Transient Hyperthyrotropinemia Research Articles

A novel useful marker in the early discrimination of transient hyperthyrotropinemia/hypothyroxinemia and congenital hypothyroidism in preterm infants: thyroid-stimulating hormone/free thyroxine ratio.

Transient hyperthyrotropinemia/transient hypothyroxinaemia and congenital hypothyroidism (CH) have completely different treatment and clinical outcomes. However, a powerful, highly sensitive and cost-effective marker for the differentiation of these clinical entities in the early postnatal period is not available. Therefore, we aimed to test the potential, early predictive, diagnostic power of the thyroid-stimulating hormone (TSH)/free thyroxine (fT4) ratio for differentiation of the two clinical entities in the early period of life. TSH and fT4 levels were recorded on the postnatal day 7 of premature infants<32weeks of gestational age. TSH/fT4 ratio was calculated. The significance degree of TSH/fT4 ratio was analyzed for the differentiation of transient hyperthyrotropinemia or transient hypothyroxinaemia and CH. The study included 1,204 preterm infants<32weeks of gestational age. Of the 1,204 infants, 978 (81.2 %) had normal thyroid function. Eighty-eight infants (7.3 %) were diagnosed with CH and 138 (11.5 %) with transient hyperthyrotropinemia or transient hypothyroxinemia. Initial TSH/fT4 ratio>4.8 was found to be an early diagnostic warning sign with high power in favor of transient hyperthyrotropinemia or transient hypothyroxinemia (AUC value: 0.947) and TSH/fT4 ratio>12.5 (AUC value: 0.999) was found to be an early diagnostic warning sign with high power in favor of CH (p=0.0001). We found for the first time that the TSH/fT4 ratio can be used for the early differentiation of transient hyperthyrotropinemia/transient hypothyroxinaemia and CH in preterm infants without additional cost and with high power.

Thyroid Function in 509 Premature Newborns Below 31 Weeks of Gestational Age: Evaluation and Follow-up

Preterm and low birth weight (LBW) neonates may present with thyroid dysfunction during a critical period for neurodevelopment. These alterations can be missed on routine congenital hypothyroidism (CH) screening which only measures thyroid stimulating hormone (TSH). The objective of this study was to evaluate a protocol for thyroid function screening (TFS) six years after national implementation. Serum TSH and free thyroxine (fT4) were measured during the second week of life in neonates below 31 weeks. Patients with abnormal TFS (fT4 <0.8 ng/dL and/or TSH >5 mU/L) were followed up with repeated tests until normal levels were reported. Patients who were still on levothyroxine (LT4) at three years of age were re-evaluated. Five-hundred and nine neonates were included. Thyroid dysfunction was detected in 170 neonates (33%); CH n=20 (3.9%) including typical CH n=1; delayed TSH elevation CH n=19; hypothyroxinemia of prematurity (HOP) n=15 (2.9%); and transient hyperthyrotropinemia n=135 (26.5%). Twenty-one neonates (4.1%) were treated (20 for CH and 1 for HOP). At 3-year follow-up only three patients were diagnosed with permanent CH and still need treatment. LBW infants tended to have TSH levels higher than those with adequate weight. This protocol was able to detect thyroid dysfunction in preterm neonates who were not identified by the current program based on TSH determination in whole-blood. This thyroid dysfunction seems to resolve spontaneously in a few months in the great majority of neonates, but in some cases LT4 could be needed. There is a critical need for specific guidelines regarding the follow-up and re-evaluation of transient CH in preterm neonates.

Re-Evaluation of the Prevalence of Permanent Congenital Hypothyroidism in Niigata, Japan: A Retrospective Study.

