Newborn of mothers affected by autoimmune thyroiditis: the importance of thyroid function monitoring in the first months of life

Unusual congenital goiter due to maternal Hashimoto thyroiditis: a case report

Congenital hypothyroidism (CH) is the most common cause of endocrinopathy in the newborn Its incidence lies between 1 in 3,000 and 1 in 2,000, However, congenital goiter is a rare form of presentation. Hypothyroidism secondary to autoimmune etiology is extremely rare, with an incidence of 1:84.700-1:31.000 newborns. Anti-thyroid peroxidase antibodies (TPOAb) are able to cross the placenta but rarely induce hypothyroidism in the newborn, much less goiter. A case of congenital goiter in a male newborn secondary to maternal high TPOAb levels is reported. The mother was diagnosed of Hashimoto thyroiditis prior to the pregnancy. At birth, a grade 3 goiter was detected in the newborn. Laboratory testings revealed hypothyroidism with free thyroxine of 7.6 pmol/L, thyroid-stimulating hormone of 108 mUI/L and high TPOAb levels. Treatment with Levothyroxine was started the second day of life with progressive thyroid function normalization. Neurological development has been normal until the date.

A literature review on the redundancy of additional thyroid function tests in neonates of mothers with hypothyroidism

AIM

Newborn thyroid screening tests are carried out during the first days after birth in many parts of the world. The aim of this review was to assess whether additional thyroid function tests of neonates born to mothers with hypothyroidism are necessary to diagnose newborns with congenital hypothyroidism (CH) missed by the usual screening test.

METHODS

A search in PubMed and Google Scholar databases was conducted for pertinent studies, using relevant keywords. All studies that were published in any language from 1 January 2000 to 30 June 2023 were included. Observational cohort studies were included in the analysis, while case reports and studies not referring to neonates were excluded.

RESULTS

Thirteen studies were identified comprising more than 4400 infants with CH. Studies with the larger study populations recommended against additional testing in healthy infants of hypothyroid mothers. Similar were the results of some smaller retrospective studies. Few studies identified in total 16 infants with CH that were missed on neonatal screening without, though, a definite causative link between the mother's and the infant's thyroid dysfunction.

CONCLUSION

Based on available data, additional thyroid function tests seem redundant in identifying undiagnosed cases of CH. Larger studies are needed to reach a definite conclusion.

Thyroid function in infants born to women with hypothyroidism: An observational study at an Australian tertiary perinatal centre

OBJECTIVE

Concerns have been raised regarding thyroid dysfunction in infants born to women with hypothyroidism including those with autoimmune hypothyroidism. This concern has led to the practice of thyroid function testing in the early neonatal period. We evaluated the practice of performing a routine thyroid function test around 2 weeks of age in all healthy full-term infants (≥37 weeks gestation) born to women with hypothyroidism to identify thyroid dysfunction.

DESIGN, PATIENTS, AND MEASUREMENTS

This retrospective, observational single centre study included full-term infants born to women with hypothyroidism, including non-Graves' autoimmune hypothyroidism, over a 3-year period. Preterm infants and those born to women with Graves' disease or thyroidectomy were excluded.

RESULTS

Of the 790 mother-infant dyads, 780 infants (99%) had normal thyroid function. Only 10 infants (1%) had thyroid stimulating hormone (TSH) levels > 10mIU/L at 2 weeks of age (range 10.25-106.37 mU/L). Of these, follow-up thyroid function normalized in nine infants within 2 weeks. A routine newborn screening test identified congenital hypothyroidism in one infant. No infant born to women with known presence of anti-thyroid antibodies had TSH levels > 10 mIU/L. Thyroid function was normal for most infants where maternal anti-thyroid antibodies were not known (125/133, 94%).

CONCLUSIONS

Infants born to women with hypothyroidism (including autoimmune hypothyroidism) had normal thyroid function in the early neonatal period. A small proportion of infants may develop TSH levels > 10 mU/L that normalizes by 4 weeks of age. The practice of routine thyroid function testing for this cohort in addition to newborn screening test offers no additional benefit.

Neonatal Outcomes of Pregnancies Complicated by Maternal Hyperthyroidism

Objective

This study aimed to determine the proportion, clinical characteristics, hormonal status, median time for normalization of serum thyroxine (FT4) and thyroid-stimulating hormone (TSH) and factors affecting time to thyroid function test (TFT) normalization of neonates born to mothers with maternal hyperthyroidism admitted in our institution.

