Maternal Thyroid Function in Early Pregnancy and Child Neurodevelopmental Disorders: A Danish Nationwide Case-Cohort Study

Congenital hypothyroidism and risk of subsequent autism spectrum disorder and attention-deficit/hyperactivity disorder in Taiwan

AIM

Evidence suggests an association between maternal hypothyroidism and risk of attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD) in offspring. We examined the risk of ASD and ADHD in individuals with congenital hypothyroidism (CHT).

METHODS

A nationwide population-based cohort study enrolled a total of 1260 children younger than 12 years with a confirmed diagnosis of CHT and no prior diagnosis of any neurodevelopmental disorders, selected from the National Health Insurance Research Database of Taiwan between 1998 to 2013. In addition, 12,600 controls matched for sex, age, and residence were selected. Cox proportional hazards analysis was used to investigate the association among CHT, ASD, and ADHD.

RESULTS

Children with CHT were associated with a higher incidence of ASD (7.1‰ vs 1.3‰, P < 0.001) and ADHD (39.7‰ vs 18.7‰, P < 0.001) than the control group. Cox regression analyses demonstrated that children with CHT were associated with elevated risks of ASD (hazard ratio [HR], 4.72 [95% confidence interval (CI), 2.08-10.70]) and ADHD (HR, 2.03 [95% CI, 1.49-2.77]), after adjusting for demographic data and family history of major psychiatric disorders, compared with the control group.

CONCLUSION

Children with CHT were associated with approximately a two-fold increased risk of ADHD and a four-fold increased risk of ASD than the control group. Our study highlights the need for future research to elucidate the potential pathophysiology among CHD, ASD, and ADHD.

Advances in serum thyroid hormone levels and seizures

Epilepsy, a common neurological disorder, is characterized by paroxysmal, short-term, repetitive, and stereotypical features, significantly impacting patients' quality of life. Currently, the pathogenesis of epilepsy remains incompletely understood. Changes in neuronal excitability, imbalances in glutamate and gamma-aminobutyric acid (GABA) levels, alterations in the activity of GABA receptors, and dysfunction of GABA receptors are considered closely related to its occurrence. Thyroid hormones, vital for human growth and development, also play a crucial role in the nervous system. They mediate oxidative stress, influence reactive oxygen species production, affect mitochondrial function and neuronal excitability, and modulate glutamate and GABA levels. Also, they combine with thyroid hormone receptors and exert genomic effects by regulating the expression of numerous genes. However, once there are defects in thyroid hormone signaling, these defects may lead to severe neurodevelopmental disorders that are associated with an increased frequency of seizures. The impact of antiseizure medications (ASMs) on serum thyroid hormone levels, particularly traditional ASMs, has been extensively studied. It is reported that conventional ASMs such as phenobarbital, phenytoin sodium, carbamazepine, and valproate sodium were more likely to induce subclinical hypothyroidism (elevated TSH with normal FT4) or isolated hypothyroidism (decreased FT4 with normal TSH). However, the new ASMs, such as levetiracetam, have no effect on thyroid hormone levels. Together, seizures not only affect thyroid hormone levels, but abnormal thyroid hormone levels can also influence seizures. However, the precise mechanism underlying the interaction between serum thyroid hormone levels and seizures remains unclear. This review aims to explore the relationship between thyroid hormone levels and seizures, along with the underlying mechanisms.

Convergence on CaMK4: A Key Modulator of Autism-Associated Signaling Pathways in Neurons

Although the precise underlying cause(s) of autism spectrum disorder remain unclear, more than 1000 rare genetic variations are associated with the condition. For many people living with profound autism, this genetic heterogeneity has impeded the identification of common biological targets for therapy development for core and comorbid traits that include significant impairments in social communication and repetitive and restricted behaviors. A substantial number of genes associated with autism encode proteins involved in signal transduction and synaptic transmission that are critical for brain development and function. CAMK4 is an emerging risk gene for autism spectrum disorder that encodes the CaMK4 (calcium/calmodulin-dependent protein kinase 4) enzyme. CaMK4 is a key component of a Ca2+-activated signaling pathway that regulates neurodevelopment and synaptic plasticity. In this review, we discuss 3 genetic variants of CAMK4 found in individuals with hyperkinetic movement disorder and comorbid neurological symptoms including autism spectrum disorder that are likely pathogenic with monogenic effect. We also comment on 4 other genetic variations in CAMK4 that show associations with autism spectrum disorder, as well as 12 examples of autism-associated variations in other genes that impact CaMK4 signaling pathways. Finally, we highlight 3 environmental risk factors that impact CaMK4 signaling based on studies of preclinical models of autism and/or clinical cohorts. Overall, we review molecular, genetic, physiological, and environmental evidence that suggest that defects in the CaMK4 signaling pathway may play an important role in a common autism pathogenesis network across numerous patient groups, and we propose CaMK4 as a potential therapeutic target.

Malpresentation and autism spectrum disorder in the study to explore early development

BACKGROUND

An infant's presentation at delivery may be an early indicator of developmental differences. Non-vertex presentation (malpresentation) complicates delivery and often leads to caesarean section, which has been associated with neurodevelopmental delays, including autism spectrum disorder (ASD). However, malpresentation could be an early sign of an existing developmental problem that is also an upstream factor from caesarean delivery. Little research has been done to investigate the association between malpresentation and ASD.

OBJECTIVES

We examine the association between malpresentation at delivery and ASD and whether this association differs by gestational age.

METHODS

We used data from the Study to Explore Early Development (SEED), a multi-site, case-control study of children with ASD compared to population controls. The foetal presentation was determined using medical records, birth records and maternal interviews. We defined malpresentation as a non-vertex presentation at delivery, then further categorised into breech and other malpresentation. We used multivariable logistic regression to estimate the adjusted odds ratio (aOR) for the association between malpresentation and ASD.

RESULTS

We included 4047 SEED participants, 1873 children with ASD and 2174 controls. At delivery, most infants presented vertex (n = 3760, 92.9%). Malpresentation was associated with higher odds of ASD (aOR 1.31, 95% confidence interval [CI] 1.02, 1.68) after adjustment for maternal age, poverty level, hypertensive disorder and smoking. The association was similar for breech and other types of malpresentation (aOR 1.28, 95% CI 0.97, 1.70 and aOR 1.40, 95% CI 0.87, 2.26, respectively) and did not differ markedly by gestational age.

CONCLUSIONS

Malpresentation at delivery was modestly associated with ASD. Early monitoring of the neurodevelopment of children born with malpresentation could identify children with ASD sooner and enhance opportunities to provide support to optimise developmental outcomes.

The generation gap in endocrine disruption: Can the integrated fish endocrine disruptor test (iFEDT) bridge the gap by assessing intergenerational effects of thyroid hormone system disruption?

Thyroid hormones (THs) act early in ontogenesis, even prior to the differentiation of thyrocytes. Maternal transfer of THs is therefore known to play an essential role in early development. Current OECD test guidelines for the assessment of TH system disruption (THSD) do not address inter- or transgenerational effects. The integrated fish endocrine disruptor test (iFEDT), a test combining parental and developmental exposure of filial fish, may fill this gap. We tested the ability of the iFEDT to detect intergenerational effects in zebrafish (Danio rerio): Parental fish were exposed to propylthiouracil (PTU), an inhibitor of TH synthesis, or not exposed. The offspring was submitted to a crossed experimental design to obtain four exposure scenarios: (1) no exposure at all, (2) parental exposure only, (3) embryonic exposure only, and (4) combined parental and embryonic exposure. Swim bladder inflation, visual motor response (VMR) and gene expression of the progeny were analysed. Parental, but not embryonic PTU exposure reduced the size of the swim bladder of 5 d old embryos, indicating the existence of intergenerational effects. The VMR test produced opposite responses in 4.5 d old embryos exposed to PTU vs. embryos derived from exposed parents. Embryonic exposure, but not parental exposure increased gene expression of thyroperoxidase, the target of PTU, most likely due to a compensatory mechanism. The gene expression of pde-6h (phosphodiesterase) was reduced by embryonic, but not parental exposure, suggesting downregulation of phototransduction pathways. Hence, adverse effects on swim bladder inflation appear more sensitive to parental than embryonic exposure and the iFEDT represents an improvement in the testing strategy for THSD.