Although newborn screening (NBS) for congenital hypothyroidism (CH) in Japan started more than 40 years ago, the prevalence of CH remains unclear. Prevalence estimations among NBS-positive CH individuals include those with transient hypothyroidism and transient hyperthyrotropinemia, and re-evaluation with increasing age is necessary to clarify the actual incidence. Thus, we re-evaluated the incidence of permanent CH. Of the 106,114 patients who underwent NBS in the Niigata Prefecture, Japan, between April 2002 and March 2006, 116 were examined further due to high thyroid-stimulating hormone levels (>8 mIU/L) and were included in the study. We retrospectively evaluated their levothyroxine sodium (LT4) replacement therapy status from the first visit to 15 years of age. Of the 116 NBS-positive patients, 105 (91%) were initially examined in our department. Of these, 72 (69%) started LT4 replacement therapy on the first visit. Subsequently, 27 patients continued LT4 replacement until 15 years of age after multiple re-evaluations. The prevalence of permanent CH in the Niigata Prefecture during this period was 1 in 2500–3500 children. Ultimately, 62.5% of patients on LT4 replacement discontinued treatment by 15 years of age. This is the first study to clarify the true prevalence of permanent CH in Japan.

Transient hyperthyrotropinemia in outpatient children treated due to acute infections of the respiratory system

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Transient Hyperthyrotropinemia in Outpatient Children with Acute Infections of the Respiratory System.

Background: Diagnostics of thyroid disorders (TD) are frequently based on the measurements of thyroid stimulating hormone (TSH) concentration only. If TSH is outside the reference range, the diagnostic procedure used in patients with TD isintroduced. Observations indicate that in a considerable number of these patients, TD is not confirmed. The aim of the study was to assess the incidence of transient hyperthyrotropinemia in healthy children during acute infections of the respiratory system. Patients and Methods: The study included consecutive children (49 boys and 45 girls), aged 2.2–17.3 years, who visited one General Practitioner (GP) due to respiratory tract infections. The tests: complete blood count (CBC), C-reactive protein (CRP), TSH and FT4 were run on the next day after the visit at the physician’s (initial visit) and ≥2 weeks after recovery. Results: Among these children, elevated TSH values were found in about 10% of patients, and they went back to normal values after recovery. A prospective analysis showed a reduction of TSH values in approx. 65% of all groups and TSH at the follow-up visit was significantly lower. Conclusions: Transient hyperthyrotropinemia was observed in about 10% of children with acute respiratory tract infection. This preliminary finding remains unexplained.

Serial Thyroid Function Test in Very Low Birth Weight Neonates

AbstractThyroid dysfunction is more common in preterm and low birth weight infants, and may be missed if thyroid function test (TFT) is not repeated. Thus, we attempted to study the pattern of thyroid function among very low birth weight (VLBW) infants with birth weight less than 1,500 g by serial TFTs. Serum free thyroxine (FT4) and thyrotropin (thyroid-stimulating hormone [TSH]) levels of VLBW infants were tested on fifth to seventh days of life and repeated after 4 weeks of age. Based on serial FT4 and TSH results, abnormal TFT was classified into four groups—transient hypothyroxinemia of prematurity (THOP), transient hyperthyrotropinemia (THT), delayed TSH rise, and overt congenital hypothyroidism (CH). Stata 15.1 (Stata Corp, Texas, United States) was used for analysis. Ninety-six VLBW infants were enrolled with mean gestational age of 30.5 ± 2.7 weeks and median (interquartile range) birth weight of 1,200 (317) g. Out of 96 cases, 30 (31.2%) infants had abnormal TFT. Ten (10.4%) infants had THOP, 7 (7.3%) infants had THT, 11 (11.5%) infants had delayed TSH rise, and 2 (2.1%) infants had overt CH. There were no significant differences in demographic profile and clinical characteristics between neonates with normal and abnormal TFTs. Five infants required levothyroxine supplementation (two infants with overt CH and three infants with delayed TSH rise). VLBW neonates have higher incidence of CH and delayed rise of TSH in this study. In resource-limited settings, repeating TFTs at least once after 4 weeks of age may be suggested to identify delayed rise of TSH which may need intervention.