Methodology

This was a retrospective cohort study that included 170 newborns admitted to the Neonatal Intensive Care Unit (NICU) of Hospital Universiti Sains Malaysia (HUSM) with a history of maternal hyperthyroidism from January 2013 until December 2018. We analyzed their baseline demographic and clinical characteristics, maternal thyroid status and antibody levels. Finally, we analyzed newborn thyroid function and thyroid antibodies.

Results

The proportion of neonates born to mothers with maternal hyperthyroidism was 0.8% (170 of 20,198 neonates within the study period). Seven (4.1%) developed overt hyperthyroidism, while four (2.4%) had thyroid storm. The median time for thyroid function test normalization was 30 days (95% CI: 27.1 to 32.8). The median time for TFT normalization was longer among neonates of mothers with positive thyroid antibodies [46.6 days (95% CI, 20.6 to 39.4)] and of mothers who received anti-thyroid treatment [31.7 days (95% CI, 23.5 to 39.9)].

Conclusion

Neonates born to mothers with hyperthyroidism is uncommon. These babies were observed to have a longer time for normalization of thyroid function tests if their mothers had thyroid antibodies or received anti-thyroid treatment.

Utility of the New Indian Society of Paediatric and Adolescent Endocrinology (ISPAE) Guidelines for Congenital Hypothyroidism Screening in a High Risk Unit

OBJECTIVE

To study the new ISPAE guidelines in neonates with congenital hypothyroidism and present authors' experience in managing these neonates.

METHODS

A retrospective review of all babies who were screened for congenital hypothyroidism in the institution over a period of 5 y was conducted. Details pertaining to maternal risk factors, neonatal risk factors, screening TSH, venous TSH and details of etiological evaluation including: ultrasound thyroid, technetium 99m scintigraphy and anti thyroid peroxidase antibody estimation were retrieved. The cases were assessed using the new ISPAE guidelines.

RESULTS

During the study period, 8107 babies were screened for congenital hypothyroidism, 83 cases had confirmed disease and 47 had established etiology. There is a fair correlation between screening TSH and venous TSH (r = 0.7, p < 0.05). The estimated incidence of congenital hypothyroidism in present series is 1 in 97 cases. Out of the 83 cases, 36 (43.3%), 16 (19.2%) and 31 (37.3%) cases had screening TSH >20 μIU/mL, 6-20 μIU/mL and < 6 μIU/mL, respectively. Out of the 47 babies with screening TSH <20 μIU/mL, 23 (48.9%), 25 (53.1%) and 12 (25.5%) cases had prematurity, maternal thyroid disease and illness, respectively, as risk factors (some babies had more than one risk factor). Of the 83 cases, all of them had venous TSH >10 μIU/mL and five cases had low Free T4 (<1.1 ng/dl). Thus, none of the cases with congenital hypothyroidism were missed on the new ISPAE guidelines.

CONCLUSION

The new ISPAE guidelines for neonatal screening for congenital hypothyroidism are very useful and applicable in Indian neonates.

Infants of Hypothyroid Mothers at Risk of Developing Hypothyroidism: A Cross-sectional Study in Qassim Region of Saudi Arabia

Introduction Hypothyroidism is one of the most prevalent endocrine disorders in women of childbearing age. If it goes untreated, can seriously affect maternal and fetal outcomes.Aim This study aimed to assess the prevalence of hypothyroidism in infants born to hypothyroid mothers and to analyze associated fetal complications.Subjects and methods This is a quantitative cross-sectional study conducted among pregnant mothers at Al Qassim region, Saudi Arabia. Data of pregnant women with clinical hypothyroidism during the last five years 2015-2019 were obtained from visiting records of Endocrine Clinic in Qassim University. These participants were contacted and written informed consents were obtained from the participants after a brief introduction of the study. A comprehensive survey questionnaire was used to collect information about demographic and study variables. Results 153 mothers were enrolled. The most common age group was 31 – 45 years with mostly Saudis (93.5%). Complications during pregnancy were detected among 47.1% of mothers. The most common complication during pregnancy was C-section (26.8%). The prevalence of infants with hypothyroidism was 2.6% while the prevalence of newborn babies with temporary/permanent hypothyroidism was 4.6%. Decreased activity (7.8%) and an increased in weight (5.2%) were the most common symptoms of a child at the time of diagnosis.Conclusion Infants with hypothyroidism were not widely prevalent in this study. Cesarean delivery, gestational diabetes and anemia were some of the most common maternal complications during pregnancy.Keywords  

Impact of maternal thyroid disease on neonatal thyroid status

OBJECTIVES

Prevalence of Maternal and congenital hypothyroidism is on the rise. To present the thyroid stimulating hormone screening results in babies born to hypothyroid mothers and assess the burden, aetiology of hypothyroidism in these babies.