The Potential Role of Thyroid Hormone Therapy in Neural Progenitor Cell Differentiation and Its Impact on Neurodevelopmental Disorders

Thyroid hormone (T3) plays a vital role in brain development and its dysregulation can impact behavior, nervous system function, and cognitive development. Large case-cohort studies have associated abnormal maternal T3 during early pregnancy to epilepsy, autism, and attention deficit hyperactivity disorder (ADHD) in children. Recent experimental findings have also shown T3's influence on the fate of neural precursor cells and raise the question of its convergence with embryonic neural progenitors. Our objective was to investigate how T3 treatment affects neuronal development and functionality at the cellular level. In vitro experiments using neural precursor cells (NPCs) measured cell growth and numbers after exposure to varying T3 concentrations. Time points included week 0 (W0) representing NPCs treated with 100 nM T3 for 5 days, and differentiated cortical neurons assessed at weeks 3 (W3), 6 (W6), and 8 (W8). Techniques such as single-cell calcium imaging and whole-cell patch clamp were utilized to evaluate neuronal activity and function. IHC staining detected mature neuron markers, and RNA sequencing enabled molecular profiling. W6 and W8 neurons exhibited higher action potential frequencies, with W6 showing increased peak amplitudes and shortened inter-spike intervals by 50%, indicating enhanced activity. Transcriptomic analysis revealed that W6 T3-treated neurons formed a distinct cluster, suggesting accelerated maturation. Comparison with the whole transcriptome further unveiled a correlation between W6 neurons treated with T3 and neuronal regulatory elements associated with autism and ADHD. These findings provide insights into T3's impact on neuronal development and potential mechanisms of T3 dysregulation and neurodevelopmental disorders.

Gestational hypothyroxinemia induces ASD-like phenotypes in behavior, proinflammatory markers, and glutamatergic protein expression in mouse offspring of both sexes

Background

The prevalence of autism spectrum disorder (ASD) has significantly risen in the past three decades, prompting researchers to explore the potential contributions of environmental factors during pregnancy to ASD development. One such factor of interest is gestational hypothyroxinemia (HTX), a frequent condition in pregnancy associated with cognitive impairments in the offspring. While retrospective human studies have linked gestational HTX to autistic traits, the cellular and molecular mechanisms underlying the development of ASD-like phenotypes remain poorly understood. This study used a mouse model of gestational HTX to evaluate ASD-like phenotypes in the offspring.

Methods

To induce gestational HTX, pregnant mice were treated with 2-mercapto-1-methylimidazole (MMI), a thyroid hormones synthesis inhibitor, in the tap-drinking water from embryonic days (E) 10 to E14. A separate group received MMI along with a daily subcutaneous injection of T4, while the control group received regular tap water during the entire pregnancy. Female and male offspring underwent assessments for repetitive, anxious, and social behaviors from postnatal day (P) 55 to P64. On P65, mice were euthanized for the evaluation of ASD-related inflammatory markers in blood, spleen, and specific brain regions. Additionally, the expression of glutamatergic proteins (NLGN3 and HOMER1) was analyzed in the prefrontal cortex and hippocampus.

Results

The HTX-offspring exhibited anxious-like behavior, a subordinate state, and impaired social interactions. Subsequently, both female and male HTX-offspring displayed elevated proinflammatory cytokines in blood, including IL-1β, IL-6, IL-17A, and TNF-α, while only males showed reduced levels of IL-10. The spleen of HTX-offspring of both sexes showed increased Th17/Treg ratio and M1-like macrophages. In the prefrontal cortex and hippocampus of male HTX-offspring, elevated levels of IL-17A and reduced IL-10 were observed, accompanied by increased expression of hippocampal NLGN3 and HOMER1. All these observations were compared to those observed in the Control-offspring. Notably, the supplementation with T4 during the MMI treatment prevents the development of the observed phenotypes. Correlation analysis revealed an association between maternal T4 levels and specific ASD-like outcomes.

Discussion

This study validates human observations, demonstrating for the first time that gestational HTX induces ASD-like phenotypes in the offspring, highlighting the need of monitoring thyroid function during pregnancy.

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

Gestational thyroid hormones and autism-related traits in the EARLI and HOME studies

Thyroid hormones are essential for neurodevelopment. Few studies have considered associations with quantitatively measured autism spectrum disorder (ASD)-related traits, which may help elucidate associations for a broader population. Participants were drawn from two prospective pregnancy cohorts: the Early Autism Risk Longitudinal Investigation (EARLI), enrolling pregnant women who already had a child with ASD, and the Health Outcomes and Measures of the Environment (HOME) Study, following pregnant women from the greater Cincinnati, OH area. Gestational thyroid-stimulating hormone (TSH) and free thyroxine (FT4) were measured in mid-pregnancy 16 (±3) weeks gestation serum samples. ASD-related traits were measured using the Social Responsiveness Scale (SRS) at ages 3-8 years. The association was examined using quantile regression, adjusting for maternal and sociodemographic factors. 278 participants (132 from EARLI, 146 from HOME) were included. TSH distributions were similar across cohorts, while FT4 levels were higher in EARLI compared to HOME. In pooled analyses, particularly for those in the highest SRS quantile (95th percentile), higher FT4 levels were associated with increasing SRS scores (β = 5.21, 95% CI = 0.93, 9.48), and higher TSH levels were associated with decreasing SRS scores (β = -6.94, 95% CI = -11.04, -2.83). The association between TSH and SRS remained significant in HOME for the 95% percentile of SRS scores (β = -6.48, 95% CI = -12.16, -0.80), but not EARLI. Results for FT4 were attenuated when examined in the individual cohorts. Our results add to evidence that gestational thyroid hormones may be associated with ASD-related outcomes by suggesting that relationships may differ across the distribution of ASD-related traits and by familial likelihood of ASD.

Hormonal Changes in Women with Epilepsy

Epilepsy is a prevalent neurological disorder among women globally, often requiring long-term treatment. Hormonal fluctuations in women with epilepsy (WWE) can have reciprocal effects on epilepsy and antiseizure medications (ASMs), posing significant challenges for WWE. Notably, WWE commonly experience endocrine alterations such as thyroid dysfunctions, low bone metabolism, and reproductive hormone irregularities. On the one hand, the presence of hormones in women with epilepsy affects their susceptibility to epilepsy as well as the metabolism of antiseizure medications in various ways. On the other hand, epilepsy itself and the use of antiseizure medications impact the production, secretion, and metabolism of hormones, resulting in low fertility, increased risk of pregnancy complications, negative offspring outcomes, and so on. In order to develop more precise treatment strategies in the future, it is necessary to comprehend the explicit relationships between hormones, epilepsy, and antiseizure medications, as well as to elucidate the currently known mechanisms underlying these interactions.

