially during 9-12 weeks of pregnancy. Based on previous research, we speculated that it may be related to the higher HCG levels of mothers who were pregnant with girls during this period. However, longitudinal studies are needed to determine if fetal sex differences impact the maternal thyroid function across pregnancy.

Neonatal Thyrotoxicosis in Infants of Mothers with Graves' Disease Treated for Radioiodine-Induced Hypothyroidism: A Literature Review

Fetal and neonatal thyrotoxicosis occurs in up to 5% of pregnancies in mothers with Graves' disease (GD). This condition is caused by stimulating antibodies against the thyrotropin receptor (TRAbs) that cross the placenta and may stimulate the fetal thyroid, typically in the second half of pregnancy. GD is often treated with radioiodine, resulting in hypothyroidism in most patients, but TRAbs can persist for several years. Even if a pregnant mother is hypothyroid after radioiodine therapy or surgery, her TRAbs can still, although rarely, induce fetal hyperthyroidism. In this review, we first present two cases of neonatal hyperthyroidism in mothers with GD who became hypothyroid after prior radioiodine therapy, identified through a 10-year analysis of the National Perinatal System in Slovenia. Based on these cases, we provide an overview of existing data on this rare clinical condition in neonates. We also discuss the underlying mechanisms and clinical outcomes based on currently available data. In conclusion, our review highlights the importance of careful monitoring during pregnancy in all women with GD, even in those well managed after radioiodine therapy or surgery.

Evaluation of Anti-Thyroperoxidase (A-TPO) and Anti-Thyroglobulin (A-Tg) Antibodies in Women with Previous Hashimoto's Thyroiditis during and after Pregnancy

Background/Objective: Autoimmune thyroid diseases (AITD) affect 2 to 5% of the general population. This study aimed to determine changes in activity of A-Tg and A-TPO antibodies before, during, and after pregnancy in women with previous AITD. Methods: This was a single-center study with a retrospective review of the medical records of 30 female patients aged 25-41 years who came to our endocrinology service in the city of Santo André, state of São Paulo, Brazil, to investigate thyroid diseases. The following data were reviewed: total triiodothyronine (totalT3), total thyroxine (totalT4), free thyroxine (FT4), thyroid-stimulating hormone (TSH), and anti-TSH receptor antibodies (anti-TSH receptor or anti-thyrotropin receptor antibodies (TRAb), anti-thyroid peroxidase (A-TPO), and anti-thyroglobulin (A-Tg)). These data were reviewed for 30 patients before and during the three trimesters of pregnancy and during the three months after pregnancy. Results: During gestation, we observed a progressive decrease in the blood values of A-TPO and A-Tg, which reached their lowest values in the third trimester of pregnancy, but after birth, they returned to values statistically equivalent to those before pregnancy. Analyzing the three trimesters and the post-pregnancy period, A-TPO increased 192% between the first trimester and postpartum (p = 0.009); it increased 627% between the second trimester and postpartum (p < 0.001); and it increased >1000% between the third trimester and postpartum (p < 0.001). There was no significant difference in the A-TPO values between the pre- and post-gestational periods (p = 1.00), between the first and second trimesters (p = 0.080), or between the second and third trimesters (p = 0.247). Conclusions: According to the results presented here, we observed changes in the activities of A-Tg and A-TPO antibodies during and after pregnancy in women with previous AITD. In women who intend to become pregnant, are pregnant, or have given birth within three months, it is essential to monitor A-TPO, A-Tg, and thyroid function as well as serum thyroid hormones and TSH to identify thyroid dysfunction in a timely manner and adjust the treatment strategy to avoid the deleterious effects of hypothyroidism on both mother and baby during and after pregnancy.

Do Postpartum Maternal Iodine Status or Supplementation Affect Thyroid Function After Delivery? A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was, for the first time, to explore whether postpartum maternal iodine status or supplementation is associated with thyroid function after delivery. The MEDLINE/PubMed, Web of Science, Embase, and Scopus were searched up to December 2021 to identify relevant studies. The pooled mean thyroid stimulating hormone (TSH), free thyroxine (fT4), and thyroxine (T4) concentrations and 95% confidence intervals (CIs) were estimated based on maternal urinary iodine concentration (UIC) (< 50, 50-100, 100-200, and > 200 µg/L) or breast milk iodine concentration (BMIC) (< 100 µg/L vs. ≥ 100 µg/L) during postpartum. A fixed/random effects model was used based on the absence/presence of heterogeneity, respectively. The study is registered with PROSPERO, number CRD42022336145. A total of 2175 studies were identified, of which 18 were eligible for the meta-analysis. The pooled values for TSH, fT4, and T4 concentrations in all subgroups were within the normal range; however, except for TSH, comparing the 95% CI showed no statistically significant difference among different subgroups. The pooled mean for TSH concentration in women with UIC > 200 µg/L was 2.23 mIU/L, whereas the corresponding values in women with UIC < 50, 50-100 and 100-200 µg/L were 0.56, 0.56 and 0.95 mIU/L, respectively. Thyroid hormones in women with BMIC < 100 µg/L and ≥ 100 µg/L were within the normal range. Iodine supplementation during postpartum was not associated with any differences in thyroid parameters, compared to non-supplemented women. In conclusion, iodine status or supplementation had no effect on thyroid hormones in postpartum women.

Reference values for biochemical tests during pregnancy: analysis of the PRECAREbio Cohort and correlation with precarious status

OBJECTIVE

To establish normal current values of various biochemical parameters during pregnancy in the northern area of Paris (France) in a subgroup from the PreCARE cohort and to study their changes according to the term of pregnancy, and to determine the influence of maternal precarity.

DESIGN

The PreCAREbio cohort of pregnant women was defined in the PreCARE study, a multicenter cohort study.

SETTING

Participants completed detailed questionnaires at enrolment and immediately postpartum. Data were collected prospectively. 26 biochemical parameters were longitudinally assessed.

POPULATION

All women registered to deliver or who delivered at one of the four participating university hospitals in Paris between October 2010 and November 2011 were eligible for study inclusion (n=10,419).

METHODS

We studied 26 biochemical markers during pregnancy and the influence of maternal social deprivation.

MAIN OUTCOME MEASURES

Baseline values for 26 biochemical markers and their changes according to the term of pregnancy, and the influence of maternal social deprivation on these biochemical markers.

RESULTS

386 patients with 1733 blood samples recruited in one of the four centers in the PreCARE cohort were included. Baseline concentrations (median, 2.5th and 97.5th percentile) for each marker and did not differ at the different time points. Mean concentrations of each biochemical marker did not differ between socially deprived women and non-socially deprived women.

CONCLUSIONS

We have established normal values for 26 biochemical parameters during pregnancy. We have also shown no difference in these values between socially deprived and non- socially deprived women.

Levothyroxine Treatment in Pregnant Women with Thyrotropin Levels Ranging Between 2.5 and 10 mIU/L: A Propensity Score Matched Analysis

Objective: To clarify the association between levothyroxine (LT4) treatment and various adverse pregnancy outcomes in pregnant women with thyrotropin (TSH) levels ranging between 2.5 and 10.0 mIU/L in the first trimester, stratified according to thyroid peroxidase antibody (TPOAb) positivity and TSH level. Methods: This retrospective analysis of retrospectively and prospectively collected cohort data included Chinese pregnant women with TSH levels of 2.5-10 mIU/L and normal free thyroxine levels (11.8-18.4 pmol/L) in the first trimester. All participants were followed up until the completion of pregnancy, and information on LT4 treatment, pregnancy complications, and pregnancy outcomes was recorded. A 1:1 nearest-neighbor propensity score matching (PSM) between the LT4-treated and - untreated groups with a caliper distance of 0.02 was performed using a multivariable logistic regression model. Multivariable-adjusted modified Poisson regression was used to estimate the relative risk (RR) and 95% confidence interval (CI) of LT4 treatment for adverse pregnancy outcomes. Subgroup analyses were also performed in four subgroups simultaneously stratified by TPOAb status (negative or positive) and TSH levels (2.5-4.0 mIU/L as high-normal group and 4.0-10.0 mIU/L as SCH group). The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100047394). Results: Among the 4,370 pregnant women in the study, 1,342 received LT4 treatment and 3,028 did not. The 1:1 PSM yielded 668 pairs of individuals and revealed that LT4 treatment was significantly associated with a decreased risk of pregnancy loss (RR = 0.528, 95% CI: 0.344-0.812) and an increased risk of small-for-gestational-age infants (RR = 1.595, 95% CI: 1.023-2.485). Subgroup analyses suggested that the above effects of LT4 treatment were mainly from TPOAb-negative participants. LT4 treatment was associated with an increased risk of preterm birth (RR = 2.214, 95% CI: 1.016-4.825) in TPOAb-positive pregnant women with high-normal TSH levels. Conclusion: LT4 treatment was significantly associated with a lower risk of pregnancy loss and a higher risk of small-for-gestational-age infants in pregnant women with TSH levels of 2.5-10 mIU/L. An increased risk of preterm birth was observed in the LT4-treated group among TPOAb-positive participants with TSH levels of 2.5-4.0 mIU/L.