METHODS

All antenatal mothers attending our hospital during the study period were enrolled into the study. Group I includes 249 term babies born to hypothyroid mothers and group II comprises 2154 newborns born to mothers who are euthyroid. Heel prick thyroid stimulating hormone was done for all newborns on day 3 for both groups. Confirmatory venous testing was done for all for babies in group I and screen positives belonging to group II. Evaluation and therapy done as per standard guidelines.

RESULTS

Thyroid stimulating hormone values in the two groups are presented. There was significant correlation between peak maternal thyroid stimulating hormone and neonatal day 3 heel prick in group I (r=0.7, P<0.05). The prevalence of positive screening test in groups I and II was 3.8 and 1.03% (p<0.05) whereas corresponding values for confirmed disease was 4.3 and 0.6%, respectively (p<0.05). Aetiological evaluation revealed both transient hypothyroidism (33.3%) and permanent hypothyroidism (66.6%).

CONCLUSION

4.3% of babies born to hypothyroid mothers develop congenital hypothyroidism; aetiology being both transient and permanent. A venous test by 3 weeks is helpful in these babies to improve case identification.

Thyroid function tests in newborns of mothers with hypothyroidism

Performing thyroid function tests (TFT) at 2 weeks of age in neonates of mothers with hypothyroidism, despite having a newborn screening program, is a debated approach. We examined whether there is an additional clinical benefit in TFT at 2 weeks of age in neonates born to mothers with hypothyroidism, in addition to the neonatal screening program. We performed a retrospective study which included all newborns of mothers with a diagnosis of hypothyroidism and gave birth in a single regional hospital between the years 2010 and 2016. Data were collected from a computerized medical record system of the hospital and the community clinics, and from Israel's national newborn screening program. Main outcome measure was results of serum TFT in comparison to the results of the neonatal screening test. There were 1392 newborns eligible according to the study criteria. Of these, 1033 underwent a newborn screening test, and serum TFT at least 2 weeks after birth. Eight babies with congenital hypothyroidism were detected independently by both the newborn screening program and at the TFT performed at 2 weeks of age.Conclusions: No added clinical benefit was found in retesting newborns of hypothyroid mothers for thyroid function in addition to the newborn screening program. What is Known • Performing thyroid function test 2 weeks after birth is a common practice in newborn to a mother with hypothyroidism. • Neonatal screening program for thyroid function is also done in these newborns. What is New • No newborn was found to have a normal newborn screening test but abnormal serum thyroid function test. • No added clinical benefit was found in retesting newborns of hypothyroid mothers for thyroid function in addition to the newborn screening program.

Update on Neonatal Isolated Hyperthyrotropinemia: A Systematic Review

The purpose of this paper was to systematically summarize the published literature on neonatal isolated hyperthyrotropinemia (HTT), with a focus on prevalence, L-T4 management, re-evaluation of thyroid function during infancy or childhood, etiology including genetic variation, thyroid imaging tests, and developmental outcome. Electronic and manual searches were conducted for relevant publications, and a total of 46 articles were included in this systematic review. The overall prevalence of neonatal HTT was estimated at 0.06%. The occurrence of abnormal imaging tests was found to be higher in the persistent than in the transient condition. A continuous spectrum of thyroid impairment severity can occur because of genetic factors, environmental factors, or a combination of the two. Excessive or insufficient iodine levels were found in 46% and 16% of infants, respectively. Thirty-five different genetic variants have been found in three genes in 37 patients with neonatal HTT of different ethnic backgrounds extracted from studies with variable design. In general, genetic variants reported in the TSHR gene, the most auspicious candidate gene for HTT, may explain the phenotype of the patients. Many practitioners elect to treat infants with HTT to prevent any possible adverse developmental effects. Most patients with thyroid abnormalities and/or carrying monoallelic or biallelic genetic variants have received L-T4 treatment. For all those neonates on treatment with L-T4, it is essential to ensure follow-up until 2 or 3 years of age and to conduct medically supervised trial-off therapy when warranted. TSH levels were found to be elevated following cessation of therapy in 44% of children. Withdrawal of treatment was judged as unsuccessful, and medication was restarted, in 78% of cases. Finally, data extracted from nine studies showed that none of the 94 included patients proved to have a poor developmental outcome (0/94). Among subjects presenting with normal cognitive performance, 82% of cases have received L-T4 therapy. Until now, the precise neurodevelopmental risks posed by mild disease remain uncertain.