Maternal Thyroid Dysfunction During Pregnancy as an Etiologic Factor in Autism Spectrum Disorder: Challenges and Opportunities for Research

Background: Autism spectrum disorder (ASD) is a neurodevelopmental condition with unknown etiology. Both genetic and environmental factors have been associated with ASD. Environmental exposures during the prenatal period may play an important role in ASD development. This narrative review critically examines the evidence for a relationship between maternal thyroid dysfunction during pregnancy and ASD in the child. Summary: Studies that assessed the associations of hypothyroidism, hyperthyroidism, hypothyroxinemia, thyroid hormone concentrations, or autoimmune thyroid disease with ASD outcomes were included. Most research focused on the relationship between hypothyroidism and ASD. Multiple population-based studies found that maternal hypothyroidism was associated with higher likelihood of an ASD diagnosis in offspring. Associations with other forms of maternal thyroid dysfunction were less consistent. Findings may have been affected by misclassification bias, survival bias, or publication bias. Studies using medical records may have misclassified subclinical thyroid dysfunction as euthyroidism. Two studies that assessed children at early ages may have misclassified those with ASD as typically developing. Most studies adjusted for maternal body mass index (BMI) and/or mental illness, but not interpregnancy interval or pesticide exposure, all factors associated with fetal survival and ASD. Most studies reported a combination of null and statistically significant findings, although publication bias is still possible. Conclusions: Overall, evidence supported a positive association between maternal thyroid dysfunction during pregnancy and ASD outcomes in the child, especially for hypothyroidism. Future studies could reduce misclassification bias by using laboratory measures instead of medical records to ascertain thyroid dysfunction and evaluating children for ASD at an age when it can be reliably detected. Survival bias could be further mitigated by adjusting models for more factors associated with fetal survival and ASD. Additional research is needed to comprehensively understand the roles of maternal levothyroxine treatment, iodine deficiency, or exposure to thyroid-disrupting compounds in the relationship between maternal thyroid dysfunction and child ASD outcomes.

A co-twin control study of in utero exposure to poly- and perfluoroalkyl substances and associations with neonatal thyroid-stimulating hormone

Research quantifying associations between early-life exposure to poly- and perfluoroalkyl substances (PFAS) and neonatal thyroid hormone levels is limited and reports inconsistent results. This study aimed to examine the associations of in utero PFAS exposure with neonatal thyroid-stimulating hormone (TSH), and to verify whether genetic and familial factors contribute to these associations. Within Wuhan Twin Birth Cohort study, we included 148 mother-twin pairs recruited between March 2016 and January 2018. Maternal plasma PFAS concentrations were measured at three different trimesters and averaged. Additionally, we measured cord plasma PFAS concentrations for twin newborns and retrieved their TSH levels from the medical system. Multivariable linear regression, generalized estimation equation, and linear mixed models were used to examine the covariate-adjusted associations. For maternal PFAS analyses, a 2-fold increment of average maternal perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) concentrations was linked with a 15% (95% CI: 2.5%, 28%) and 14% (95% CI: 2.4%, 28%) increase in neonatal TSH, respectively. For twin newborns discordant for PFAS exposure, a 2-fold increment of cord plasma PFOA, PFDA, perfluoroundecanoic acid (PFUdA), and perfluorohexanesulfonic acid (PFHxS) concentrations was related to a 7.1% (95% CI: 0.31%, 14%), 12% (95% CI: 4.8%, 20%), 7.5% (95% CI: 0.30%, 15%), and 8.5% (95% CI: 3.0%, 14%) increase in TSH among twins as individuals, respectively. Although these associations were mainly observed between twin pairs, certain PFAS exposure might have an independent association with increased TSH. Our present study suggests that higher maternal and cord plasma PFAS concentrations are associated with increased neonatal TSH, and genetic and familial factors contribute to these associations.

Levothyroxine Treatment Among Pregnant Women and Risk of Seizure in Children: A Population-Based Cohort Study

INTRODUCTION AND OBJECTIVE

The risk of seizure in offspring following prenatal exposure to levothyroxine is not well investigated. This study aimed to evaluate the association between levothyroxine treatment among pregnant women and the risk of seizure in their offspring.

METHODS

This population-based cohort study included all pregnant women who delivered a live birth between January 2001 to January 2018, with a follow-up to December 2020, using data from the Hong Kong Clinical Data Analysis and Reporting System. Propensity score fine-stratification weighted hazard ratios (wHR) with 95% confidence intervals (CIs) were presented to assess the association between maternal levothyroxine use during pregnancy and seizures in children.

RESULTS

Among 528,343 included mother-child pairs, 3044 children were prenatally exposed to levothyroxine at any time during the pregnancy period. A significantly increased risk of seizure was observed in children of the prenatally exposed group compared with the prenatally unexposed group (wHR 1.12, 95% CI 1.02-1.22). An increased risk of seizure was observed when comparing the prenatally exposed group with euthyroid mothers who had no history of thyroid-related diagnosis or prescriptions (wHR 1.12, 95% CI 1.02-1.23). However, no significant difference was observed between the prenatally exposed group and those previously exposed to levothyroxine but had stopped during pregnancy (wHR 0.97, 95% CI 0.66-1.44). No significant difference was observed in the sibling-matched analysis either (wHR 1.23, 95% CI 0.76-2.01).

CONCLUSION

The observed increased risk of seizure in children born from mothers exposed to levothyroxine during pregnancy might be due to residual confounding by maternal thyroid disease. The findings support the current guidelines on the safe use of levothyroxine treatment during pregnancy.

Maternal thyroid hormone receptor β activation in mice sparks brown fat thermogenesis in the offspring

It is well established that maternal thyroid hormones play an important role for the developing fetus; however, the consequences of maternal hyperthyroidism for the offspring remain poorly understood. Here we show in mice that maternal 3,3',5-triiodothyronine (T3) treatment during pregnancy leads to improved glucose tolerance in the adult male offspring and hyperactivity of brown adipose tissue (BAT) thermogenesis in both sexes starting early after birth. The activated BAT provides advantages upon cold exposure, reducing the strain on other thermogenic organs like muscle. This maternal BAT programming requires intact maternal thyroid hormone receptor β (TRβ) signaling, as offspring of mothers lacking this receptor display the opposite phenotype. On the molecular level, we identify distinct T3 induced alterations in maternal serum metabolites, including choline, a key metabolite for healthy pregnancy. Taken together, our results connect maternal TRβ activation to the fetal programming of a thermoregulatory phenotype in the offspring.

Assisted Reproductive Technology and Disease Management in Infertile Women with Multiple Sclerosis

Multiple sclerosis (MS) predominantly affects women of fertile age. Various aspects of MS could impact on fertility, such as sexual dysfunction, endocrine alterations, autoimmune imbalances, and disease-modifying therapies (DMTs). The proportion of women with MS (wMS) requesting infertility management and assisted reproductive technology (ART) is increasing over time. In this review, we report on data regarding ART in wMS and address safety issues. We also discuss the clinical aspects to consider when planning a course of treatment for infertility, and provide updated recommendations to guide neurologists in the management of wMS undergoing ART, with the goal of reducing the risk of disease activation after this procedure. According to most studies, there is an increase in relapse rate and magnetic resonance imaging activity after ART. Therefore, to reduce the risk of relapse, ART should be considered in wMS with stable disease. In wMS, especially those with high disease activity, fertility issues should be discussed early as the choice of DMT, and fertility preservation strategies might be proposed in selected cases to ensure both disease control and a safe pregnancy. For patients with stable disease taking DMTs compatible with pregnancy, treatment should not be interrupted before ART. If the ongoing therapy is contraindicated in pregnancy, then it should be switched to a compatible therapy. Prior to beginning fertility treatments in wMS, it would be reasonable to assess vitamin D serum levels, thyroid function and its antibody serum levels; start folic acid supplementation; and ensure smoking and alcohol cessation, adequate sleep, and food hygiene. Cervico-vaginal swabs for Ureaplasma urealyticum, Mycoplasma hominis, and Chlamydia trachomatis, as well as serology for viral hepatitis, HIV, syphilis, and cytomegalovirus, should be performed. Steroids could be administered under specific indications. Although the available data do not clearly show a definite raised relapse risk associated with a specific ART protocol, it seems reasonably safe to prefer the use of gonadotropin-releasing hormone (GnRH) antagonists for ovarian stimulation. Close clinical and radiological monitoring is reasonably recommended, particularly after hormonal stimulation and in case of pregnancy failure.