Recovery Rate of Hyperthyrotropinemia and Its Associated Factors: A Prospective Observational Study

Introduction:Hyperthyrotropinemia (HT) can be transient or permanent. There is no specific protocol in confirmatory tests to discriminate between transient and permanent forms. The aim of this study was to investigate the prevalence of transient HT and the factors that help to discriminate transient from permanent HT. Methods:This was an observational prospective study in all neonates diagnosed with HT referred to the pediatric clinic of Boali Hospital, affiliated to Islamic Azad University Tehran Faculty of Medicine, Tehran, Iran during September 2017 and January 2019. The recovery rate was investigated during a three-month follow-up while withholding medical treatment. Data were analyzed with SPSS Version 22.0.Results: Totally, 80 neonates (65% girls) were enrolled in this study. Among them, 62 participants (77.5%) recovered without any treatment during the three months of follow-up. The recovery rate was significantly higher in term newborns (p < 0.01). The mean weight of recovered neonates (2767.7 ± 440.2 gr) was significantly higher than that of the neonates who did not recover (2141.7 ± 755.2) (p < 0.01). The mean level of thyroid-stimulating hormone (TSH) of the recovered neonates (9.4 ± 3.0 mIU/L) was significantly lower than in the neonates who did not recover (22 ± 6.5 mIU/L) (p < 0.01). Conclusion: The outcome of HT became mostly permanent in patients with a higher level of TSH. The prematurity and low birth weight were the influential factors on TSH level, which could indirectly increase the risk of HT permanence.

Prevalence of thyroid dysfunction in neonatal population

Background: The objectives of this study was to study the prevalence of thyroid disorders in high risk neonatal populations and to study association of maternal thyroid dysfunction with neonatal thyroid problems and outcome.Methods: This was an observational study, conducted in NICU at Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar. The study included neonates born to mothers with thyroid disorder or with clinical features suggestive of thyroid dysfunction. Neonates with history of maternal thyroid dysfunction were screened at 72 to 96 hrs of postnatal age. Those with TSH &gt;10 mIU/L or free T4 &lt;1.1 ng /ml were followed up after two weeks. The neonates with clinical features suggestive of thyroid dysfunction were screened at presentation and those with abnormal thyroid profile were followed up after two weeks. Results obtained were statistically analyzed using SPSS 17.0 software.Results: Out of 260 neonates screened, 208 neonates were born to mothers with hypothyroidism, 6 neonates had increased levels of TSH during first week which normalised on follow up during third week. One neonate born to hyperthyroid mother, showed increased TSH levels during first week and 2nd week which declined to normal level on follow up at 3rd week. Out of 51 neonates with clinical features suggestive of thyroid dysfunction, born to euthyroid mothers, 3 neonates had increased levels of TSH on presentation which normalised on further follow up. Thus, majority of high risk neonates at birth show transient hypothyroidism.Conclusions: None of the neonate was labelled as hypothyroid, all the 10 neonates showed transient hyperthyrotropinemia.

SAT-453 Delayed TSH Elevation in Small for Gestational Age Infants: A Need for Second Screening?

The incidence of CH with a delayed TSH elevation was higher in ELBW and VLBW infants compared with infants weighing ≥1500 grams. Second screening should be considered in preterm neonates, low birth weight (LBW) and very low-birth weight (VLBW) neonates, ill and preterm newborns admitted to NICU, specimen collection within the first 24 hours of life, and multiple births (particularly same-sex twins). Purpose of this study was to determine incidence of delayed TSH elevation with or without congenital hypothyroidism in SGA infants and to Investigate necessity for second screening. Retrospective analysis was performed. 66 SGA newborns with 34-40 weeks’ gestation born at Keimyung University Dongsan Medical Center from 2015 to 2018 were enrolled. Primary screening was performed 48 hours - 7 days after birth. Second screening including venous TSH and venous free T4 at postnatal 8-40 days. Exclusion criteria were infants with congenital hypothyroidism at primary screening (NBS), descendants of mothers with immune thyroid disease, congenital malformations, renal, hepatic, and metabolic diseases, history of steroid or dopamine usage. Initial NBS were collected onto pre-printed filter at the age of 2-7 days by heel prick. (normal TSH < 10 mIU/L). Second sample was obtained at the age of 8-49 days by venous sampling (normal TSH < 5 mIU/L). TSH and free T4 were measured on venous samples with Cobas 8000 e801 (electrochemiluminescence, Roche, Diagnostics, Basel, Switzerland) using standard methods.Incidence of delayed TSH elevation was 27% (18/66). Of them number of transient hyperthyrotropinemia was 13. Mean TSH at initial elevation was 7.56 mIU/L and median age at initial TSH elevation was 18.6 days. Median age at resolution of TSH elevation was 41.5 days. Number of hypothyroidism undergoing l-thyroxine medication was 5. Mean TSH at initial elevation was 22.1 mIU/L. Median age at initial TSH elevation was 14 days. Mean peak TSH was 23.4 mIU/L.The presence of delayed TSH elevation was not related to very low birth weight. SGA infants might be at a risk of delayed TSH elevation. Considering 2nd screening test within 1 month. Further study with more SGA infants are needed. Limitation of this study was relative small number of patients and iodine status was not considered