Long term outcomes of infants born by mothers with thyroid dysfunction during pregnancy

According to Barker’s hypothesis, sub-optimal conditions during gestation might affect the predisposition for diseases in adulthood. Alteration in endocrine functions during pregnancy, such us thyroid function or glucose metabolism, are not exempt. It is well known that subclinical hypothyroidism and thyroperoxidase antibodies-positive euthyroidism during early pregnancy are associated with increased risk of gestational diabetes mellitus and both conditions influence pregnancy outcome and newborn development and metabolism at short and long terms. Fetal production of thyroid hormones starts from the 12th week of gestational age. The transplacental passage of maternal thyroxine (T4) is therefore essential for the fetal neurological development, especially during the first half of pregnancy. If this passage is interrupted, such as in premature birth, neonates are more susceptible to develop impaired thyroid function, because of physiological immaturity of their hypothalamic-pituitary-thyroid axis, acute illnesses and stressful events (sepsis, invasive procedures, drugs). The aim of this review is to investigate the short and long term effects of maternal dysthyroidisms on term and preterm newborns, with particular attention to the metabolic and thyroid consequences. Metabolic syndrome, higher body mass index and greater waist circumference, seem to be more prevalent in children of TPO-Ab-positive mothers. Maternal hypothyroidism may be associated with higher risk of gestational diabetes and adverse birth outcomes, such as preeclampsia, preterm delivery, fetal death and low birth weight offspring. In adulthood, preterm (< 37 weeks of gestational age) or low birth weight (<2.500 g) newborns seem to be more susceptible to develop gestational diabetes, preeclampsia, type 2 diabetes mellitus and behavioral alterations. (www.actabiomedica.it)

A Detailed Analysis of the Factors Influencing Neonatal TSH: Results From a 6-Year Congenital Hypothyroidism Screening Program

Background: Neonatal thyrotropin (TSH) on dried blood spot (DBS), the most common screening strategy for primary congenital hypothyroidism (CH), is influenced by numerous factors that may hinder a true CH diagnosis. A second test can thus be performed to clarify the initial findings, although its application varies among screening programs. Objectives: The aim of this study was to evaluate the effect of maternal and neonatal factors on neonatal TSH levels and offer practical screening recommendations. Methods: We retrospectively analyzed screening data of 62,132 neonates born in Abruzzo, an Italian region considered mildly iodine deficient, between 2011 and 2016. We then performed a multiple linear regression to model the relationship between TSH (the dependent variable) and 13 independent variables extracted from blood collection cards. Results: Most neonates (53,551 of 62,132, 86%) had normal TSH and no clinical indications for a second screening. A minority (1,423, 2.3%) had elevated TSH in the initial DBS, which was confirmed in 97 cases (7%) on a second screen. The remaining neonates (6,594, 10.6%) had a normal initial TSH but underwent a second test in accordance with screening protocols, and were found to have delayed TSH elevation in 23 cases (0.4%). Those 120 newborns (97 + 23), considered highly suspicious for primary CH, were referred to a pediatrician for confirmatory testing and excluded from subsequent analysis of factors influencing TSH levels. Sex (β regression coefficient, β = 1.11 female to male, 95% CI 1.09, 1.12) and age at collection (β = 0.78 day 5 to days 2-3, 95% CI 0.74, 0.83) affected neonatal TSH, suggesting the utility of specific nomograms. In addition, prematurity (β = 0.85 term to preterm, 95% CI 0.80, 0.91), dopamine use (β = 0.71, 95% CI 0.62, 0.81), and birth weight (β = 1.40 normal vs. very low, 95% CI 1.05, 1.89) strongly influenced neonatal TSH. Conclusions: Neonatal TSH is influenced by several factors supporting the delineation of local sex- and age-adjusted TSH cutoffs, and the universal adoption of a second TSH test in neonates at risk of missed primary CH diagnosis.

[Recommendations for the diagnosis and follow up of the foetus and newborn child born to mothers with autoimmune thyroid disease]

The objective of this document is to review the current recommendations in the management of the foetus and the newborn child born to mothers with autoimmune thyroid disease. In 2017, the American Thyroid Association published guidelines for the diagnosis and management of thyroid disease during pregnancy and post-partum. In this guide, 97 recommendations were made, and an algorithm for the diagnosis and treatment of gestational hypothyroidism was proposed. Also, in this last year, a wide review was been published on the foetal and neonatal approach of the child of a mother with Graves' disease. The importance of the determination of maternal antibodies against thyrotropin receptor in the second half of pregnancy is stressed, in order to adequately stratify the risk in the neonate.