Australasian Recurrent Pregnancy Loss Clinical Management Guideline 2024 Part I

Guidelines for the investigation and management of recurrent pregnancy loss (RPL) have been developed in Europe, USA and UK, but there is currently no Australasian guideline. The Australasian Certificate of Reproductive Endocrinology and Infertility Consensus Expert Panel on Trial Evidence group has prepared a two-part guideline to provide guidance on the management of RPL. In Part I chromosomal, anatomical, and endocrine factors are outlined along with relevant recommendations for clinical management, levels of evidence and grades of consensus. In Part II thrombophilia, autoimmune factors, infective, inflammatory, and endometrial causes, environmental and lifestyle factors, male factor and unexplained causes will be outlined.

The Impacts of Inflammatory and Autoimmune Conditions on the Endometrium and Reproductive Outcomes

Background: A healthy pregnancy begins with an adequate endometrial state, even before the arrival of a blastocyst. Proper endometrial priming and the development of a tolerogenic decidua are key steps in creating the perfect environment for implantation and pregnancy. In these processes, the involvement of the maternal immune system seems to be of great relevance, modulating the different decidual immune populations to prepare the endometrium for a potential pregnancy. However, certain local pathologies of an inflammatory and autoimmune nature appear to have a direct impact on these phenomena, thus altering patients' reproductive outcomes. Methods: This literature review analyzes original articles, reviews, systematic reviews, and meta-analyses published between 1990 and 2024, concerning the impact of different inflammatory and autoimmune conditions on endometrial status and fertility. The included papers were obtained from Medline (Pubmed) and the Cochrane library. Results: There is evidence that endometriosis, adenomyosis, and chronic endometritis, through the promotion of a chronic inflammatory environment, are capable of altering endometrial immune populations, and, thus, processes essential for early pregnancy. Among other effects, these conditions have been linked to impaired decidualization, alterations in progesterone responsiveness, and hindered placentation. Similarly, antiphospholipid syndrome (APS), thyroid dysfunction, diabetes, and other pathologies related to glucose and gluten metabolism, due to their autoimmune nature, also appear to have a local impact on the uterine environment, affecting reproductive success through different mechanisms, including altered hormonal response and, again, impaired decidualization. Conclusions: The management of inflammatory and autoimmune diseases in assisted reproduction patients is gaining importance due to their direct impact on the endometrium. It is necessary to follow current expert recommendations and established therapeutic approaches in order to improve patients' prospects, ranging from antibiotic treatment in chronic endometritis to heparin and aspirin in APS, as well as hormonal treatments for endometriosis/adenomyosis or a gluten-free diet in celiac disease. All of them and the rest of the therapeutic perspectives, both current and under investigation, are presented throughout this work, assessing the possible improvements for reproductive outcomes.

Clinical features of neonatal hyperthyroidism: a retrospective analysis in southwestern China

Purpose

This study aimed to explore the clinical characteristics and evaluate the different types of thyroid dysfunction in babies with neonatal hyperthyroidism.

Methods

The clinical data of 19 neonates with hyperthyroidism admitted to the Children's Hospital of Chongqing Medical University between January 2012 and April 2021 were retrospectively analyzed.

Results

Fifteen (78.9%) infants were born to mothers with Graves' disease. Eleven (57.9%) infants were premature; two babies were born at small for gestational age. The age at diagnosis ranged from 3 to 34 days, with a mean of 18.53 ± 6.85 days. The majority of the babies presented with goiter (84.2%) and tachycardia (94.7%) after birth. Nine (47.4%) of them presented with abnormal weight gain, seven (36.8%) presented with stare or ocular protrusion, six (31.6%) presented with hyperexcitability, four (21.1%) presented with jaundice and liver dysfunction, two (10.5%) presented with sweating, one (5.3%) presented with fever, and one case presented without any symptoms. Transient hyperthyroidism was the main thyroid dysfunction in our study. Overt hyperthyroidism was diagnosed in 13 (68.4%) neonates. Another three babies (15.8%) presented with hyperthyroidism with slightly elevated free triiodothyronine levels, normal thyroxine (T4) levels, and low thyroid-stimulating hormone (TSH) levels. Normal thyroid hormone levels with low TSH levels were observed in three (15.8%) neonates. Ten children were treated with antithyroid drugs. Eighteen children recovered normal thyroid function at 1-3 months of age; one baby in the study group required further levothyroxine supplementation due to primary hypothyroidism (HT). One child was found to have developmental delay at 2 years of age during follow-up.

Conclusions

Our study highlights the need for prolonged monitoring of thyroid function in suspected patients. A single normal screening for hyperthyroidism or the absence of a maternal history of hyperthyroidism cannot exclude this disease.

Defining Trimester-Specific Reference Intervals for Thyroid Hormones: Insights from a Bulgarian Monocenter Study

Background and Objectives: Pregnancy introduces various interfering factors that, alongside individual variations, impact the assessment of thyroid function tests. This underscores the necessity of defining trimester-specific reference intervals for thyroid-stimulating hormone (TSH) levels. Differences in population characteristics, including ethnicity, socio-economic factors, iodine prophylaxis, and obesity, emphasize the need to establish trimester-specific TSH ranges for women of reproductive age in the respective region or center. The aim of the present study was to establish first- and second-trimester-specific reference intervals for TSH and free thyroxine (FT4) in a relevant pregnant population. Materials and Methods: A retrospective monocenter analysis utilized the electronic database of Ob/Gyn Hospital "Dr. Shterev", Sofia, Bulgaria. The analysis involved data from 497 pregnant and 250 non-pregnant women, all without evidence of thyroid dysfunction or a family history thereof, no indication of taking medication interfering with thyroid function, no evidence of levothyroxine treatment, and no history of sterility treatment. To establish the limits of the TSH reference range, the percentile method was applied using a bootstrapping procedure following the recommendations of the International Federation of Clinical Chemistry (IFCC). Results: Trimester-specific reference intervals for TSH and FT4 in our center were established as follows: first trimester-0.38-2.91 mU/L, FT4-12.18-19.48 pmol/L; second trimester-0.72-4.22 mIU/L and 9.64-17.39 pmol/L, respectively. We also established the normal reference range for the non-pregnant control group, which is similar to that applicable in our laboratory. Conclusions: Our results differ from the fixed limits recommended by the American Thyroid Association, European Thyroid Association, and Endocrine Society Guidelines. Following the relevant established intervals would significantly impact timely diagnosis and therapy requirements for a substantial proportion of pregnant women.

Coexistence of Endometriosis and Thyroid Autoimmunity in Infertile Women: Impact on in vitro Fertilization and Reproductive Outcomes

OBJECTIVES

The objective of the study was to evaluate the prevalence and impact of impaired thyroid-stimulating hormone (TSH) levels on the reproductive outcomes of in vitro fertilization patients diagnosed with endometriosis and compared to controls without endometriosis.

DESIGN

This is a retrospective cohort study on prospectively collected data.

SETTING

The study was conducted at tertiary care university hospital.

PARTICIPANTS

Participants were infertile women with histopathological diagnosis of endometriosis.

METHODS

For 12 months (January 2018 to January 2019), women were deemed suitable and subsequently divided according to serum TSH levels above or below 2.5 mIU/L and compared to patients without endometriosis. Needed sample size was at least 41 patients for each cohort of women. Co-primary outcomes were the live birth rate (LBR), clinical pregnancy rate (CPR), and pregnancy loss rate (PLR).