Interaction between isolated maternal hypothyroxinemia and pregnancy-related anxiety on preschooler's internalizing and externalizing problems: A birth cohort study

BACKGROUND

Isolated maternal hypothyroxinemia (IMH) and pregnancy-related anxiety may increase the risk of offspring's emotional and behavioral problems, but little is known about their potential interactive effect on preschoolers' internalizing and externalizing problems.

METHODS

We conducted a large prospective cohort study in Ma'anshan Maternal and Child Health Hospital between May 2013 and September 2014. There were a total of 1372 mother-child pairs from the Ma'anshan birth cohort (MABC) included in this study. IMH was defined as the thyroid-stimulating hormone (TSH) level within the normal reference range (2.5-97.5th percentile) and the free thyroxine (FT₄) level below the 2.5th percentile, and negative TPOAb. The pregnancy-related anxiety questionnaire (PRAQ) was used to assess women's pregnancy-related anxiety status in the first (1-13 weeks), second (14-27 weeks) and third (after 28 weeks) trimesters of pregnancy. The Achenbach Child Behavior Checklist (CBCL/1.5-5) was used to assess preschoolers' internalizing and externalizing problems.

RESULTS

Preschoolers born of mothers with IMH and anxiety had an increased risk of anxious/depressed (OR = 6.40, 95% CI 1.89-21.68), somatic complaints (OR = 2.69, 95% CI 1.01-7.20), attention problems (OR = 2.95, 95% CI 1.00-8.69) and total problems (OR = 3.40, 95% CI 1.60-7.21). Particularly, mothers with IMH and anxiety was associated with an increased risk of preschool girls' anxious/depressed (OR = 8.14, 95% CI 1.74-38.08), withdrawn (OR = 7.03, 95% CI 2.25-21.92), internalizing problems (OR = 2.66, 95% CI 1.00-7.08), and total problems (OR = 5.50, 95% CI 2.00-15.10).

CONCLUSIONS

IMH and pregnancy-related anxiety during pregnancy may synergistically increase the risk of internalizing and externalizing problems in preschooler children. This interaction is distinct in internalizing problems of preschool girls.

Recommendations of the AGG (Working Group for Obstetrics, Department of Maternal Diseases) on How to Treat Thyroid Function Disorders in Pregnancy

Objective These recommendations from the AGG (Committee for Obstetrics, Department of Maternal Diseases) on how to treat thyroid function disorder during pregnancy aim to improve the diagnosis and management of thyroid anomalies during pregnancy.

Methods Based on the current literature, the task force members have developed the following recommendations and statements. These recommendations were adopted after a consensus by the members of the working group.

Recommendations The following manuscript gives an insight into physiological and pathophysiological thyroid changes during pregnancy, recommendations for clinical and subclinical hypo- and hyperthyroidism, as well as fetal and neonatal diagnostic and management strategies.

Serum TSH Levels are Associated with Hyperactivity Behaviors in Children with Attention Deficit/Hyperactivity Disorder

Objective

Previous studies indicated that maternal thyroid dysfunction increase the offspring's risk for attention deficit/hyperactivity disorder (ADHD). However, the relationship between thyroid function and symptoms in children with ADHD remains unclear.

Methods

A total of 49 children with ADHD were enrolled. The Conners 3 scale was used to estimate the symptoms associated with ADHD. Correlation between thyroid hormones and the scores of the Conners 3 scale was evaluated by Pearson correlation analysis. Then, ADHD children were divided into two groups according to the hyperactivity index (HI) of the Conners 3 scale: ADHD children with hyperactivity behaviors (HB) (HI > 1.5) and ADHD children without HB (HI < 1.5). The demographic characteristics, thyroid hormones, and routine laboratory parameters between the two groups were collected. To distinguish HI-related factors, a univariate analysis and a binary logistic regression predictive model were used. The discriminative ability of thyroid stimulating hormone (TSH) in predicting ADHD children with HB from ADHD children without HB was investigated using the receiver operating characteristic (ROC) curve method.

Results

The levels of TSH were positively correlated to the scores of the Conners 3 scale (r = 0.338, P = 0.033) and HI (r = 0.371, P = 0.019). Moreover, the levels of TSH, serum ferritin, and lactic acid were significantly increased in ADHD children with HB compared to ADHD children without HB (all P < 0.05). Furthermore, the results of binary logistic regression found that TSH (OR 2.243 (CL 1.052-4.783)) and lactic acid (OR 1.018 (CI 1.003-1.032)) were independently associated with HI. Additionally, ROC analysis indicated the potential diagnostic value of TSH in discriminating ADHD children with HB from ADHD children without HB with an AUC of 0.684.

Conclusion

These results suggested that the serum TSH levels may be related to the HB in children with ADHD.

A Bayesian model to estimate the cutoff value of TSH for management of preterm birth

BACKGROUND

Determining a thyroid hormone cutoff value in pregnancy is challenging issue and several approaches have been introduced to optimize a utility function. We aimed to estimate the cutoff value of TSH using Bayesian method for prediction of preterm-birth.

METHODS

This study was a secondary-analysis of the population-based data collected prospectively within the framework of the Tehran Thyroid and Pregnancy Study. A total of 1,538 pregnant women attending prenatal clinics.

RESULTS

Using Bayesian method resulted a TSH-cutoff of (3.97mIU/L,95%CI:3.95-4.00) for distinguishing pregnant women at risk of preterm-birth. The cutoff was associated with acceptable positive predictive and negative predictive values (0.84,95% CI:0.80-0.88) and 0.92 (95%CI: 0.91-0.94), respectively). In women who were negative for thyroid peroxides antibody (TPOAb) with sufficient urinary iodine concentration (UIC), the TSH cutoff of 3.92 mIU/L(95%CI:3.70-4) had the highest predictive value; whereas in TPOAb positive women with insufficient UIC, the cutoff of 4.0 mIU/L(95%:CI 3.94-4) could better predict preterm birth. Cutoffs estimated in this study are close to the revised TSH value of 4.0mIU/L which is currently recommended by the American Thyroid Association.

CONCLUSION

Regardless of TPOAb status or iodine insufficiency, risk of preterm labor is increased in pregnant women with TSH value of > 3.92 mIU/L; these women may benefit from Levothyroxine (LT4) therapy for preventing preterm birth.