Follow-up of infants born to mothers with autoinmune thyroid disease. What should not be screened?

IntroductionThyroid dysfunction is a common problem in pregnant women. It is usually of an autoimmune origin, with Hashimotós thyroiditis and Graveś disease being the most common conditions. Although hormonal changes and transplacental antibody transfer may occur, specific neonatal screening has not been shown to be useful. Patients and methodA prospective study of newborns of women with autoimmune thyroid disease born at a level III university hospital (November 2013–December 2016). Neonates were selected during their stay at the maternity. Babies with perinatal asphyxia were excluded. Data were collected from the clinical histories of mothers and newborns. ResultsA total of 191 neonates were included. Ninety percent of mothers had been diagnosed with autoimmune hypothyroidism. Only 5.8% of newborns had some laboratory disorder, consisting of slightly increased thyroid-stimulating hormone levels, which returned to normal at the age of one month and did not correlate to thyroid peroxidase antibody levels. Transient hyperthyrotropinemia was diagnosed in one newborn and required thyroxin treatment during the first year of life. Among newborns from mothers with Graveś disease, 36.8% had some abnormal laboratory value during the first 7 days of life, but there were no cases of hyperthyroidism and only one of transient hyperthyrotropinemia. ConclusionsExperience at our hospital in screening of newborns from hypothyroid mothers reveals a high number of laboratory controls with a poor diagnostic yield. No relationship was found between thyroid peroxidase antibody levels and thyroid dysfunction. We support the recommendations to continue testing serum thyroid-stimulating hormone and FT4 levels at 48 h of life in newborns of mothers with autoimmune hypothyroidism.

Seguimiento del hijo de madre con patología tiroidea autoinmune. ¿Qué no debemos cribar?

IntroductionThyroid dysfunction is a common problem in pregnant women. It is usually of an autoimmune origin, with Hashimotós thyroiditis and Graveś disease being the most common conditions. Although hormonal changes and transplacental antibody transfer may occur, specific neonatal screening has not been shown to be useful. Patients and methodA prospective study of newborns of women with autoimmune thyroid disease born at a level III university hospital (November 2013-December 2016). Neonates were selected during their stay at the maternity. Babies with perinatal asphyxia were excluded. Data were collected from the clinical histories of mothers and newborns. ResultsA total of 191 neonates were included. Ninety percent of mothers had been diagnosed with autoimmune hypothyroidism. Only 5.8% of newborns had some laboratory disorder, consisting of slightly increased thyroid-stimulating hormone levels, which returned to normal at the age of one month and did not correlate to thyroid peroxidase antibody levels. Transient hyperthyrotropinemia was diagnosed in one newborn and required thyroxin treatment during the first year of life. Among newborns from mothers with Graveś disease, 36.8% had some abnormal laboratory value during the first 7 days of life, but there were no cases of hyperthyroidism and only one of transient hyperthyrotropinemia. ConclusionsExperience at our hospital in screening of newborns from hypothyroid mothers reveals a high number of laboratory controls with a poor diagnostic yield. No relationship was found between thyroid peroxidase antibody levels and thyroid dysfunction. We support the recommendations to continue testing serum thyroid-stimulating hormone and FT4 levels at 48h of life in newborns of mothers with autoimmune hypothyroidism.