RESULTS

Overall, 226 women (45 with endometriosis and 181 controls without endometriosis) were included. Diagnoses of Hashimoto thyroiditis were significantly more frequent in women with rather than without endometriosis (14/45 [31.1%] vs. 27/181 [14.9%]; p = 0.012). Similarly, in women with endometriosis, Hashimoto diagnosis rates were higher with TSH ≥2.5 mIU/L compared to TSH <2.5 mIU/L (9/15 [60%] vs.5/30 [16.6%]; p = 0.001) so were the Hashimoto diagnosis rates in control group (women without endometriosis) with TSH ≥2.5 mIU/L compared to TSH <2.5 mIU/L (17/48 [35.4%] vs. 10/133 [7.5%], respectively; p = 0.001). Effect size analysis confirmed an increased risk of Hashimoto thyroiditis in women with endometriosis and TSH ≥2.5 mIU/L compared to women with endometriosis and TSH <2.5 mIU/L (risk ratio [RR] 3.60 [95% CI 1.46-8.86]) and in women with endometriosis and TSH ≥2.5 mIU/L compared to non-endometriotic euthyroid patients (RR 7.98 [95% CI 3.86-16.48]). Dysmenorrhea risk was higher in endometriotic euthyroid women compared to euthyroid patients with no endometriosis (RR 1.87 [95% CI 1.21-2.87]). The risk was still increased in euthyroid women with endometriosis relative to dysthyroid women with no endometriosis (RR 1.97 [95% CI 1.11-3.50]). There were no significant differences between the four groups for CPR, LBR, PLR and retrieved oocytes, immature oocytes, degenerated and unfertilized oocytes, cultured blastocysts, embryos and transferred embryos.

LIMITATIONS

Limitations of the study were retrospective design, limited sample size, and use of different ovarian stimulation protocol.

CONCLUSIONS

Thyroid autoimmunity seems more common in women with endometriosis and TSH over 2.5 mIU/L. However, there was no significant impact on in vitro fertilization and reproductive outcomes related to the coexistence of endometriosis, Hashimoto disease, and higher TSH levels. Due to limitations of the study, additional evidence is required to validate the abovementioned findings.

Subclinical hypothyroidism in the infertile female population: a guideline

There is controversy regarding whether to treat subtle abnormalities of thyroid function in infertile female patients. This guideline document reviews the risks and benefits of treating subclinical hypothyroidism in female patients with a history of infertility and miscarriage, as well as obstetric and neonatal outcomes in this population.

[Reference levels of thyroid hormones in pregnant woman from Guadalajara]

INTRODUCTION

Thyroid dysfunction during gestation impacts on maternal-fetal health and may influence the neurocognitive development of the child. Thyroid physiology changes during pregnancy and requires the establishment of specific reference levels per trimester and for each population and method. The objectives of our study were to analyse thyroid function throughout pregnancy and to establish reference levels for TSH and T4L in each trimester for our population and methodology.

MATERIAL AND METHODS

Prospective analytical study of 598 pregnant women from March 2018 to October 2020. TSH, T4L, T3L, ATPO and ATG were determined in all of them. A total of 151 pregnant women were excluded due to positive thyroid immunity, previous thyroid disease in treatment with levothyroxine, twin pregnancy, diagnosis of hypothyroidism and hyperthyroidism in the request or absence of some of the parameters studied, with a reference population of 447 pregnant women.

RESULTS

The reference levels for TSH were 0.07-3.14mIU/L for the first, 0.66-3.21mIU/L for the second and 0.52-2.97mIU/L for the third trimester. Reference levels for T4L were 0.81-1.19ng/dL for the first, 0.71-1.07ng/dL for the second and 0.69-1.06ng/dL for the third trimester.

CONCLUSIONS

The reference levels for TSH and T4L obtained in this study differ from those used for the general population, which may have led to misclassification errors and unnecessary treatment in pregnant women.

Effect of Maternal Subclinical Hypothyroidism on Congenital Hypothyroidism Screening Results: A Retrospective Cohort Study

OBJECTIVES

This study aimed to evaluate the results of congenital hypothyroidism screening (CHS) in neonates born to women with subclinical hypothyroidism (SHT) during pregnancy and to identify maternal and neonatal characteristics associated with recall rate in CHS.

STUDY DESIGN

This retrospective cohort study included nonrefugee pregnant women and newborn pairs who underwent thyroid function tests during prenatal follow-up between 2014 and 2017 and had neonatal CHS records. The women were evaluated overall and divided into euthyroidism (ET) and SHT groups according to their thyroid function tests. The groups were compared in terms of CHS results. Neonates with thyroid-stimulating hormone (TSH) levels <5.5 mIU/L were considered "normal," while those with values ≥5.5 mIU/L were "recall."

RESULTS

The antenatal thyroid function data of a total of 22,383 pregnant women were analyzed. Of these, 71.6% were ET and 16.3% were diagnosed as SHT. Overall, the recall rate accounted for 5.34% of all CHS results and the recall rate was higher in the SHT group (7.10%) compared with the ET group (5.54%; p = 0.001). Being low birth weight (LBW) or large for gestation age (LGA), maternal TSH above the 97.5th percentile, and cesarean delivery increased the risk of recall in CHS (p ˂ 0.05).

CONCLUSION

The recall rate was higher among the neonates of mothers with SHT. Being LBW or LGA, maternal TSH above the 97.5th percentile and cesarean delivery increased the risk of recall in CHS.

KEY POINTS

· SHT is the most common form of hypothyroidism in pregnancy.. · TSH elevation is higher among the neonates of mothers with SHT.. · Being LBW or LGA, and cesarean delivery also increase the risk of TSH elevation in infants..

Effects of Levothyroxine Treatment on Fertility and Pregnancy Outcomes in Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Subclinical hypothyroidism, defined by elevated thyrotropin (TSH) and normal free thyroxine levels, is associated with adverse pregnancy outcomes, including preterm birth, pre-eclampsia, and small for gestational age. Despite the uncertainty regarding the effectiveness of levothyroxine (LT4) treatment on pregnancy outcomes in subclinical hypothyroidism, LT4 is widely administered with a pre-treatment threshold TSH level of 2.5 mU/L. The aim of this study is to investigate the efficacy of periconceptional LT4 treatment for subclinical hypothyroidism, including TSH levels >2.5 mU/L, and identify the characteristics of subclinical hypothyroidism that can benefit from LT4 treatment. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials from inception to February 2023. We analyzed the pooled effects of LT4 on subclinical hypothyroidism before and during pregnancy. The main outcomes before pregnancy were live birth, pregnancy, and miscarriage. The main outcomes during pregnancy were live birth, miscarriage, and preterm birth. We conducted subgroup analyses to compare the effects of LT4 on subclinical hypothyroidism with TSH levels of 2.5-4.0 and >4.0 mU/L. Results: Of the 888 studies identified, 27 full-text articles were screened for eligibility. Five studies on pre-conception treatment with 768 participants and eight studies on treatment during early pregnancy with 2622 participants were analyzed. One of the two studies on pre-conception treatment in subclinical hypothyroidism with TSH >4.0 mU/L had high risk of bias and the other was composed of 64 participants. Pre-conception LT4 treatment had no significant effect in improving rates of live births and pregnancies, or reducing miscarriages (risk ratio [RR], 95% confidence interval): 1.41 (0.84-2.36), 1.73 (0.88-3.39), and 0.46 (0.11-2.00), respectively. LT4 treatment during pregnancy was not significantly associated with higher rates of live births (RR 1.03, 0.98-1.09) nor decreased miscarriage rates (RR 1.01, 0.66-1.53). The effect of LT4 treatment on preterm birth during pregnancy was significantly different depending on the TSH values (p = 0.04); a positive effect was shown in the subclinical hypothyroidism subgroup with TSH >4.0 mU/L (RR 0.47, 0.20-1.10), while no significant effect was observed in the subgroup with TSH 2.5-4.0 mU/L (RR 1.35, 0.79-2.31). Conclusions: Pre-conceptional LT4 treatment for subclinical hypothyroidism does not improve fertility or decrease the incidence of miscarriages. However, further well-designed studies are needed for pre-conceptional treatment, especially in TSH >4.0 mU/L. LT4 treatment during pregnancy had a positive effect on preterm birth; nevertheless, this was only applicable to subclinical hypothyroidism with TSH >4.0 mU/L.

Neonatal Graves disease with persistent hypoglycemia: A case report

Neonatal Graves disease is the most common cause of hyperthyroidism during the newborn period. Maternal Graves disease increases the risk of intrauterine growth restriction, small for gestational age, and neonatal Graves disease. Intrauterine growth restriction and small for gestational age are associated with hypoglycemia and transient neonatal hyperinsulinism. Neonatal Graves disease with severe persistent hypoglycemia has not been well described. We present the case of a female patient born at 34 weeks and 3 days with a birth weight of 1.6 kg (fifth percentile) to a mother with recent treatment for Graves disease. Prenatal ultrasounds were significant for intrauterine growth restriction and small for gestational age. The mother did not begin hyperthyroidism medical therapy until 23 weeks and 2 days of gestation. After the infant was born, the infant not only had symptoms of hyperthyroidism such as tachycardia and abnormal thyroid values but also had persistent hypoglycemia, which could be due to maternal propranolol usage, prematurity, IUGR, increased metabolism due to neonatal Graves, and transient stress-induced hyperinsulinism. The infant was started on methimazole for hyperthyroidism and propranolol for tachycardia. She was also started on diazoxide for persistent hypoglycemia. By 6 months of age, the hyperthyroidism and hypoglycemia had resolved. This is an interesting case of neonatal Graves disease with severe persistent hypoglycemia which we suspect is due to transient neonatal hyperinsulinism induced by multiple stress responses.