Schmidt R, N. Pearce E. Prenatal Exposure to Per- and Polyfluoroalkyl Substances, Maternal Thyroid Dysfunction, and Child Autism Spectrum Disorder

Autism spectrum disorder (ASD), with its high economic and societal costs, is a growing public health concern whose prevalence has risen steadily over the last two decades. Although actual increased incidence versus improved diagnosis remains controversial, the increased prevalence of ASD suggests non-inherited factors as likely contributors. There is increasing epidemiologic evidence that abnormal maternal thyroid function during pregnancy is associated with increased risk of child ASD and other neurodevelopmental disorders. Prenatal exposure to endocrine-disrupting chemicals such as per- and polyfluoroalkyl substances (PFAS) is known to disrupt thyroid function and can affect early brain development; thus, thyroid dysfunction is hypothesized to mediate this relationship. The concept of a potential pathway from prenatal PFAS exposure through thyroid dysfunction to ASD etiology is not new; however, the extant literature on this topic is scant. The aim of this review is to evaluate and summarize reports with regard to potential mechanisms in this pathway.

Association of maternal levothyroxine use during pregnancy with offspring birth and neurodevelopmental outcomes: a population-based cohort study

BACKGROUND

The influence of maternal levothyroxine treatment during pregnancy remains unclear. This study aimed to evaluate the associations of maternal levothyroxine treatment during pregnancy with the birth and neurodevelopmental outcomes in offspring.

METHODS

This population-based cohort study was conducted among pregnant women using the Hong Kong Clinical Data Analysis and Reporting System. Mother-child pairs in Hong Kong from 2001 to 2015 were included and children were followed up till 2020. We defined the exposure group as mothers who were exposed to levothyroxine during pregnancy. Preterm birth and small for gestational age (SGA) were included as birth outcomes. Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) were included as neurodevelopmental outcomes. Odds ratios (OR) or hazard ratios (HRs) with a 95% confidence interval (CI) were evaluated to assess the association of gestational levothyroxine use with offspring birth and neurodevelopmental outcomes respectively, using propensity score fine-stratification weighting and a Cox proportional hazards regression model.

RESULTS

Among 422,156 mother-child pairs, 2125 children were born from mothers exposed to levothyroxine during pregnancy. A significantly increased risk of preterm birth was observed in children with maternal levothyroxine exposure during pregnancy, when compared to mothers who had no history of thyroid-related diagnoses or prescriptions (weighted OR [wOR]: 1.22, 95% CI: 1.07, 1.39). Similarly, an increased risk of preterm birth was found among children of gestational levothyroxine users, when compared to children of mothers who had used levothyroxine before but stopped during pregnancy (wOR: 2.16, 95% CI: 1.09, 4.25). Sensitivity analysis, by excluding mothers exposed to psychotropic or antiepileptic medications before or during pregnancy, also indicated a similar increased risk of preterm birth regarding the gestational use of levothyroxine (wOR: 1.26, 95% CI: 1.10, 1.45). No significant association was observed for the risk of SGA, ADHD, and ASD.

CONCLUSIONS

There is no evidence that gestational use of levothyroxine is associated with SGA, ADHD, or ASD in offspring. Gestational levothyroxine treatment is associated with a higher risk of preterm birth. Such risk might be confounded by the underlying maternal thyroid disease itself, however, we cannot completely exclude the possible effect of gestational L-T4 treatment on offspring preterm birth. Our findings provided support to the current guidelines on the cautious use of levothyroxine treatment during pregnancy.

Late offspring effects of antenatal thyroid screening

BACKGROUND

Thyroid dysfunction in pregnancy is associated with adverse offspring outcomes and recent birth-cohort studies suggest that even mild degrees of thyroid dysfunction may be linked with a range of late cognitive and behavioural effects in childhood and adolescence.

SOURCES OF DATA

This review summarizes recent literature of observational studies and critically appraises randomized controlled trials (RCTs) of antenatal thyroid screening and Levothyroxine intervention.

AREAS OF AGREEMENT

Overt hypothyroidism and hyperthyroidism carry significant risks for unfavourable offspring outcomes and should be appropriately corrected in pregnancy.

AREAS OF CONTROVERSY

The significance of subclinical hypothyroidism and hypothyroxinaemia is still unclear. Meta-analyses of birth-cohort studies show associations of maternal subclinical hypothyroidism and hypothyroxinaemia with intellectual deficits, attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders, while hyperthyroidism and high-normal FT4 were linked with ADHD. RCTs have shown no benefits of screening on neurodevelopmental outcomes although Levothyroxine could have been initiated too late in pregnancy in these trials.

GROWING POINTS

A small number of studies have shown inconsistent associations of maternal thyroid dysfunction with offspring cardiometabolic indices including blood pressure and body weight. Correction of maternal thyroid dysfunction was, however, associated with favourable long-term metabolic profiles in mothers, including lipid profiles, fat mass and body mass index. Antenatal thyroid screening may therefore present opportunities for optimizing a wider range of outcomes than envisaged.

AREAS FOR DEVELOPING RESEARCH

Future trials with early antenatal thyroid screening and intervention are necessary to clarify the impact of screening on late offspring and maternal effects.

Maternal Thyroid Function and Birth Weight in Twins

CONTEXT

Thyroid hormones are associated with birth weight in singleton pregnancy. Twin pregnancies need more thyroid hormones to maintain the normal growth and development of the fetuses compared with single pregnancy.

OBJECTIVE

We aimed to investigate the association of thyroid hormones and birth weight in twins.

METHODS

This was a retrospective cohort study in a Chinese population. Pregnant women who received regular antenatal health care and delivered live-born twins from 2014 to 2019 were included (n = 1626). Linear mixed model with restricted cubic splines and logistic regression models were used to estimate the association of thyroid hormones with birth weight and birth weight discordance in twins.

RESULTS

We observed that both thyrotropin (TSH) and free thyroxine (FT4) were not associated with birth weight in twins overall, while when stratifying on fetal sex or chorionicity, there were nonlinear association between FT4 levels and birth weight in boys (Pnonlinear < .001) and in dichorionic (DC) twins (Pnonlinear = 0.03). Women with levels of FT4 lower than the 10th percentile had a higher risk of birth weight discordance in their offspring than women with normal FT4 levels (range, 2.5 to 97.5 percentiles) (odds ratio = 1.58; 95% CI, 1.05-2.33).

CONCLUSION

Our study suggests there was an association of FT4, but not TSH, with birth weight and birth weight discordance varied by sex and chorionicity. These findings could have implications for obstetricians to be aware of the importance of FT4 levels in preventing birth weight discordance in twin pregnancy.

Towards a science-based testing strategy to identify maternal thyroid hormone imbalance and neurodevelopmental effects in the progeny-part III: how is substance-mediated thyroid hormone imbalance in pregnant/lactating rats or their progeny related to neurodevelopmental effects?

This review investigated which patterns of thyroid- and brain-related effects are seen in rats upon gestational/lactational exposure to 14 substances causing thyroid hormone imbalance by four different modes-of-action (inhibition of thyroid peroxidase, sodium-iodide symporter and deiodinase activities, enhancement of thyroid hormone clearance) or to dietary iodine deficiency. Brain-related parameters included motor activity, cognitive function, acoustic startle response, hearing function, periventricular heterotopia, electrophysiology and brain gene expression. Specific modes-of-action were not related to specific patterns of brain-related effects. Based upon the rat data reviewed, maternal serum thyroid hormone levels do not show a causal relationship with statistically significant neurodevelopmental effects. Offspring serum thyroxine together with offspring serum triiodothyronine and thyroid stimulating hormone appear relevant to predict the likelihood for neurodevelopmental effects. Based upon the collated database, thresholds of ≥60%/≥50% offspring serum thyroxine reduction and ≥20% and statistically significant offspring serum triiodothyronine reduction indicate an increased likelihood for statistically significant neurodevelopmental effects; accuracies: 83% and 67% when excluding electrophysiology (and gene expression). Measurements of brain thyroid hormone levels are likely relevant, too. The extent of substance-mediated thyroid hormone imbalance appears more important than substance mode-of-action to predict neurodevelopmental impairment in rats. Pertinent research needs were identified, e.g. to determine whether the phenomenological offspring thyroid hormone thresholds are relevant for regulatory toxicity testing. The insight from this review shall be used to suggest a tiered testing strategy to determine whether gestational/lactational substance exposure may elicit thyroid hormone imbalance and potentially also neurodevelopmental effects.