AB048. Maternal and neonatal factors associated with transient neonatal hyperthyrotropinemia: Indian context

AB048. Maternal and neonatal factors associated with transient neonatal hyperthyrotropinemia: Indian context

Atopy as a risk factor for subclinical hypothyroidism development in children.

Increased thyroid stimulating hormone (TSH) serum concentration can be a marker of subclinical hypothyroidism (SCH) or transient hyperthyrotropinemia. The aim of our study was to evaluate whether high serum TSH concentrations in allergic children could represent true SCH or isolated and transient hyperthyrotropinemia. We enrolled 620 allergic children (1.11-12.8 years) consecutively attending to our department. They were classified as atopics and non-atopics on the basis of the atopy work-up and, at baseline, they were investigated for thyroid function and low-grade inflammation state. Further, TSH was evaluated after 6 (T1) and 12 (T2) months. Both atopics and non-atopics showed higher SCH prevalence compared to controls (p=0.0055 and p=0.02, respectively), and a significant association between atopy and SCH (OR 10.11, 95% CI 1.36-75.12) was found. Both at T1 and T2, atopics had a significant risk of developing severe SCH compared to non-atopics (RR 1.8, 95% CI 1.39-2.34 and 1.61, 95% CI 1.21-2.14; respectively). Our data may suggest that hyperthyrotropinemia in atopic children could be used as a marker of true SCH.

Frequency of Thyroid Function Disorders among a Population of Very-Low-Birth-Weight Premature Infants

Background: Thyroid function disorders, particularly congenital hypothyroidism (CHT), are important endocrine dysfunctions associated with permanent morbidities. CHT is more prevalent among preterm low-birth-weight neonates compared to term infants with normal weight. Methods: This prospective cohort study was conducted on 126 very-low-birth-weight (VLBW) neonates referred to the neonatal intensive care units (NICUs) of two tertiary referral hospitals affiliated to Isfahan University of Medical Sciences in Isfahan, Iran during 2012-2014. On day five of birth and two, four, and six weeks after birth, blood samples were collected from the infants to determine thyroid function disorders, including transient hypothyroxinemia, neonatal hypothyroidism, transient primary neonatal hypothyroidism, and transient hyperthyrotropinemia. Results: In total, 126 infants with mean gestational age of 30.5±2.29 weeks and mean birth weight of 1246.90±193.58 g were enrolled in this study. Thyroid-stimulating hormone (TSH) level of Conclusion: According to the results of this study, thyroid function disorders are relatively common in preterm VLBW neonates, and serum T4 level is correlated with gestational age in these infants. Therefore, thyroid function tests with a consistent protocol are required for premature infants. It is recommended that further research be performed on larger sample sizes to investigate the prevalence of thyroid function disorders in preterm infants.

Transient Congenital Hypothyroidism in Turkey: An Analysis on Frequency and Natural Course.

Objective: Prevalence of congenital hypothyroidism (CH) in Turkey at birth was reported to be as high as 1:650 in 2008-2010. Incidence rates of permanent and transient CH separately are unknown due to lack of follow-up data. We aimed to evaluate the impact of transient hypothyroidism on increasing incidence of CH and to determine the natural course and the clinical, biochemical, and imaging characteristics of transient CH.Methods: Baseline and follow-up data of the infants with CH detected at screening in six provinces in the Black Sea Region were analyzed retrospectively during a time period covering the years 2008-2010.Results: Among 138 cases (48% female), 16 (12%) showed transient hyperthyrotropinemia which resolved without intervention. Of the treated 122 cases, 63 (52%) had transient CH. While its frequency was 35% in 2008, it increased to 56% in 2009-2010, following a lowering of the thyroid stimulating hormone cutoff value. The frequency was higher in inland provinces than in coast (67% vs. 43%; p=0.01).Clinical characteristics of permanent and transient cases were similar except female-to-male sex ratios (1.5:1 vs. 0.6:1; p=0.02). L-thyroxine was discontinued in 70% of transient cases before 3 years of age at a median age of 19 (2-36) months. The only indication for early discontinuation of treatment was a low L-thyroxine dose, which was 1.25±0.27 µg/kg/day at withdrawal time.Conclusion: Our regional follow-up data showed that more than half of newborns with primary CH had transient thyroid dysfunction. In the majority of cases, discrimination between transient and permanent CH can be made before age 3 years, as indicated by cessation of L-thyroxine treatment.