Mild Hypothyroidism in Childhood: Who, When, and How Should Be Treated?

Mild hypothyroidism, also known as subclinical hypothyroidism (SH), is biochemically defined as serum TSH levels above the upper limit of the reference range, in the presence of normal serum concentrations of total T4 and free T4 (FT4). In the neonatal period, mild hypothyroidism can be defined by the presence of a TSH value between 6 and 20 mIU/L and normal FT4 levels. After the neonatal period, SH can be defined mild if TSH ranges between 4.5 and 10 mIU/L. The management of mild hypothyroidism in childhood is challenging. The major concern is to establish whether this condition should always be considered an expression of mild thyroid dysfunction. Indeed, the effects of untreated mild hypothyroidism are still not completely defined. In the neonatal period, concern exists about neurocognitive outcome; in children, although there is no clear evidence of alterations in growth or neurocognitive development, subtle cardiovascular abnormalities have been documented. Therefore, there is still uncertainty about the need of treatment across all ages, and the management should be based on the age of the child, the etiology, and the degree of TSH elevation, as well as on other patient factors. This review updates current evidences on diagnosis and management of mild hypothyroidism in childhood.

Thyroid Function Testing in Neonates With Maternal History of Disease

Maternal history of thyroid disease can cause congenital hypothyroidism due to thyroid-stimulatng hormone (TSH) blocking antibodies. No guidelines exist regarding testing beyond the newborn screen. TSH and T4 levels exhibit significant fluctuations after birth which complicates testing. A total of 561 newborns with thyroid function testing done for maternal history of thyroid disease in the newborn nursery were identified retrospectively via chart review, and thyroid disease status was assessed in 352. Newborn screening data were also obtained. Of these infants, 7 had hypothyroidism with 3 having negative newborn screens. No cases of neonatal graves were identified. The 3 infants with negative newborn screens had TSH levels ranging from 6.58 to 28.4 prior to treatment with levothyroxine. All required treatment beyond age 3 years, despite trial off levothyroxine. Infants with maternal history of thyroid disease may require additional testing beyond the newborn screen. However, providers can consider delaying test until after thyroid levels are more stable.

Risk Factors for the Development of Delayed TSH Elevation in Neonatal Intensive Care Unit Newborns

CONTEXT

Delayed thyrotropin (TSH) elevation (dTSH) is defined as elevated TSH at the second neonatal screening (after normal TSH levels at the initial screening) in premature, low-birth-weight, and ill newborns, mostly in the neonatal intensive care unit (NICU) setting. The pathogenesis of dTSH is elusive.

OBJECTIVE

To identify the risk factors for dTSH development among newborns in the NICU.

DESIGN, SETTING, AND PATIENTS

A retrospective medical record review of neonates with dTSH was conducted in eight university-affiliated NICUs. Two controls were selected for each patient, matched for sex and birth weight. The risk factors for dTSH were identified by univariate analysis, followed by multivariate analysis.

MAIN OUTCOME MEASURES

Maternal variables, types of NICU treatments and procedures, syndromes, and various medical conditions were compared between dTSH patients and their matched controls.

RESULTS

We enrolled 100 dTSH patients and 200 matched controls and 46 variables were compared between the two groups. Twelve risk factors for dTSH were identified on univariate analysis: cesarean section, mechanical ventilation, patent ductus arteriosus (PDA), pneumothorax, and administration of cefotaxime, vancomycin, fluconazole, dopamine, ibuprofen, furosemide, insulin, and packed red blood cells. On multivariate analysis, four risk factors were identified: PDA and vancomycin, insulin, and furosemide administration. In 26 twin pairs, in which one twin had dTSH, all variables presented similarly in both twins.

CONCLUSIONS

Although some variables had direct effects on pituitary-thyroid axis dysfunction, these variables, altogether, reflect the severity of the clinical conditions in the NICU, which is the common basis for dTSH.

Neonatal thyroid function born to mothers living with long-term excessive iodine intake from drinking water

OBJECTIVE

The effects of long-term excessive maternal iodine intake on neonatal thyroid function are less known. This study aimed to assess the effects of maternal excessive iodine intake from drinking water on thyroid functions of both mothers and their neonates.