Impact of endocrine disrupting chemicals on neurodevelopment: the need for better testing strategies for endocrine disruption-induced developmental neurotoxicity

INTRODUCTION

Brain development is highly dependent on hormonal regulation. Exposure to chemicals disrupting endocrine signaling has been associated with neurodevelopmental impairment. This raises concern about exposure to the suspected thousands of endocrine disruptors, and has resulted in efforts to improve regulation of these chemicals. Yet, the causal links between endocrine disruption and developmental neurotoxicity, which would be required for regulatory action, are still largely missing.

AREAS COVERED

In this review, we illustrate the importance of two endocrine systems, thyroid hormone and retinoic acid pathways, for neurodevelopment. We place special emphasis on TH and RA synthesis, metabolism, and how endocrine disrupting chemicals known or suspected to affect these systems are associated with developmental neurotoxicity.

EXPERT OPINION

While it is clear that neurodevelopment is dependent on proper hormonal functioning, and evidence is increasing for developmental neurotoxicity induced by endocrine disrupting chemicals, this is not grasped by current chemical testing. Thus, there is an urgent need to develop test methods detecting endocrine disruption in the context of neurodevelopment. Key to this development is further mechanistic insights on the involvement of endocrine signaling in neurodevelopment as well as increased support to develop and validate new test methods for the regulatory context.

Maternal Thyroid Anomalies and Attention-Deficit Hyperactivity Disorder in Progeny

Previous epidemiologic investigations suggested that maternal thyroid anomalies are a possible causal factor in attention-deficit hyperactivity disorder (ADHD) in progeny, yet clinical trials indicated that levothyroxine treatment was ineffective in preventing neurodevelopmental impairments. We used an Israeli cohort of 385,542 singleton births from 1999-2012 to explore the interrelated roles of maternal thyroid conditions, laboratory gestational thyroid hormone measurements, use of thyroid medications, and offspring ADHD. Analyses were performed using Cox proportional hazards models. Results indicated that maternal hypothyroidism diagnosis was associated with an elevated progeny ADHD hazard (adjusted hazard ratio = 1.14, 95% confidence interval = 1.10, 1.18). However, this association was unmitigated by gestational use of levothyroxine and was unexplained by maternal gestational thyroid hormone levels. Associations with gestational thyrotropin values and hypothyroxinemia were also observed but were robust only in mothers without other records indicative of a thyroid problem. Results indicated that maternal thyroid hypofunction was associated with progeny ADHD but possibly not due to a direct causal relationship. Instead, maternal thyroid hypofunction may serve as a proxy indicator for other factors that affect neurodevelopment through thyroid hormone independent pathways, which are thus unaffected by pharmaceutical treatments for thyroid hypofunction. Factors known to disrupt thyroid functioning should be examined for their independent ADHD-related effects.

The association between prenatal perfluoroalkyl substance exposure and symptoms of attention-deficit/hyperactivity disorder in 8-year-old children and the mediating role of thyroid hormones in the Hokkaido study

BACKGROUND

Disruption of thyroid hormone (TH) levels during pregnancy contributes to attention deficit hyperactivity disorder (ADHD). Exposure to perfluoroalkyl substances (PFAS) during gestation may affect levels of maternal and neonatal TH; however, little is known about the effect of PFAS on ADHD mediated by TH.

OBJECTIVES

We investigated the impact of maternal PFAS exposure on children's ADHD symptoms with the mediating effect of TH.

METHODS

In a prospective birth cohort (the Hokkaido study), we included 770 mother-child pairs recruited between 2002 and 2005 for whom both prenatal maternal and cord blood samples were available. Eleven PFAS were measured in maternal serum obtained at 28-32 weeks of gestation using ultra-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry. TH and thyroid antibody, including thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) were measured in maternal blood during early pregnancy (median 11 gestational weeks) and in cord blood at birth. ADHD symptoms in the children at 8 years of age were rated by their parents using the ADHD-Rating Scale (ADHD-RS). The cut-off value was set at the 80th percentile for each sex.

RESULTS

Significant inverse associations were found between some PFAS in maternal serum and ADHD symptoms among first-born children. Assuming causality, we found only one significant association: maternal FT4 mediated 17.6% of the estimated effect of perfluoroundecanoic acid exposure on hyperactivity-impulsivity among first-born children.

DISCUSSION

Higher PFAS levels in maternal serum during pregnancy were associated with lower risks of ADHD symptoms at 8 years of age. The association was stronger among first-born children in relation to hyperactivity-impulsivity than with regard to inattention. There was little mediating role of TH during pregnancy in the association between maternal exposure to PFAS and reduced ADHD symptoms at 8 years of age.

Associations between maternal thyroid function in pregnancy and child neurodevelopmental outcomes at 20 months in the Seychelles Child Development Study, Nutrition Cohort 2 (SCDS NC2)

Maternal thyroid hormones facilitate optimal foetal neurodevelopment; however, the exact role of the thyroid hormones on specific cognitive outcomes is unknown. The present study aimed to investigate associations between maternal thyroid function and neurodevelopmental outcomes in the Seychelles Child Development Study (SCDS) Nutrition 2 cohort (n 1328). Maternal free thyroid hormones (fT3, fT4 and fTSH) were assessed at 28 weeks' gestation with a range of child cognitive outcomes analysed at 20 months. Dietary iodine intake was analysed for a subset of women through a Food Frequency Questionnaire. Linear regression analysis was used to test associations between serum concentrations of maternal thyroid hormones and child neurodevelopment outcomes. Thyroid hormones were analysed as continuous data and categorised as quintiles. 95% of mothers had optimal thyroid function based on fTSH concentrations. Overall, the present study shows that maternal thyroid function is not associated with neurodevelopmental outcomes in this high fish-eating population. However, a positive association, using quintiles for fT3, was reported for the Mental Developmental Index, between Q3 v. Q4 (β 0⋅073; P 0⋅043) and for Q3 v. Q5 (β value 0⋅086; P 0⋅018). To conclude, mothers in our cohort, who largely have optimal thyroid function and iodine intakes, appear able to regulate thyroid function throughout pregnancy to meet neurodevelopmental needs. However, it is possible that minor imbalances of fT3, as indicated from our secondary analysis, may impact offspring neurodevelopment. Further investigation of the relationship between maternal thyroid function and infant neurodevelopment is warranted, particularly in populations with different dietary patterns and thereby iodine intakes.

