Fecundity in young adults treated early for congenital hypothyroidism is related to the initial severity of the disease: a longitudinal population-based cohort study

Thyroid impairment and male fertility: a narrative review of literature

PURPOSE

To evaluate the effect of thyroid function on male fertility, focusing on hypo- and hyperthyroidism.

METHODS

A PubMed/MEDLINE, Web of Science, and Scopus research was performed. Original studies in English published online up to 31 May 2023 were selected and reviewed. The final reference list was defined based on the relevance of each paper to the scope of this review.

RESULTS

The available data in animals (31 studies) and human (26 studies) showed conflicting results. However, thyroid dysfunction altered erection and ejaculation both in animal models than in men.

CONCLUSION

Both hypothyroidism and hyperthyroidism seem to cause ejaculation and erectile dysfunction. Hence, Guidelines recommend against the systematic screening for thyroid disorders in the men in sub-fertile couples, but only in men with ejaculation and erectile dysfunction and/or altered semen parameters.

Adult Thyroid Outcomes of Congenital Hypothyroidism

BACKGROUND

More than 40 years have passed since the introduction of newborn screening for congenital hypothyroidism (CH), and many early diagnosed patients have reached adulthood. Their thyroid morphology and function have been little studied. This cross-sectional, observational study was conducted to characterize the thyroid morphology and function of adult CH patients diagnosed in the framework of newborn screening for CH.

METHODS

A total of 103 adult CH patients born after 1979 were enrolled at Ito Hospital, Tokyo, Japan, and were classified into Goiter, Normal gland, and Dysgenesis groups based on ultrasonographic findings. For 60 patients, genetic analysis was performed. Thyroid function test results and the proportion of patients with thyroid nodules were compared among the three groups and between 56 female CH patients and 168 non-CH women matched for TSH levels.

RESULTS

A significantly low serum free T3/free T4 ratio (0.22) was observed in the Dysgenesis group. Thyroid nodules were detected in 14.3% (8/56) of female CH patients, more frequently than in non-CH women. Thyroid nodules were detected the most frequently in the Goiter group (71%, 10/14). Genetic defects were identified in 89% (8/9) of patients belonging to the Goiter group, including thyroglobulin defect (33%, 3/9), thyroid peroxidase defect (33%, 3/9), and dual oxidase 2 defect (22%, 2/9).

CONCLUSIONS

Our results suggest that adults with thyroid dysgenesis on levothyroxine replacement therapy have relative T3 deficiency. Most adults with goitrous CH have genetic dyshormonogenesis. They are at high risk of developing thyroid nodules. Our findings support the current guideline recommendation that CH patients with dyshormonogenesis should undergo periodic thyroid ultrasonography.

Guidelines for Newborn Screening of Congenital Hypothyroidism (2021 Revision)

Purpose of developing the guidelines: Newborn screening (NBS) for congenital hypothyroidism (CH) was started in 1979 in Japan, and early diagnosis and treatment improved the intelligence prognosis of CH patients. The incidence of CH was once about one in 5,000-8,000 births, but has been increased with diagnosis of subclinical CH. The disease requires continuous treatment and specialized medical facilities should conduct differential diagnosis and treatment in patients who are positive by NBS to avoid unnecessary treatment. The Guidelines for Mass Screening of Congenital Hypothyroidism (1998 version) were developed by the Mass Screening Committee of the Japanese Society for Pediatric Endocrinology in 1998. Subsequently, the guidelines were revised in 2014. Here, we have added minor revisions to the 2014 version to include the most recent findings. Target disease/conditions: Primary congenital hypothyroidism. Users of the Guidelines: Physician specialists in pediatric endocrinology, pediatric specialists, physicians referring pediatric practitioners, general physicians, laboratory technicians in charge of mass screening, and patients.

[Neonatal screening for congenital hypothyroidism]

Congenital hypothyroidism (CH) is the leading cause of preventable mental retardation. It is mainly due to thyroid dysgenesis or dyshormonogenesis with normally located gland, and detected at birth in developed countries by systematic neonatal screening. The early treatment of patients with CH has successfully improved the prognosis and management of this disease. An increase in the incidence of congenital hypothyroidism with a normally located gland has been reported worldwide over the last three decades. The etiology of CH with a normally located gland remains elusive and about half of them demonstrate spontaneous resolution of CH within a few months (transient CH). They highlight the need to reevaluate thyroid function during follow-up.

Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines Update-An ENDO-European Reference Network Initiative Endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology

Background: An ENDO-European Reference Network (ERN) initiative was launched that was endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology with 22 participants from the ENDO-ERN and the two societies. The aim was to update the practice guidelines for the diagnosis and management of congenital hypothyroidism (CH). A systematic literature search was conducted to identify key articles on neonatal screening, diagnosis, and management of primary and central CH. The evidence-based guidelines were graded with the Grading of Recommendations, Assessment, Development and Evaluation system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion. Summary: The recommendations include the various neonatal screening approaches for CH as well as the etiology (also genetics), diagnostics, treatment, and prognosis of both primary and central CH. When CH is diagnosed, the expert panel recommends the immediate start of correctly dosed levothyroxine treatment and frequent follow-up including laboratory testing to keep thyroid hormone levels in their target ranges, timely assessment of the need to continue treatment, attention for neurodevelopment and neurosensory functions, and, if necessary, consulting other health professionals, and education of the child and family about CH. Harmonization of diagnostics, treatment, and follow-up will optimize patient outcomes. Lastly, all individuals with CH are entitled to a well-planned transition of care from pediatrics to adult medicine. Conclusions: This consensus guidelines update should be used to further optimize detection, diagnosis, treatment, and follow-up of children with all forms of CH in the light of the most recent evidence. It should be helpful in convincing health authorities of the benefits of neonatal screening for CH. Further epidemiological and experimental studies are needed to understand the increased incidence of this condition.

Developmental milestones at one year for the offspring of mothers with congenital hypothyroidism: a population-based study

OBJECTIVE

Maternal thyroid dysfunction during pregnancy is associated with neurodevelopmental impairment in the offspring. No data are currently available for the offspring of patients treated early for congenital hypothyroidism (CH). The aim of this study was to investigate motor and language milestones at one year of age in a population-based registry of children born to young women with CH.

DESIGN AND METHODS

We assessed 110 children born to mothers with CH, and 1367 children from the EDEN French population-based birth cohort study prospectively, at the age of one year, with identical questionnaires. Outcomes were assessed in terms of scores for childhood developmental milestones relating to mobility, motor coordination, communication, motricity and language skills.

RESULTS

After adjustment for confounding factors, children born to mothers with CH were found to have a higher risk of poor motor coordination than those of the EDEN cohort (OR: 4.18, 95% CI: 2.52-6.93). No differences were identified for the other four domains investigated. Children born to mothers with gestational diabetes have a higher risk of low motor coordination score than their peers (OR: 2.10, 95% CI: 1.21-3.66). Children born to mothers with TSH ≥ 10 IU/L during the first six months of pregnancy were more likely to have low motricity or communication skills scores than those born to mothers with lower TSH concentrations (56% vs 21% for each score, P < 0.04).

CONCLUSIONS

Maternal CH may have slight adverse effects on some developmental milestones in the child at one year of age, particularly for children born to mothers with uncontrolled hypothyroidism. However, it remains unclear whether these adverse effects modify subsequent neurodevelopment.

Guidelines for Mass Screening of Congenital Hypothyroidism (2014 revision)

Purpose of developing the guidelines: Mass screening for congenital hypothyroidism started in 1979 in Japan, and the prognosis for intelligence has been improved by early diagnosis and treatment. The incidence was about 1/4000 of the birth population, but it has increased due to diagnosis of subclinical congenital hypothyroidism. The disease requires continuous treatment, and specialized medical facilities should make a differential diagnosis and treat subjects who are positive in mass screening to avoid unnecessary treatment. The Guidelines for Mass Screening of Congenital Hypothyroidism (1998 version) were developed by the Mass Screening Committee of the Japanese Society for Pediatric Endocrinology in 1998. Subsequently, new findings on prognosis and problems in the adult phase have emerged. Based on these new findings, the 1998 guidelines were revised in the current document (hereinafter referred to as the Guidelines). Target disease/conditions: Primary congenital hypothyroidism. Users of the Guidelines: Physician specialists in pediatric endocrinology, pediatric specialists, physicians referring patients to pediatric practitioners, general physicians, laboratory technicians in charge of mass screening, and patients.

Treatment of congenital thyroid dysfunction: Achievements and challenges

The active thyroid hormone tri-iodothyronine (T3) is essential for a normal development of children. Especially within the first years of life, thyroid hormone is pivotal in enabling maturation of complex brain function and somatic growth. The most compelling example for a life without thyroid hormone are those historical cases of children who came to birth without a thyroid gland - as shown in autopsy-studies- and who suffered from untreated hypothyroidism, at that time initially called "sporadic congenital hypothyroidism" (CH). In the last decades huge achievements resulted in a normal development of these children based on newborn screening programs that enable an early onset of a high dose LT4-treatment. Further progress will be necessary to further tailor an individualized thyroid hormone substitution approach and to identify those more complex patients with congenital hypothyroidism and associated defects, who will not benefit from an even optimized LT4 therapy. Besides the primary production of thyroid hormone a variety of further mechanisms are necessary to mediate the function of T3 on normal development that are located downstream of thyroid hormone production. Abnormalities of these mechanisms include the MCT8-transport defect, deiodinase-insufficiency and thyroid hormone receptor alpha-and beta defects. These thyroid hormone resistant diseases can not be treated with classical LT4 substitution alone. The development of new treatment options for those rare cases of thyroid hormone resistance is one of the most challenging tasks in the field of congenital thyroid diseases today.

Pregnancy outcomes and relationship to treatment adequacy in women treated early for congenital hypothyroidism: a longitudinal population-based study

CONTEXT

Untreated hypothyroidism is associated with a higher risk of adverse obstetric and neonatal outcomes. Pregnancy complications have yet to be evaluated in patients treated early for congenital hypothyroidism (CH).