TSH and FT4 Reference Interval Recommendations and Prevalence of Gestational Thyroid Dysfunction: Quantification of Current Diagnostic Approaches

CONTEXT

Guidelines recommend use of population- and trimester-specific thyroid-stimulating hormone (TSH) and free thyroxine (FT4) reference intervals (RIs) in pregnancy. Since these are often unavailable, clinicians frequently rely on alternative diagnostic strategies. We sought to quantify the diagnostic consequences of current recommendations.

METHODS

We included cohorts participating in the Consortium on Thyroid and Pregnancy. Different approaches were used to define RIs: a TSH fixed upper limit of 4.0 mU/L (fixed limit approach), a fixed subtraction from the upper limit for TSH of 0.5 mU/L (subtraction approach) and using nonpregnancy RIs. Outcome measures were sensitivity and false discovery rate (FDR) of women for whom levothyroxine treatment was indicated and those for whom treatment would be considered according to international guidelines.

RESULTS

The study population comprised 52 496 participants from 18 cohorts. Compared with the use of trimester-specific RIs, alternative approaches had a low sensitivity (0.63-0.82) and high FDR (0.11-0.35) to detect women with a treatment indication or consideration. Sensitivity and FDR to detect a treatment indication in the first trimester were similar between the fixed limit, subtraction, and nonpregnancy approach (0.77-0.11 vs 0.74-0.16 vs 0.60-0.11). The diagnostic performance to detect overt hypothyroidism, isolated hypothyroxinemia, and (sub)clinical hyperthyroidism mainly varied between FT4 RI approaches, while the diagnostic performance to detect subclinical hypothyroidism varied between the applied TSH RI approaches.

CONCLUSION

Alternative approaches to define RIs for TSH and FT4 in pregnancy result in considerable overdiagnosis and underdiagnosis compared with population- and trimester-specific RIs. Additional strategies need to be explored to optimize identification of thyroid dysfunction during pregnancy.

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.

Impact of levothyroxine therapy for maternal subclinical and overt hypothyroidism on early child neurodevelopment: A prospective cohort study

OBJECTIVE

Treatment indication of maternal subclinical hypothyroidism (SCH) is undetermined, despite the wide administration of levothyroxine for maternal overt hypothyroidism (OH). This study aimed to evaluate the therapeutic effect of levothyroxine for maternal SCH and OH in real-world practice, with a focus on early child neurodevelopment.

DESIGN

Prospective cohort study.

PATIENTS AND MEASUREMENTS

Pregnant women diagnosed with SCH at the first antenatal visit were enroled and compared to those diagnosed with OH. Thyroid follow-ups were conducted during pregnancy. Early child neurodevelopment was assessed using the Gesell Development Diagnosis Scale (GDDS) at 1, 3, 6, 12 and 24 months of age.

RESULTS

From January 2012 to December 2013, a total of 442 pregnant women were included in final analysis, among whom 194 and 248 were assigned to the SCH and OH groups, respectively. The percentage of levothyroxine therapy at the first antenatal visit was significantly lower in the SCH group than that in the OH group (91.24% vs. 97.58%, p < .01), with a similar treatment rate at delivery (99.4% vs. 100%, p > .05). Notably, GDDS scores were lower in the SCH group than those in the OH group at 6 months to 2 years of age, which was confirmed by subgroup analyses and sensitivity analyses.

CONCLUSIONS

Children born with maternal SCH demonstrated slightly lower neuropsychological scores at 6 months to 2 years of age compared to those with maternal OH in the clinical practice. The therapeutic effect of maternal SCH on the child neurodevelopment requires further exploration.

Elevated Thyroglobulin Antibody Level is Associated with Decreased Anti-Müllerian Hormone in Women of Reproductive Age

Purpose

Women with Hashimoto's thyroiditis (HT) have an increased risk of ovarian insufficiency. However, whether thyroid antibodies affect the ovarian reserve remains controversial. The aim of this study was to explore the possible relationship between anti-Müllerian hormone (AMH) and thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) levels in women of reproductive age.

Methods

A total of 483 women between 18 and 45 years old who had their TPOAb, TgAb, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and AMH levels measured on the same day were enrolled in this study. The levels of TSH, FT4, TPOAb, and TgAb, the prevalence of overt and subclinical hypothyroidism, and the positive rate of TPOAb and TgAb were compared between patients with low (below the 10th percentile), normal (10th to 90th percentile), and high (higher than the 90th percentile) AMH levels.

Results

The median AMH level was 1.72 (0.33-4.27) ng/mL. A total of 9.9% of patients had low AMH levels. The TgAb levels and the prevalence of TgAb positivity were higher in the low AMH group (37.62 (13.10-232.68) IU/mL, 35.42%) than in the normal (12.46 (10.0-67.04) IU/mL, 19.59%) and high (13.61 (10.0-95.74) IU/mL, 23.4%) AMH groups (p=0.001, p=0.040, respectively). Serum AMH levels were inversely correlated with TgAb levels (r = -0.114, p=0.013).

Conclusion

The AMH of women of reproductive age is affected by HT. Furthermore, women with the lowest AMH level had higher levels of TgAb and a positive rate of TgAb, and high TgAb levels may cause autoimmune damage to the ovaries.

Effects of iodine supplementation on thyroid function parameter: Systematic review and meta-analysis

BACKGROUND

Supplementation is an alternative with potential benefits for the prevention of iodine deficiency in pregnancy.

OBJECTIVE

To evaluate the effects of iodine supplementation on maternal thyroid hormone concentrations and iodine status during and/or before pregnancy.

METHODS

The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The search was conducted in the databases: Cochrane, Embase, Pubmed/MEDLINE and Scopus. Studies involving pregnant women of all trimesters who received oral iodine supplementation were included. Study selection was performed in the Rayyan program. Risk of bias was assessed by the Joanna Briggs Institute tool. Meta-analysis was performed in R software version 4.0.4.

RESULTS

Eleven articles with low and moderate risk of bias were included. According to the results of the meta-analysis, supplementation of 200 μg/day of iodine was able to change urinary iodine concentration during pregnancy, thus contributing to adequate intake. When evaluating the period when the intervention started, the best time to start supplementation was prior to pregnancy or in early pregnancy.

CONCLUSION

Daily iodine supplementation had satisfactory effects on iodine status and maternal thyroid hormone concentrations. Although supplementation with 200 µg showed positive effects on iodine status in pregnancy, some studies showed no effect. Prospero Registration: CRD42021249307 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=249307).

Comparison of two different TSH-receptor antibody assays: A clinical practice study

Background

Graves' disease (GD) is caused by the production of TSH-receptor (TSHR) stimulating auto-antibodies. Over the years various TSHR-antibody (TRAb) detection assays have been developed. Most clinical laboratories use competitive TSH-binding inhibitory immunoglobulin (TBII) assays, which measure the total amount of stimulating and blocking auto-antibodies. Selective detection of TSHR stimulating auto-antibodies (TSI) was previously only possible with functional cell-based bioassays. However, more recently an automated bridge-based binding assay to more specifically measure TSI has become available. The aim of our study was to compare the third-generation automated competitive immunoassay (TBII) with the automated bridge immunoassay (TSI) in clinical practice in an academic thyroid expert center.

Methods

A retrospective study in 356 patients with Graves' disease, Graves orbitopathy (GO), and other (thyroid) disease treated in an academic thyroid center was performed. All samples were analyzed for TBII and TSI. For both assays, sensitivity, specificity, positive predictive value (PVV), negative predictive value (NPV) and diagnostic odds ratios were calculated using different cut-offs for negativity.

Results

Using the provided cut-off, the overall sensitivity appeared similar between TBII and TSI, but TSI showed higher overall specificity, PPV, NPV and diagnostic odds ratio. Using two or three times the cut-off for negativity resulted in a decrease in sensitivity, but an increase in specificity and PPV, which was most pronounced for the TBII-assay. Analysis in a subgroup of newly diagnosed treatment naïve GD/GO patients also revealed overall favorable results for the TSI-assay. Increasing the cut-off for negativity resulted in increased specificity for both assays, with similar results using two or three times the cut-off. Most patients with concordant positive results for TBII and TSI suffered from GD or GD + GO (n = 110, 95.6 %), while patients negative for both TBII and TSI mostly suffered from other (thyroid) disease (n = 143, 77.3 %). From patients with positive TBII but negative TSI only 42.1 % had GD/GO (n = 16), whereas 57.9 % (n = 22) had other (thyroid) disease. In contrast, 88.9 % of patients with positive TSI but negative TBII had GD/GO (n = 16), whereas 11.1 % (n = 2) had other (thyroid) disease.