Hyperthyroidism in Pregnancy: The Delicate Balance between Too Much or Too Little Antithyroid Drug

Overt hyperthyroidism (HT) during pregnancy is associated with a risk of maternal–fetal complications. Antithyroid drugs (ATD) have a potential risk for teratogenic effects and fetal–neonatal hypothyroidism. This study evaluated ATD treatment and thyroid function control during pregnancy, and pregnancy outcome in women with HT. Patients and methods: A retrospective analysis of 36 single fetus pregnancies in 29 consecutive women (median age 30.3 ± 4.7 years) with HT diagnosed before or during pregnancy; a control group of 39 healthy euthyroid pregnant women was used. Results: Twenty-six women had Graves’ disease (GD, 33 pregnancies), 1 had a hyperfunctioning autonomous nodule, and 2 had gestational transient thyrotoxicosis (GTT). Methimazole (MMI) was administered in 22 pregnancies (78.5%), Propylthiouracil (PTU) in 2 (7.1%), switch from MMI to PTU in 4 (14.2%), no treatment in 8 pregnancies (3 with subclinical HT, 5 euthyroid with previous GD remission before conception). In the 8 pregnancies of GD patients diagnosed during gestation or shortly before (<6 weeks), i.e., with fetal exposure to uncontrolled HT, there was 1 spontaneous abortion at 5 weeks (3.4% of all ATD-treated pregnancies), and 1 premature delivery at 32 weeks with neonatal death in 24 h (3.4%); 1 child had neonatal hyperthyroidism (3.3% of live children in GD women) and a small atrial sept defect (4% of live children in ATD treated women). In women treated more than 6 months until conception (20 pregnancies): (a) median ATD doses were lower than those in women diagnosed shortly before or during pregnancy; (b) ATD was withdrawn in 40% of pregnancies in trimester (T)1, all on MMI < 10 mg/day (relapse in 14.2%), and in up to 55% in T3; (c) TSH level was below normal in 37%, 35% and 22% of pregnancies in T1, T2 and T3 respectively; FT4 was increased in 5.8% (T1) and subnormal in 11.75% in T2 and T3; (d) no fetal birth defects were recorded; one fetal death due to a true umbilical cord knot was registered. Mean birth weight was similar in both ATD-treated and control groups. Hyperthyroidism relapsed postpartum in 83% of GD patients (at median 3 ± 2.6 months). Conclusion: In hyperthyroid women with long-term ATD treatment before conception, drugs could be withdrawn in T1 in 40% of them, the thyroid function control was better, and pregnancy and fetal complications were rarer, compared to women diagnosed during pregnancy. Frequent serum TSH and FT4 monitoring is needed to maintain optimal thyroid function during pregnancy.

Testing for heterotopia formation in rats after developmental exposure to selected in vitro inhibitors of thyroperoxidase

The thyroperoxidase (TPO) enzyme is expressed by the thyroid follicular cells and is required for thyroid hormone synthesis. In turn, thyroid hormones are essential for brain development, thus inhibition of TPO in early life can have life-long consequences for brain function. If environmental chemicals with the capacity to inhibit TPO in vitro can also alter brain development in vivo through thyroid hormone dependent mechanisms, however, remains unknown. In this study we show that the in vitro TPO inhibiting pesticide amitrole alters neuronal migration and induces periventricular heterotopia; a thyroid hormone dependent brain malformation. Perinatal exposure to amitrole reduced pup serum thyroxine (T4) concentrations to less than 50% of control animals and this insufficiency led to heterotopia formation in the 16-day old pup's brain. Two other in vitro TPO inhibitors, 2-mercaptobenzimidazole and cyanamide, caused reproductive toxicity and had only minor sporadic effects on the thyroid hormone system; consequently, they did not cause heterotopia. This is the first demonstration of an environmental chemical causing heterotopia, a brain malformation until now only reported for rodent studies with the anti-thyroid drugs propylthiouracil and methimazole. Our results highlight that certain TPO-inhibiting environmental chemicals can alter brain development through thyroid hormone dependent mechanisms. Improved understanding of the effects on the brain as well as the conditions under which chemicals can perturb brain development will be key to protect human health.

The association between COVID-19 pandemic and maternal isolated hypothyroxinemia in first and second trimesters

BACKGROUND

The outbreak of COVID-19 epidemic has induced entire cities in China placed under 'mass quarantine'. The majority of pregnant women have to be confined at home may be more vulnerable to stressors. In our study, we aimed to explore the effects of the epidemic on maternal thyroid function, so as to provide evidence for prevention and intervention of sustained maternal and offspring's health impairment produced by thyroid dysfunction.

METHODS

The subjects were selected from an ongoing prospective cohort study. we included the pregnant women who receive a thyroid function test during the COVID-19 epidemic and those receiving the test during the corresponding lunar period of 2019. A total of 7148 pregnant women with complete information were included in the final analysis. Multivariate linear and logistic regression models were used for analyzing the association of COVID-19 pandemic with FT4 levels and isolated hypothyroxinemia.

RESULTS

We found a decreased maternal FT4 level during the period of the COVID-19 pandemic in first and second trimesters (β = -0. 131, 95%CI = -0.257,-0.006，p = 0.040) and in first trimester (β = -0. 0.176, 95%CI = -0.326,-0.026，p = 0.022) when adjusting for 25 (OH) vitamin D, vitamin B12, folate and ferritin and gestational days, maternal socio-demographic characteristics and health conditions. The status of pandemic increased the risks of isolated hypothyroxinemia in first and second trimesters (OR = 1.547, 95%CI = 1.251,1.913, p < 0.001) and first trimester (OR = 1.651, 95%CI = 1.289,2.114, p < 0.001) when adjusting for the covariates. However, these associations disappeared in the women with positive TPOAb (p > 0.05). Additionally, we found associations between daily reported new case of COVID-19 and maternal FT4 for single-day lag1, lag3 and multi-day lag01 and lag04 when adjusting for the covariates (each p < 0.05).

CONCLUSIONS

Mass confinement as a primary community control strategy may have a significant cost to public health resources. Access to health service systems and adequate medical resources should be improved for pregnant women during the COVID-19 pandemic.

Umbilical cord serum perfluoroalkyl substance mixtures in relation to thyroid function of newborns: Findings from Sheyang Mini Birth Cohort Study

BACKGROUND

The epidemiological evidence on the associations between prenatal exposure to perfluoroalkyl substances (PFAS) and thyroid hormones in newborns was inconclusive.

OBJECTIVES

We aimed to estimate associations of fetal exposure to PFAS individually and in mixtures with thyroid function of newborns.

METHODS

A total of 490 mother-newborn pairs were included from Sheyang Mini Birth Cohort Study (SMBCS), a prospective cohort that recruited between June 2009 and January 2010. 12 PFAS and 7 thyroid function indicators were quantified in umbilical cord serum. We examined associations of prenatal exposure to individual and a mixture of PFAS with thyroid function indicators using multivariable linear regression and weighted quantile sum (WQS) regression models with adjustment for potential confounders, respectively.

RESULTS

Higher cord serum concentrations of PFAS mixtures were related to increases in TT4 and FT4 levels, and reductions in TSH concentrations of newborns. Combining single-chemical models with multiple-chemical models, PFOS, PFNA and PFUnDA were associated with increased TT4 levels with contributing to the mixture effects of 46.4%, 22.8%, and 16.7%, respectively. PFOS exposure was in positive association with cord serum FT4 concentrations and contributed 28.9% to the joint effects of mixtures. PFNA and PFHpA were the most important contributors to the decreases of TSH levels of newborns with 46.3% and 45.0% among the mixtures, respectively.

CONCLUSIONS

The current findings indicated the thyroid disruption of individual PFAS and their mixtures in cord serum. Additional studies are warranted to explore the underlying biological mechanisms, particularly for PFAS mixtures.