Can One Predict Resolution of Neonatal Hyperthyrotropinemia?

To identify predictors of transience vs permanence of neonatal hyperthyrotropinemia. We hypothesized that infants with greater severity of perinatal stress are more likely to have transient thyrotropin elevations. We retrospectively studied infants diagnosed with hyperthyrotropinemia between 2002 and 2014, following them for up to 12years after diagnosis. Patients were divided into 3 groups: transient hyperthyrotropinemia (treatment was never prescribed), transient congenital hypothyroidism (treatment started but discontinued), and permanent congenital hypothyroidism (withdrawal unsuccessful or not attempted). We performed univariate and multiple logistic regression analyses, including and excluding infants with maternal thyroid disease. We included 76 infants, gestational age mean (±SD) 34.2 (±5.7) weeks, evaluated for hyperthyrotropinemia. Thirty-five (46%) were never treated, and 41 (54%) received levothyroxine. Of the treated patients, 16 successfully discontinued levothyroxine, and for 25 withdrawal either failed or was not attempted. We found that male patients were almost 5 times more likely than female patients to have transient neonatal hyperthyrotropinemia (OR 4.85; 95% CI 1.53-15.37). We documented greater maternal age (31.5±5.48years vs 26±6.76years, mean±SD, P=.02), greater rate of cesarean delivery (86.7% vs 54.2%; P=.036), and retinopathy of prematurity (37.5% vs 8%; P=.02) in the group with transient congenital hypothyroidism vs the group with permanent congenital hypothyroidism. The results show transience of neonatal thyrotropin elevations in a majority of patients and suggest a possible association of hyperthyrotropinemia with maternal and perinatal risk factors.

The Role of Initial Clinical and Laboratory Findings in Infants With Hyperthyrotropinemia to Predict Transient or Permanent Hypothyroidism

Objective: Studies on the clinical course of children with hyperthyrotropinemia are scarce. We aimed to evaluate the role of presentation findings in such infants to predict eventual outcome.Methods: Files of infants diagnosed as suspicious congenital hypothyroidism (CH) in the neonatal or early infancy period in the past ten years were analyzed retrospectively, and 37 patients (M/F: 20/17) with hyperthyrotropinemia diagnosed at a median age of 3.2 months were included in the study. Criteria for inclusion were: normal free thyroxine (fT4) levels and thyrotropin (TSH) levels between 10-20 μIU/mL during the initial neonatal screening (or TSH<10μIU/mL afterwards). Cases with permanent CH (Group 1) were compared to those with transient hyperthyrotropinemia (Group 2) regarding age at the time of diagnosis, sex, gestational age, birth weight, symptoms, ultrasonographic and scintigraphic findings, initial thyroid function tests, and state of mental and motor development.Results: Of the total group, 20 patients (54%) were eventually diagnosed as permanent CH. T4 doses that maintained normal thyroid function tests were significantly higher at the end of the first and second years of life in this group. Age, TSH and fT4 levels at the time of diagnosis, sex, gestational age, birth weight, symptoms, ultrasonographic and scintigraphic findings, and the state of mental and motor development were similar in the two groups.Conclusions: T4 dose required to maintain a euthyroid state was the only parameter which distinguished between transient and permanent CH.Conflict of interest:None declared.