Conclusion

In our academic thyroid center, the diagnostic performance of the TSI-assay outperformed the TBII-assay. Using a higher cut-off value for negativity can be helpful in assessing clinical relevance.

Developmental scores in offspring of women with subclinical hypothyroidism in pregnancy are affected by gender and thyrotropin cutoff

OBJECTIVES

Subclinical hypothyroidism (SCH) is defined by elevated thyrotropin (TSH) and normal level of thyroxine (T4). The definition of SCH and the cutoff for TSH normality in pregnancy are debated. In the present study, we assess offspring perinatal outcome, anthropometrics and early development in relation to different TSH levels.

METHODS

An observational study with 77 singleton-pregnant women included by thyroid screening before a planned cesarean section. Two TSH-cutoffs (3.0 and 3.7 mIU/L) defined euthyroid and SCH groups, and were applied to evaluate offspring anthropometrics, complication rates (maternal blood loss, Apgar-score, cord arterial-pH, admission to neonatal intensive care unit, perinatal hypoglycemia) and offspring development. Development was evaluated by Bayley-III test in a subsample at age 6 months (n=27) and 15 months (n=22).

RESULTS

Prevalence of SCH was 31.2 % at TSH-cutoff 3.0 mIU/L, and 16.9 % at TSH-cutoff 3.7 mIU/L. No differences in complications and anthropometrics were observed. In Bayley-III tests, cognitive score was decreased at 6 months (p=0.012) and at 15 months (p=0.056) by applying TSH-cutoff 3.0 mIU/L. At cutoff 3.7 mIU/L, motor score was decreased at 15 months (p=0.020). Male offspring had significantly lower cognitive scores at age 6 and 15 months (TSH-cutoff 3.0 mIU/L), and motor scores at age 15 months (TSH-cutoff 3.7 mIU/L).

CONCLUSIONS

The importance of the definition of thyroid normality in pregnancy is underlined. This study suggests that a gender-effect might be present in maternal thyroid disease, and that developmental differences exist if TSH-cutoff is low. Further research is needed.

Maternal thyroid peroxidase antibody positivity and its association with incidence of low birth weight in infants

Background

Autoimmune thyroid disease is a prevalent condition affecting women of reproductive age, leading to thyroid dysfunction and impacting pregnancy outcomes. While the critical role of thyroid hormone in pregnancy outcomes is well-established, the potential association between positive anti-thyroid peroxidase antibodies (TPOAb) and adverse pregnancy outcomes in pregnant women with normal thyroid function remains unclear.

Objective

This study aims to investigate the relationship between maternal TPOAb positivity and adverse pregnancy outcomes with normal thyroid function.

Methods

We collected baseline information from pregnant women who visited our hospital between February 2009 and June 2012. Blood samples were taken to measure thyroid stimulating hormone (TSH), free thyroxine (FT4), TPOAb, and anti-thyroglobulin antibodies (TGAb). The incidence of adverse pregnancy outcomes was compared between TPOAb-positive and TPOAb-negative groups among participants with normal thyroid function.

Results

A total of 7,046 pregnant women with normal thyroid function were included, comprising 6,700 with negative TPOAb and 346 with positive TPOAb. The TPOAb-positive group exhibited a higher age (26.0 vs. 27.0 years, p = 0.02) and greater serum TSH levels (1.72 vs. 1.94 mIU/L, p = 0.029), while the gestational week of blood collection was lower (31.9 vs. 26.5 weeks, p = 0.001). Univariate analysis revealed a higher incidence of low birth weight (LBW) in offspring of TPOAb-positive women compared to the TPOAb-negative group (3.5% vs. 1.9%, p = 0.035). After adjusting for confounding factors such as age, gestational week of blood collection, menstrual history, education level, gestational diabetes, gestational hypertension, TGAb, TSH, and FT4, TPOAb positivity emerged as an independent risk factor for LBW infants (OR: 2.317, 95% CI: 1.057-5.076, p = 0.036), while other adverse pregnancy outcomes did not show a significant correlation with TPOAb positivity.

Conclusion

Our findings suggest that TPOAb-positive pregnant women with normal thyroid function are more likely to deliver LBW infants. Regular monitoring of TPOAb-positive pregnancies and timely interventions throughout all stages of pregnancy are crucial.

Subclinical hypothyroidism in pregnancy - assessment of offspring thyroid status and mitochondrial robustness to stress

Subclinical hypothyroidism's clinical implications on pregnancy are controversial. Consequently, thyrotropin (TSH) cutoff-values for pregnancy are continuously a subject for debate. In subclinical hypothyroidism, altered levels of thyroid hormones may affect mitochondrial function.Objectives were i) to analyze thyroid hormone levels in offspring of women with and without subclinical hypothyroidism ii) to analyze mitochondrial "robustness" in terms of MTG/TMRM ratio in pregnant women and their offspring in relation to thyroid function and iii) to perform differentiate analyses on different TSH thresholds to determine the importance of cutoff-values to results.Pregnant women were included by blood collections prior to a planned cesarean section, and cord samples were collected after delivery. Thyroid status (analyzed by Siemens Healthcare Diagnostics by an electrochemical luminescent immunoassay based on LOCI-technology) grouped the women and their offspring in euthyroid or subclinical hypothyroid, with groups established from previous recommended third-trimester cutoff-value (TSH > 3.0 mIU/L) and the recently recommended cutoff-value in Denmark (TSH > 3.7 mIU/L). Flow cytometric measurements of mitochondrial function in mononuclear blood cells with the fluorophores TetraMethylRhodamine Methyl Ester (TMRM) and Mitotracker Green (MTG) were used to evaluate mitochondrial robustness as the MTG/TMRM ratio.No significant differences in mitochondrial robustness between euthyroid and subclinical hypothyroid cohorts were observed, irrespective of TSH-cutoff applied. Maternal and cord MTG/TMRM ratios were positively correlated. Cord-TSH was elevated in subclinical hypothyroid offspring, independent of TSH cutoff applied. Cord-TSH was associated with maternal TSH-level, maternal smoking and cord arterial-pH.

Reducing the Rate of Premature Births through Early Diagnosis and Pregnancy-Adapted Treatment of Hypothyroidism

Introduction

The aim of this study was to determine the extent to which regular monitoring of maternal free thyroxine level and pregnancy-adapted L-thyroxine replacement therapy before and during pregnancy in patients with existing or newly diagnosed latent and manifest hypothyroidism as well as hypothyroxinemia can influence the rate of premature births.

Materials and Methods

This is a retrospective cohort study assessing 1440 pseudonymized survey questionnaires to evaluate the risks of premature birth with two study groups from the same medical practice, and a nationally recruited control group. Study group A (n = 360) had already been taking L-thyroxine prior to conception, study group B (n = 580) started taking it after conception. Both study groups had a maximum gestational age of 12 + 0 GW. In the study groups, TSH and free thyroxine levels were determined regularly for dose adjustment purposes. The aim was to keep the free thyroxine level in the euthyroid hyperthyroxinemic range within the pregnancy adapted reference range. The control group (n = 500) had taken L-thyroxine during pregnancy according to criteria that were not known, as the questionnaire did not include any questions regarding this matter. Taking other risk factors into account, the influence of pregnancy-adapted L-thyroxine replacement therapy on the rate of premature births was determined using logistic regression analysis.

Results

Compared with the control group, the premature birth rate was 70% lower (p < 0.0001) in study group A and 42% lower in study group B (p = 0.0086), while the odds ratio, at 3.46, was particularly significant in study group A. High blood pressure (odds ratio 5.21), body mass index per kg/m 2 (odds ratio 0.91) and S. p. premature birth were identified as other independent risk factors.

Conclusion

The results show an association between more intensive thyroid diagnostics and pregnancy-adapted L-thyroxine replacement therapy and a decrease in premature births. Further studies should be conducted to confirm these results.