DESIGN AND METHODS

This observational study was performed in high iodine (HI) areas and adequate iodine (AI) intake areas, including 384 healthy pregnant women in late gestation (mean week 39·3 ± 1·6 weeks) and their newborns. Blood and urine samples were obtained from pregnant women, while cord blood samples were obtained from neonates. Urinary iodine concentration (UIC) and thyroid function were evaluated.

RESULTS

The median maternal UIC was 1241 and 217 μg/l in HI and AI areas, respectively (P < 0·001). The concentrations of serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) in neonates in HI areas were 7·33 mIU/l (range 5·47, 11·06 mIU/l), 2·93 ± 0·59 and 15·03 ± 1·92 pmol/l, respectively, while that were 4·71 mIU/l (range 3·96, 6·04 mIU/l), 2·31 ± 0·28 and 16·50 ± 1·35 pmol/l in AI neonates (P < 0·05). Similar changes were also observed in neonates in HI areas when excluding the effect of maternal thyroid autoimmunity. Cord blood TSH concentration (r = 0·31, P = 0·001) and FT3 concentration (r = 0·43, P = 0·001) were positively correlated with maternal UIC. Cord blood FT4 concentration was negatively correlated with maternal UIC (r = -0·25, P = 0·001). Mothers living in HI areas (β = 0·296, 95% CI: 0·163, 0·255) and with subclinical hypothyroidism (β = 0·360, 95% CI: 0·034, 0·175) contributed to elevated cord blood TSH concentration in neonates, while male neonates were more likely to present with higher TSH concentration compared with female infants (β = -0·760, 95% CI: -0·119, -0·033).

CONCLUSIONS

Excessive iodine intake during pregnancy was associated with an increased rate of hyperthyrotropinaemia in neonates and their mothers, especially in male neonates.

[Maternal autoimmune thyroid disease: relevance for the newborn]

BACKGROUND AND OBJECTIVE

Autoimmune thyroid disease is amongst the most frequent endocrine disorders during pregnancy. It is associated with an increase in perinatal morbidity, congenital defects, neurological damage, fetal and neonatal thyroid dysfunction. Maternal thyroid hormones play a key role in child neurodevelopment. We aimed to evaluate the thyroid function and the clinical course of neonates born from mothers with autoimmune thyroid disease during the first months of life in order to define the follow-up.

PATIENTS AND METHOD

We monitored thyroid function and clinical status during the first months in 81 newborns of mothers with autoimmune thyroid disease; 16 had Graves disease and 65 autoimmune thyroiditis.

RESULTS

A percentage of 4.93 newborns had congenital defects, and 8.64% neonates showed an increase in thyrotropin (TSH) (>9.5 μUI/mL 2 times) and required thyroxin within the first month of life. A 85.7% of these showed a negative newborn screening (due to a later increase of TSH). A higher TSH value in the newborn was related to an older age of the mother, higher levels of thyroid peroxidase (TPO) antibody during pregnancy and lower birth weight. A higher free thyroxine (FT4) value in the newborn was related to fewer days of life and mothers with Graves disease.

CONCLUSIONS

We recommend the evaluation of TSH, T4 and TPO antibodies before 10 weeks in all pregnant women with follow-up if maternal thyroid autoimmunity or disorders is detected. It is also recommended to test children's serum TSH and FT4 at 48 h of life in newborns of mothers with autoimmune thyroid disease and repeat them between the 2nd and 4th week in children with TSH>6 μUI/mL. Careful endocrine follow-up is advised in pregnant women and children if hyperthyroidism is detected.

Hashimoto's thyroiditis in patients with normal thyroid-stimulating hormone levels

Hashimoto's thyroiditis (HT) is one of the most common autoimmune endocrine disorders and often leads to hypothyroidism. It has been shown to substantially affect a patient's quality of life. Associated conditions and diseases were thought to be attributable to hypothyroidism. Yet, many patients still suffer from various symptoms even though all thyroid parameters are within the normal range. Independently of thyroid gland function, HT is associated with a wide range of organ-specific and non-organ-specific autoimmune disorders, as well as other diseases, including neuropsychological/psychiatric deficits, decreased left ventricular performance, disorders of the gut, fibromyalgia and reproductive health issues, among others. The underlying pathomechanisms remain unclear. Future treatment options might include thyroidectomy, selenium administration, prophylactic levothyroxine supplementation and dehydroepiandrosterone. However, further research is warranted to clarify the main pathophysiologic implications of thyroid autoimmunity and also to establish treatment options for euthyroid patients who suffer from HT-related symptoms and diseases.