OBJECTIVE

This study aimed to investigate pregnancy outcomes and their determinants in a population-based registry of young adult women with CH.

SETTING AND DESIGN

In total, 1748 subjects were diagnosed with CH in the first 10 years after the introduction of neonatal screening in France; 1158 of these subjects completed a questionnaire on fecundity at a mean age of 25.3 years. We analyzed all declared singleton pregnancies ending after greater than 22 weeks of gestation before the initial survey (n = 207 pregnancies) and in the 3 years following the initial survey (prospective study, n = 174 pregnancies). The reference group comprised 7245 subjects from the French National Perinatal Survey.

MAIN OUTCOME MEASURES

Pregnancy outcomes. Serum TSH concentrations and thyroid hormone requirements.

RESULTS

In both the overall and prospective analyses, CH was associated with gestational hypertension, emergency cesarean delivery, induced labor for vaginal delivery, and prematurity. For the prospective population with CH, the adjusted odds ratios (aOR) (95% confidence interval [CI]) were 2.19 (1.26-3.81), 1.88 (1.17-3.02), 1.58 (1.12-2.24), and 1.85 (1.06-3.25), respectively. TSH concentrations at least 10 mIU/l during the first 3 or 6 months of pregnancy were associated with a higher risk of preterm delivery (aOR, 5.6; 95% CI, 1.6-20.0) and fetal macrosomia (aOR, 4.5; 95% CI, 1.03-20.1), respectively, whereas no such relationship was observed for TSH concentrations of 5.0-9.9 mIU/l.

CONCLUSION

CH may result in adverse pregnancy outcomes. These nationwide data suggest that better thyroid disease management is required, particularly during the first two trimesters of pregnancy, together with vigilant monitoring.

Congenital hypothyroidism: a clinical update of long-term outcome in young adults

Congenital hypothyroidism (CH) is the most common congenital endocrine disorder. The early treatment of CH patients has successfully improved the prognosis and management of this disorder. Optimal treatment and management throughout the patient's life, beginning in the neonatal period, are required to ensure long-term health. Affected patients should be offered assessments of associated medical conditions and provided with accurate information about their condition throughout their lives, but particularly during the transition from pediatric to adult services. This review provides a summary of current knowledge about the long-term outcomes of these patients and appropriate management into early adulthood. We carried out a systematic search of the Medline database to identify relevant articles. Despite major improvements in prognosis, the impact of CH is clearly not uniform, and management should take into account a broader range of relevant indicators, including CH severity, associated comorbid conditions and the adequacy of treatment during childhood and adulthood. The early diagnosis and management of associated medical conditions, and better educational strategies to improve compliance with treatment, should improve the long-term prognosis. Further studies are required to explore changes with aging.

European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).

EVIDENCE

A systematic literature search was conducted to identify key articles relating to the screening, diagnosis, and management of CH. The evidence-based guidelines were developed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion.

CONSENSUS PROCESS

Thirty-two participants drawn from the European Society for Paediatric Endocrinology and five other major scientific societies in the field of pediatric endocrinology were allocated to working groups with assigned topics and specific questions. Each group searched the literature, evaluated the evidence, and developed a draft document. These papers were debated and finalized by each group before presentation to the full assembly for further discussion and agreement.

RECOMMENDATIONS

The recommendations include: worldwide neonatal screening, approaches to assess the cause (including genotyping) and the severity of the disorder, the immediate initiation of appropriate L-T4 supplementation and frequent monitoring to ensure dose adjustments to keep thyroid hormone levels in the target ranges, a trial of treatment in patients suspected of transient CH, regular assessments of developmental and neurosensory functions, consulting health professionals as appropriate, and education about CH. The harmonization of diagnosis, management, and routine health surveillance would not only optimize patient outcomes, but should also facilitate epidemiological studies of the disorder. Individuals with CH require monitoring throughout their lives, particularly during early childhood and pregnancy.

European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).

EVIDENCE

A systematic literature search was conducted to identify key articles relating to the screening, diagnosis, and management of CH. The evidence-based guidelines were developed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion.

CONSENSUS PROCESS

Thirty-two participants drawn from the European Society for Paediatric Endocrinology and five other major scientific societies in the field of pediatric endocrinology were allocated to working groups with assigned topics and specific questions. Each group searched the literature, evaluated the evidence, and developed a draft document. These papers were debated and finalized by each group before presentation to the full assembly for further discussion and agreement.

RECOMMENDATIONS

The recommendations include: worldwide neonatal screening, approaches to assess the cause (including genotyping) and the severity of the disorder, the immediate initiation of appropriate L-T4 supplementation and frequent monitoring to ensure dose adjustments to keep thyroid hormone levels in the target ranges, a trial of treatment in patients suspected of transient CH, regular assessments of developmental and neurosensory functions, consulting health professionals as appropriate, and education about CH. The harmonization of diagnosis, management, and routine health surveillance would not only optimize patient outcomes, but should also facilitate epidemiological studies of the disorder. Individuals with CH require monitoring throughout their lives, particularly during early childhood and pregnancy.