Maternal Urinary Iodine Concentration during Pregnancy and Its Impact on Child Growth and Neurodevelopment: An 11-Year Follow-Up Study

Mild-to-moderate iodine deficiency during pregnancy is prevalent worldwide, but its consequences for maternal and child health are not clear. We aimed to investigate the impact of maternal iodine intake during pregnancy on the child's growth and neurodevelopment. This study involved a cohort of 11-year-old children (n = 70) whose mothers had participated in an iodine intake survey during pregnancy. Gestational, neonatal, anthropometric, intelligence quotient (IQ), and socioeconomic parameters were analyzed according to maternal urinary iodine concentration (UIC). There was a positive linear trend of current height Z-score, full-scale IQ, verbal IQ, family income, maternal education, and a negative trend of neonatal TSH levels with increasing maternal UIC levels. However, regression analysis indicated that maternal UIC was not an independent predictor of any gestational, neonatal, or childhood development parameter. Only maternal school education was positively associated with child height and IQ. In conclusion, we did not find any evidence of a direct effect of maternal iodine intake during pregnancy on the long-term growth and neurodevelopment of children. The results suggest that socioeconomic factors are important confounding factors that affect both maternal iodine intake and child development and must be considered when investigating the association between maternal iodine intake and child outcomes.

Preconception Management of Hyperthyroidism and Thyroid Status in Subsequent Pregnancy: A Population-Based Cohort Study

CONTEXT

Optimal thyroid status in pregnancy is essential in reducing the risk of adverse outcomes. The management of hyperthyroidism in women of reproductive age poses unique challenges and it is unclear how preconception treatment strategies impact on thyroid status in subsequent pregnancy.

OBJECTIVE

We aimed to determine trends in the management of hyperthyroidism before and during pregnancy and to assess the impact of different preconception treatment strategies on maternal thyroid status.

METHODS

We utilized the Clinical Practice Research Datalink database to evaluate all females aged 15-45 years with a clinical diagnosis of hyperthyroidism and a subsequent pregnancy (January 2000 to December 2017). We compared thyroid status in pregnancy according to preconception treatment, namely, (1) antithyroid drugs up to or beyond pregnancy onset, (2) definitive treatment with thyroidectomy or radioiodine before pregnancy, and (3) no treatment at pregnancy onset.

RESULTS

Our study cohort comprised 4712 pregnancies. Thyrotropin (TSH) was measured in only 53.1% of pregnancies, of which 28.1% showed suboptimal thyroid status (TSH >4.0 mU/L or TSH <0.1 mU/L plus FT4 >reference range). Pregnancies with prior definitive treatment were more likely to have suboptimal thyroid status compared with pregnancies starting during antithyroid drug treatment (odds ratio 4.72, 95% CI 3.50-6.36). A steady decline in the use of definitive treatment before pregnancy was observed from 2000 to 2017. One-third (32.6%) of first trimester carbimazole-exposed pregnancies were switched to propylthiouracil while 6.0% of propylthiouracil-exposed pregnancies switched to carbimazole.

CONCLUSION

The management of women with hyperthyroidism who become pregnant is suboptimal, particularly in those with preconception definitive treatment, and needs urgent improvement. Better thyroid monitoring and prenatal counseling are needed to optimize thyroid status, reduce teratogenic drug exposure, and ultimately reduce the risk of adverse pregnancy outcomes.

Iodized Salt May Not Be Sufficient to Guarantee an Adequate Iodine Intake in Pregnant Women

Adequate iodine intake is of crucial importance in pregnancy to meet the thyroid hormone needs of both mother and fetus. In the present study, undertaken as a part of the surveillance actions following the introduction in Italy of a national salt iodination program in 2005, the iodine intake was investigated in 123 pregnant women and 49 control women living in the same area of central Italy. All the participants were screened for urinary iodine concentration (UIC), serum level of thyrotropin, free-thyroxine, free-triiodothyronine, and thyroid volume. Moreover, they were provided with a questionnaire on the use of iodine-containing salt or supplements. Control women had a median UIC of 102 µg/L, consistent with an iodine sufficiency, while in pregnant women the median UIC value was 108 µg/L, lower than the endorsed UIC of 150 µg/L. In addition, pregnant women showed a significantly increased median thyroid volume compared to controls. Interestingly, the median UIC did not differ between pregnant women not using iodine-containing salt or supplements and those regularly consuming iodized salt alone, while pregnant women with a daily intake of iodine-containing supplements had an adequate median UIC (168 µg/L). In conclusion, the data reported here showed that pregnant women and their fetuses are still exposed to the detrimental effects of iodine deficiency and that the consumption of iodine-containing supplements should be recommended in pregnancy.

Iodine-induced thyroid dysfunction: a scientometric study and visualization analysis

Objective

Iodine is essential in thyroid hormone production. Iodine deficiency is associated with serious complications (i.e miscarriage and stillbirth), whereas excess can cause thyroid dysfunction (i.e hyperthyroidism, hypothyroidism, thyroid autoimmunity). We conducted this scientometric study to visualize hot spots and trends in iodine-induced thyroid dysfunction over past two decades. The aim of this paper was to help scholars quickly understand the development and potential trend in this field, and guide future research directions.

Methods

Articles on iodine-induced thyroid dysfunction from 2000 to 2022 were retrieved from the Web of Science Core Collection (WoSCC) using the following search terms: (((((TS=(hypothyroid*)) OR TS=(hyperthyroid*)) OR TS= ("TSH deficiency")) OR TS= ("thyroid stimulating hormone deficiency")) AND TS=(Iodine)) NOT TS=(radioiodine). Only publications in English were selected. CiteSpace, VOSviewer, Tableau, Carrot2, and R software were used to analyze the contribution and co-occurrence relationships of different countries, institutes, keywords, references, and journals.

Results

A total of 2986 publications from 115 countries and 3412 research institutions were included. From 2000 to 2022, research on iodine-induced thyroid dysfunction progressed over a three-stage development period: initial development (2000-2009), stable development (2010-2016), and rapid development (2016-2022) period. The Journal of Clinical Endocrinology and Metabolism had the most co-citations followed and China Medical University (n=76) had the most publications. The top three clusters of co-citation references were isolated maternal hypothyroxinemia, subclinical hyperthyroidism, and brain development. Various scientific methods were applied to reveal acknowledge structure, development trend and research hotspots in iodine-induced thyroid dysfunction.

Conclusion

Our scientometric analysis shows that investigations related to pregnant women, epidemiology surveys, and iodine deficiency are promising topics for future iodine-induced thyroid dysfunction research and highlights the important role of iodine on thyroid function.

Expressions of mitochondria-related genes in pregnant women with subclinical hypothyroidism, and expressions of miRNAs in maternal and cord blood

BACKGROUND

Subclinical hypothyroidism in pregnancy and definition by upper thyrotropin (TSH) cutoff are controversial. As mitochondria are influenced by thyroid hormones, the purpose in this study was to measure expression of mitochondria-related genes in euthyroid and subclinical hypothyroid pregnant women to obtain more knowledge of potential metabolic consequences of maternal subclinical hypothyroidism. In addition, we wished to test if applied TSH-cutoff significantly changed our results of expressed gene-levels. Moreover, we aimed to identify potential microRNA-biomarkers for subclinical hypothyroidism - markers that could be traced to offspring as well.

METHODS

From a cohort of at-term pregnant women undergoing planned cesarean section, 77 women had expression levels of the mitochondria-related genes Peroxisome Proliferator-activated Receptor-γ coactivator-1β (PGC-1β), mitochondrial Transcription Factor A (TFAM), Superoxide Dismutase 2 (SOD2) and Nuclear Respiratory Factor 2 (NRF-2) determined by qPCR from blood sampled in prior to delivery. Two TSH-cutoff levels defining subclinical hypothyroidism (> 3.0 and > 3.7 mIU/L) were applied for the procession of results, generating two data analyses of the same cohort. In 22 pairwise maternal-cord samples (subclinical hypothyroid/euthyroid-rate 0.5, TSH-cutoff > 3.0 mIU/L), microRNA-expressions (miRNA) were analyzed.

RESULTS

All gene expressions were lower in the subclinical hypothyroid group regardless of applied TSH-cutoff, but insignificant except for PGC-1β at TSH cutoff > 3.0 mIU/L. Two miRNAs (hsa-let-7d-3p and hsa-miR-345-5p) were upregulated in blood from women and offspring (cord blood) with subclinical hypothyroidism.

CONCLUSIONS

A trend towards decreased mitochondrial gene expressions in subclinical hypothyroidism were demonstrated. The miRNAs hsa-let-7d-3p and hsa-miR-345-5p might be potential markers of maternal subclinical hypothyroidism. However, larger studies are needed to verify the findings.