Maternal and Neonatal Urinary Iodine Status and its Effect on Neonatal TSH Levels in a Mildly Iodine-Deficient Area

Objective: Iodine deficiency and excess are the most important factors that affect screening and recall rates of congenital hypothyroidism. The purpose of this study was to investigate the urinary iodine status in newborns and their mothers and its effects on neonatal thyroid-stimulating hormone (TSH) levels in a mildly iodine-deficient area.Methods: A total of 116 newborns and their mothers were included in the study. Urinary iodine levels were measured from healthy mothers and their babies on the 5th day following birth. Neonatal TSH levels were screened, and TSH and free thyroxine (fT4) levels were measured on the15th day in the recall cases. T4 treatment was started in infants with high TSH and low fT4 levels. These measurements were repeated on the 30th day in these newborns.Results: Ninety-nine percent of the mothers included in the study were using iodized salt. The median urinary iodine level in the newborns was 279 µg/L, while it was 84 µg/L in their mothers. The rate of iodine deficiency among the mothers was 56.8%, and the rate of iodine excess was 8.6%. This rate was 10.3% for iodine deficiency and 61.2% for iodine excess in the newborns. The recall rate at the screening was 9.5% (n=11). The urinary iodine levels were above 200 µg/L in three newborns who had transient hyperthyrotropinemia.Conclusions: Iodine deficiency was more frequently observed in nursing mothers, and iodine excess was more frequently seen in their newborns. The iodine excess noted in the newborns was attributed to the use of antiseptics containing iodine. The iodine excess leads to increases in recall rates, screening costs, and frequency of transient hyperthyrotropinemia.Conflict of interest:None declared.

Maternal Thyroid Dysfunction and Neonatal Thyroid Problems

Aim. To investigate obstetric features of pregnant women with thyroid disorders and thyroid function tests of their newborn infants. Methods. Women with hypothyroidism and having anti-thyroglobulin (ATG) and anti-thyroid peroxidase (anti-TPO) antibodies were assigned as group I, women with hypothyroidism who did not have autoantibodies were assigned as group II, and women without thyroid problems were assigned as group III. Results. Pregnant women with autoimmune hypothyroidism (group I) had more preterm delivery and their babies needed more frequent neonatal intensive care unit (NICU) admission. In group I, one infant was diagnosed with compensated hypothyroidism and one infant had transient hyperthyrotropinemia. Five infants (23.8%) in group II had thyroid-stimulating hormone (TSH) levels >20 mIU/mL. Only two of them had TSH level >7 mIU/L at the 3rd postnatal week, and all had normal free T4 (FT4). Median maternal TSH level of these five infants with TSH >20 mIU/mL was 6.6 mIU/mL. In group III, six infants (6.5%) had TSH levels above >20 mIU/mL at the 1st postnatal week. Conclusion. Infants of mothers with thyroid problems are more likely to have elevated TSH and higher recall rate on neonatal thyroid screening. Women with thyroid disorders and their newborn infants should be followed closely for both obstetrical problems and for thyroid dysfunction.

An Infantile Case of Transient, Severe Hypercholesterolemia with Normalization after Complete Weaning from Breast-feeding

A 20-d-old boy was referred to our department because of hyperthyrotropinemia at neonatal mass screening and diagnosed with neonatal transient hyperthyrotropinemia. A follow-up examination when the patient was 5 mo old revealed severe hypercholesterolemia. Familial hypercholesterolemia was first suspected because of the patient’s significantly high levels of total and low-density lipoprotein cholesterol. The parent’s serum lipid profiles were examined and found to be normal. He was completely breast-fed until 6 mo of age. Breast milk was still the main source of food for a period following weaning. At 14 mo old, the patient was weaned completely from breast milk, and his serum cholesterol levels decreased dramatically. According to the normal lipid profiles of the patient’s parents and the spontaneous normalization of serum cholesterol levels after complete weaning from breast milk, breast-feeding was suggested to be responsible for his transient severe hypercholesterolemia. It is well documented that breast-fed infants have higher serum cholesterol levels than formula-fed infants. However, there is no reported case with severe hypercholesterolemia equivalent to or higher than the levels observed in the case of familial hypercholesterolemia. Although the exact mechanism is unknown, it is necessary to consider that a small number of cases develop severe hypercholesterolemia related to breast-feeding.