Burden, risk factors and outcomes associated with adequately treated hypothyroidism in a population-based cohort of pregnant women from North India

Hypothyroidism is the commonest endocrine disorder of pregnancy, with known adverse feto-maternal outcomes. There is limited data on population-based prevalence, risk factors and outcomes associated with treatment of hypothyroidism in early pregnancy. We conducted analysis on data from an urban and peri-urban low to mid socioeconomic population-based cohort of pregnant women in North Delhi, India to ascertain the burden, risk factors and impact of treatment, on adverse pregnancy outcomes- low birth weight, prematurity, small for gestational age and stillbirth. This is an observational study embedded within the intervention group of the Women and Infants Integrated Interventions for Growth Study, an individually randomized factorial design trial. Thyroid stimulating hormone was tested in 2317 women in early (9-13 weeks) pregnancy, and thyroxin replacement started hypothyroid (TSH ≥2.5mIU/mL). Univariable and multivariable generalized linear model with binomial family and log link were performed to ascertain risk factors associated with hypothyroidism and association between hypothyroidism and adverse pregnancy outcomes. Of 2317 women, 29.2% (95% CI: 27.4 to 31.1) had hypothyroidism and were started on thyroxin replacement with close monitoring. Overweight or obesity was associated with increased risk (adjusted RR 1.29, 95% CI 1.10 to 1.51), while higher hemoglobin concentration was associated with decreased risk (adjusted RR 0.93, 95% CI 0.88 to 0.98 for each g/dL) for hypothyroidism. Hypothyroid women received appropriate treatment with no increase in adverse pregnancy outcomes. Almost a third of women from low to mid socio-economic population had hypothyroidism in early pregnancy, more so if anemic and overweight or obese. With early screening and adequate replacement, adverse pregnancy outcomes may be avoided. These findings highlight the need in early pregnancy for universal TSH screening and adequate treatment of hypothyroidism; as well as for attempts to reduce pre and peri-conception overweight, obesity and anemia. Clinical trial registration: Clinical trial registration of Women and Infants Integrated Interventions for Growth Study Clinical Trial Registry-India, #CTRI/2017/06/008908; Registered on: 23/06/2017, (http://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=19339&EncHid=&userName=society%20for%20applied%20studies).

Impact of thyroid-stimulating hormone levels after controlled ovarian hyperstimulation on in vitro fertilization/intracytoplasmic sperm injection outcomes in women with fresh embryo transfer: a prospective cohort study

Objective

Maternal hypothyroidism before and during pregnancy is associated with an increased risk of adverse pregnancy outcomes; many studies have evidenced that controlled ovarian hyperstimulation (COH) triggers a significant increase in the levels of TSH; however, no large-scale prospective studies have evaluated the impact of TSH levels after COH on assisted reproductive technology outcomes. The aim of this prospective study was to investigate whether in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes are affected by TSH levels after COH in women with fresh embryo transfer (ET).

Methods

A total of 664 patients who underwent IVF/ICSI treatment and received fresh ET at the Peking University Third Hospital were included in this study. The rates of clinical pregnancy, miscarriage, live birth, and preterm delivery were analyzed.

Results

The patients were categorized into two groups based on serum TSH levels after COH (0.55 mIU/L < TSH < 2.5 mIU/L: n= 449, 2.5 mIU/L ≤ TSH ≤ 4.78 mIU/L: n= 215). There were no significant differences in the rates of clinical pregnancy, miscarriage, and live birth between the two groups, even after adjusting for age, body mass index (BMI), thyroid antibody positivity, and COH protocols. However, the preterm delivery rate was significantly higher in women with TSH < 2.5 mIU/L than in those with TSH ≥ 2.5 mIU/L, even after adjusting for relevant confounding factors. There was no significant difference in live birth weight between the two groups.

Discussion

Mildly elevated TSH levels (TSH ≥ 2.5 mIU/L) after COH did not affect IVF/ICSI outcomes, and strict control of TSH levels within 2.5 mIU/L after COH might not be necessary. Additionally, strictly controlled TSH levels (TSH < 2.5 mIU/L) may increase preterm delivery risk.

Changes in Drug Clinical Trials of Thyroid Diseases in China, 2009-2022

OBJECTIVE

The incidence rate of thyroid diseases increased worldwide. This study aims to overview the changing landscape of drug clinical trials on thyroid disease during 2009-2022.

METHODS

The detailed information of thyroid disease drug trials registered on the National Medical Products Administration (NMPA) Registration and Information Disclosure Platform for Drug Clinical Studies was searched and collected. The thyroid drug clinical trials were analyzed by the characteristics, time trends, indications, and geographical distribution.

RESULTS

Sixty-five thyroid disease drug clinical trials were launched from 2009 to 2022 in China, which included 21 trials in nontumorous thyroid disease and 44 trials in thyroid carcinoma. The number of registered trials of thyroid diseases including thyroid carcinoma and nontumorous thyroid disease increased steadily from 2009 to 2020. Bioequivalence studies accounted for the largest proportion (32[49.2%]), while phase I and Phase II studies both only accounted for 18.5% (12/65). A significant difference was observed in the trials phase, and randomization between thyroid carcinoma and nontumorous thyroid disease. In terms of clinical indications and drug mechanisms, the number of trials in multi-target tyrosine kinase inhibitors for thyroid carcinoma (n=35) ranked first, followed by thyroid hormone for hypothyroidism (n=7), thyrotropin for thyroid carcinoma (n=6). Sixty-five trials were led by 36 principal investigator (PI) units, and more than 30% of PI-leading units were located in Shanghai (n=7) and Beijing (n=4).

CONCLUSION

During the past 13 years, the development of thyroid diseases drugs trials has achieved certain progress in thyroid carcinoma, especially the molecular targeted therapy, yet the development of drug trials on nontumorous thyroid disease was very slow.

The Diagnostics and Treatment of Recurrent Pregnancy Loss

Recurrent pregnancy loss is a common problem in the reproductive age population of women. It can be caused by many different conditions. This problem is addressed in international guidelines that take a slightly different approach to its diagnosis and treatment. The guidelines used in this review mainly use the guidelines of the Royal College of Obstetricians and Gynaecologists (RCOG), American Society of Reproductive Medicine (ASRM) and European Society of Human Reproduction and Embryology (ESHRE). This review shows how much the approach to miscarriages has changed and how much more needs to be explored and refined. The review also addresses the topic of unexplained pregnancy loss, which continues to be a challenge for clinicians.

Pregnancy outcomes and disease phenotype of hypertensive disorders of pregnancy in singleton pregnancies after in vitro fertilization: a retrospective analysis of 1130 cases

BACKGROUND

Although in vitro fertilization (IVF) can increase the incidence of hypertensive disorders of pregnancy (HDP), the pregnancy outcomes and disease phenotype of HDP in singleton pregnancies conceived via IVF remain unclear.

METHODS

This retrospective cohort study enrolled 1130 singleton pregnancies with HDP from 2016 to 2020. According to the mode of conception, they were allocated into IVF (n = 102) and natural conception (NC) groups (n = 1028). All IVF pregnancies were subdivided into frozen embryo transfer (FET) group (n = 42) and fresh embryo transfer (ET) group (n = 60). Demographic data, pregnancy outcomes and disease phenotypes of HDP among the groups were compared. The risk factors for severe preeclampsia (PE) and early-onset PE were analyzed.

RESULTS

The incidences of early-onset PE (P<0.001), severe PE (P = 0.016), cesarean section (P<0.001) and preterm births (P = 0.003) in the IVF-HDP group were significantly higher than those in the NC-HDP group, and gestational age at diagnosis of HDP (P = 0.027) and gestational age at delivery (P = 0.004) were earlier and birthweight of the neonates (P = 0.033) were lower in the IVF group. In singleton pregnancies with HDP, IVF was associated with increased risks for both severe PE and early-onset PE (aOR 1.945, 95% CI 1.256, 3.014; and aOR 2.373, 95% CI 1.537, 3.663, respectively), as well as FET, family history of preeclampsia, intrahepatic cholestasis of pregnancy, gestational hypothyroidism and multiparity were associated with increased risks of severe PE and early-onset PE.

CONCLUSIONS

In singleton pregnancies with HDP, IVF was associated with an increased incidence of the disease phenotype (severe or early-onset PE), as well as an increased incidence of pregnancy outcomes related to severe PE and early-onset PE.

Iodine Intake From Diet and Supplements and Urinary Iodine Concentration in a Cohort of Pregnant Women in the United States

BACKGROUND

The DRI Estimated Average Requirement (EAR) in pregnancy for Iodine (I), an essential nutrient for fetal neurodevelopment, is 160 μg/d. Supplementation with 150 μg/d I/day is recommended during pregnancy, however, neither dietary intake or the combination of diet and supplement intake has been reported in US pregnant women.

OBJECTIVE

Determine iodine intake from diet and supplements and iodine status in pregnancy by urinary iodine concentration in a large cohort of pregnant women.

DESIGN

Pregnant women (n=750) completed the Diet History Questionnaire 2.0 from the National Institute of Cancer or multiple 24-hour recalls at baseline and identified their prenatal supplement(s). Dietary iodine intake was estimated using the USDA, FDA and ODS-NIH Database for the Iodine Content of Common Foods at enrollment, supplemental iodine intake throughout the study using content databases, and urinary iodine concentration (UIC) by the modified Sandell-Kolthoff reaction in samples collected between 14-20 weeks gestation (n=966).

RESULTS

The median intake of iodine from diet was 108.8 μg/d, and 63% (473/750) were below the Estimated Average Requirement (EAR). Furthermore, 65% (529/818) took a supplement containing iodine, however, only 32% (259/818) took ≥150 μg/d. Median intake increased to 188.5 μg/d with the inclusion of I from supplements, however , 41% (380/925) remained below the EAR even after supplementation suggesting inadequate intake in nearly half of the cohort. A similar 48% (467/966) had UIC ≤150 μg/L.

CONCLUSIONS

Assessment of iodine status by UIC and intake of iodine from diet and supplements support a high prevalence of iodine insufficiency during pregnancy in this large cohort of US women.

Postpartum Thyroiditis Mimicking Central Hypothyroidism: The Perfect Thyming

Hypothyroidism can be seen in postpartum women as a result of central or primary hypothyroidism. Postpartum thyroiditis is a primary hypothyroid condition in which there is likely autoimmune dysfunction leading to damage to the thyroid gland. Patients with postpartum thyroiditis often present with little to no symptoms, and the key to establishing this diagnosis is a comprehensive endocrine workup. We report the case of a 24-year-old postpartum female patient who was diagnosed with postpartum thyroiditis after initial evaluation demonstrated findings concerning central hypothyroidism.

Iodine deficiency and real-life supplementation ineffectiveness in Polish pregnant women and its impact on thyroid metabolism

Introduction

Iodine is a pivotal component of thyroid hormones, and its deficiency leads to negative pregnancy outcomes. Therefore, during gestation, additional iodine supplementation is recommended.

Objectives

By evaluating a group of women from western Poland, the study updated on iodine status during pregnancy and the effectiveness of iodine supplementation in relation to the maternal and neonatal thyroid function.

Patients and methods

A total of 91 women were recruited before the delivery between 2019 and 2021. During the medical interview, the patients declared their dietary supplements intake. Thyroid parameters (TSH, ft3, ft4, a-TPO, a-Tg, and TRAb) were measured in the serum of mothers and in the cord blood of newborns after birth. Urinary iodine concentration (UIC) and urine/creatinine (UIC/crea) ratio were assessed in single urine samples using a validated high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Neonatal TSH screening from dried blood spot was analyzed.

Results

Pregnant women showed a median (interquartile range) UIC of 106 (69-156) µg/liter and UIC/crea ratio of 104 (62-221) µg/g, whereas approximately 20% had UIC/crea below 50 µg/g, indicating iodine deficiency. The iodine supplementation ratio was 68%. No significant differences in UIC, UIC/crea and thyroid parameters were found between iodine supplemented and non-supplemented groups; however, the highest ioduria was detected when iodine was supplemented in addition to levothyroxine in comparison with both substances administered separately. Patients with UIC/crea within 150-249 µg/g demonstrated the lowest TSH and a-TPO levels. Screening TSH was above 5 mIU/liter in 6% of children.

Conclusions

Despite the national salt iodization and the recommendation to supplement iodine during gestation, the status of the abovementioned microelement and real-life intake revealed the ineffectiveness of the current iodine-deficiency prophylaxis model in pregnancy.

Preconception Thyrotropin Levels and Thyroid Function at Early Gestation in Women With Hashimoto Thyroiditis

CONTEXT

Preconception optimization of thyroid function in women with Hashimoto thyroiditis (HT) is highly recommended to prevent/reduce the risk of thyroid insufficiency at early gestation.

OBJECTIVE

This work aimed to evaluate the prevalence of first-trimester thyroid insufficiency in HT women with preconception thyrotropin (T0-TSH) values consistently less than or equal to 2.5 mIU/L with or without levothyroxine (LT4) treatment, and to calculate T0-TSH cutoffs that best preconceptionally identified HT women requiring first-trimester LT4 adjustment/prescription.

METHODS

Serum TSH was obtained at 4- to 6-week intervals from 260 HT pregnant women (122 on LT4 [Hypo-HT]; 138 euthyroid without LT4 [Eu-HT]), prospectively followed from preconception up to pregnancy term. Receiver operating characteristic (ROC) curves were plotted to identify T0-TSH cutoffs best predicting first-trimester TSH levels greater than 2.5 mIU/L (diagnostic criterion [DC] 1) and greater than 4.0 mIU/L (DC 2).

RESULTS

At first trimester, TSH was greater than 2.5 mIU/L in approximately 30% of both Hypo-HT and Eu-HT women, and greater than 4.0 mIU/L in 19.7% Hypo-HT and 10.1% Eu-HT women (P = .038). The optimal ROC-based T0-TSH cutoffs found were 1.24 mIU/L/1.74 mIU/L in Hypo-HT, and 1.73 mIU/L/2.07 mIU/L in Eu-HT women, for DC 1 and DC 2, respectively. T0-TSH values exceeding these cutoffs resulted in a statistically significantly increased risk of first-trimester thyroid insufficiency (odds ratio [OR] [95% CI)] 15.92 [5.06-50.15] and 16.68 [5.13-54.24] in Hypo-HT; 16.14 [6.47-40.30] and 17.36 [4.30-70.08] in Eu-HT women, for DC 1 and DC 2, respectively).

CONCLUSION

The preconception TSH cutoffs that guaranteed a first-trimester TSH less than 2.5 mU/L in hypothyroid- and euthyroid-HT women were, respectively, almost 50% (1.24 mU/L) and 30% (1.73 mU/L) lower than this gestational target, and 1.74 mU/L and 2.07 mU/L in hypothyroid- and euthyroid-HT women, respectively, for a gestational target of 4.0 mU/L.

The Thyroid Hormone Axis and Female Reproduction

Thyroid function affects multiple sites of the female hypothalamic-pituitary gonadal (HPG) axis. Disruption of thyroid function has been linked to reproductive dysfunction in women and is associated with menstrual irregularity, infertility, poor pregnancy outcomes, and gynecological conditions such as premature ovarian insufficiency and polycystic ovarian syndrome. Thus, the complex molecular interplay between hormones involved in thyroid and reproductive functions is further compounded by the association of certain common autoimmune states with disorders of the thyroid and the HPG axes. Furthermore, in prepartum and intrapartum states, even relatively minor disruptions have been shown to adversely impact maternal and fetal outcomes, with some differences of opinion in the management of these conditions. In this review, we provide readers with a foundational understanding of the physiology and pathophysiology of thyroid hormone interactions with the female HPG axis. We also share clinical insights into the management of thyroid dysfunction in reproductive-aged women.

Iodine and Thyroid Maternal and Fetal Metabolism during Pregnancy

Thyroid hormones and iodine are required to increase basal metabolic rate and to regulate protein synthesis, long bone growth and neuronal maturation. They are also essential for protein, fat and carbohydrate metabolism regulation. Imbalances in thyroid and iodine metabolism can negatively affect these vital functions. Pregnant women are at risk of hypo or hyperthyroidism, in relation to or regardless of their medical history, with potential dramatic outcomes. Fetal development highly relies on thyroid and iodine metabolism and can be compromised if they malfunction. As the interface between the fetus and the mother, the placenta plays a crucial role in thyroid and iodine metabolism during pregnancy. This narrative review aims to provide an update on current knowledge of thyroid and iodine metabolism in normal and pathological pregnancies. After a brief description of general thyroid and iodine metabolism, their main modifications during normal pregnancies and the placental molecular actors are described. We then discuss the most frequent pathologies to illustrate the upmost importance of iodine and thyroid for both the mother and the fetus.

Screening and management of major endocrinopathies during pregnancy: an update

Endocrinopathies during pregnancy constitute a challenging issue, being prevalent and requiring appropriate management to avoid maternal and fetal complications. This review aims to summarize and present major endocrine problems during pregnancy, the appropriate screening, maternal monitoring and management, fetal monitoring, and follow-up. Glucose metabolism, thyroid function, as well as calcium and vitamin D metabolism are the main endocrine domains that should be screened and monitored during pregnancy. Gestational diabetes mellitus (GDM) is the most prevalent endocrine disease during pregnancy, followed by thyroid disorders. Specific recommendations are provided for the optimal clinical care of pregnant women and their offspring for GDM, thyroid disorders, and calcium and vitamin D disorders.