Associations of Maternal Androgen-Related Conditions With Risk of Autism Spectrum Disorder in Progeny and Mediation by Cardiovascular, Metabolic, and Fertility Factors

Fetal exposure to elevated androgens is thought to contribute to autism spectrum disorder (ASD) risk. However, data rely heavily on in utero androgens measurements, which also reflect fetal secretions. Thus, in utero hyperandrogenemia might indicate adverse autism-related neurogenesis that has already occurred affecting fetal androgen homeostasis, rather than being a cause of the disorder. Associations between maternal androgen-related conditions and ASD could more directly implicate androgens' etiological role. We examined the association between maternal hyperandrogenemia-related conditions, focusing primarily on polycystic ovarian syndrome (PCOS), and progeny ASD, in an Israeli cohort of 437,222 children born in 1999-2013. Odds ratios and 95% confidence intervals were estimated using generalized estimating equations. Multiple mediation analyses using natural effect models were conducted to evaluate combined mediation of the PCOS effect by androgen-related cardiovascular, metabolic, and fertility factors. Results indicated that children of mothers with PCOS had higher ASD odds compared with children of mothers without PCOS (odds ratio = 1.42, 95% confidence interval: 1.24,1.64), and this effect was only partly mediated by the factors considered. Elevated odds were also observed for other hyperandrogenemia-related conditions. Findings provide support for direct involvement of maternal hyperandrogenemia in ASD etiology. Alternatively, findings might reflect shared genetic and/or environmental factors independently affecting maternal androgen homeostasis and fetal neurodevelopment.

Maternal Thyroid Disorders and Risk of Autism Spectrum Disorder in Progeny

BACKGROUND

Maternal thyroid dysfunction is suspected of causing adverse neurodevelopmental effects, but current evidence is inconclusive. Epidemiologic investigations generally suggest an association between maternal thyroid dysfunction and neurodevelopment impairments in progeny, but clinical trials of thyroid treatment during pregnancy reported null effects. To better understand these discrepant findings, we evaluated the association between maternal thyroid conditions and autism spectrum disorder (ASD), including examining the role of gestational thyroid-related hormone concentrations and thyroid medications use.

METHODS

Analyses considered 437,222 singleton live births occurring in a large Israeli health fund in 1999-2013, followed through 2016. Thyroid conditions and ASD cases were identified through International Classification of Diseases-9 codes with subsequent validation through review of medical records. Laboratory gestational thyroid hormone measurements were also considered.

RESULTS

Children of mothers who ever experienced hypothyroidism had a higher risk of ASD compared with children of mothers without hypothyroidism (adjusted odds ratio [aOR] = 1.26, 95% confidence interval [CI] = 1.12, 1.42). The association with hyperthyroidism was less consistent, but elevated in main analyses (aOR = 1.42, 95% CI = 1.04, 1.94). These associations were not explained by maternal gestational thyroid hormones levels nor mitigated by gestational use of thyroid medications.

CONCLUSIONS

Results indicate that maternal thyroid conditions are associated with increased ASD risk in progeny, but suggestively not due to direct effects of thyroid hormones. Instead, factors that influence maternal thyroid function could have etiologic roles in ASD through pathways independent of maternal gestational thyroid hormones and thus be unaffected by medication treatment. Factors known to disrupt thyroid function should be examined for possible involvement in ASD etiology.

A profile and review of findings from the Early Markers for Autism study: unique contributions from a population-based case-control study in California

BACKGROUND

The Early Markers for Autism (EMA) study is a population-based case-control study designed to learn more about early biologic processes involved in ASD.

METHODS

Participants were drawn from Southern California births from 2000 to 2003 with archived prenatal and neonatal screening specimens. Across two phases, children with ASD (n = 629) and intellectual disability without ASD (ID, n = 230) were ascertained from the California Department of Developmental Services (DDS), with diagnoses confirmed according to DSM-IV-TR criteria based on expert clinical review of abstracted records. General population controls (GP, n = 599) were randomly sampled from birth certificate files and matched to ASD cases by sex, birth month and year after excluding individuals with DDS records. EMA has published over 20 papers examining immune markers, endogenous hormones, environmental chemicals, and genetic factors in association with ASD and ID. This review summarizes the results across these studies, as well as the EMA study design and future directions.

RESULTS

EMA enabled several key contributions to the literature, including the examination of biomarker levels in biospecimens prospectively collected during critical windows of neurodevelopment. Key findings from EMA include demonstration of elevated cytokine and chemokine levels in maternal mid-pregnancy serum samples in association with ASD, as well as aberrations in other immune marker levels; suggestions of increased odds of ASD with prenatal exposure to certain endocrine disrupting chemicals, though not in mixture analyses; and demonstration of maternal and fetal genetic influence on prenatal chemical, and maternal and neonatal immune marker and vitamin D levels. We also observed an overall lack of association with ASD and measured maternal and neonatal vitamin D, mercury, and brain-derived neurotrophic factor (BDNF) levels.

LIMITATIONS

Covariate and outcome data were limited to information in Vital Statistics and DDS records. As a study based in Southern California, generalizability for certain environmental exposures may be reduced.

CONCLUSIONS

Results across EMA studies support the importance of the prenatal and neonatal periods in ASD etiology, and provide evidence for the role of the maternal immune response during pregnancy. Future directions for EMA, and the field of ASD in general, include interrogation of mechanistic pathways and examination of combined effects of exposures.

Hyperthyroidism in pregnancy: evidence and hypothesis in fetal programming and development

The management of hyperthyroidism in pregnant patients has been a topic of raised clinical awareness for decades. It is a strong recommendation that overt hyperthyroidism of Graves' disease in pregnant women should be treated to prevent complications. The consequences of hyperthyroidism in pregnancy are less studied than hypothyroidism, and a literature review illustrates that the main burden of evidence to support current clinical guidance emerges from early observations of severe complications in Graves' disease patients suffering from untreated hyperthyroidism in the pregnancy. On the other hand, the more long-term consequences in children born to mothers with hyperthyroidism are less clear. A hypothesis of fetal programming by maternal hyperthyroidism implies that excessive levels of maternal thyroid hormones impair fetal growth and development. Evidence from experimental studies provides clues on such mechanisms and report adverse developmental abnormalities in the fetal brain and other organs. Only few human studies addressed developmental outcomes in children born to mothers with hyperthyroidism and did not consistently support an association. In contrast, large observational human studies performed within the last decade substantiate a risk of teratogenic side effects to the use of antithyroid drugs in early pregnancy. Thus, scientific and clinical practice are challenged by the distinct role of the various exposures associated with Graves' disease including the hyperthyroidism per se, the treatment, and thyroid autoimmunity. More basic and clinical studies are needed to extend knowledge on the effects of each exposure, on the potential interaction between exposures and with other determinants, and on the underlying mechanisms.

Association of Maternal Hypothyroidism With Cardiovascular Diseases in the Offspring

BACKGROUND

No previous study has examined the effect of maternal hypothyroidism on a broad spectrum of cardiovascular disease (CVD) endpoints in the offspring.

METHODS

A nationwide population-based cohort study based on the linkage of several Danish nationwide registries was conducted to explore whether maternal hypothyroidism is associated with offspring's CVD. Altogether 1,041,448 singletons born between the 1st of January 1978 and the 31st of December 1998 were investigated from the age of 8 years to the 31st of December 2016. Exposure was maternal diagnosis of hypothyroidism across lifespan and the outcome of interest was a CVD diagnosis in the offspring. Cox regression models were performed to estimate the hazard ratios (HRs) of CVD.

RESULTS

Offspring born to mothers with hypothyroidism had an increased risk of CVD (hazard ratios (HR)=1.23, 95% confidence interval (CI): 1.12-1.35), and of several subcategories of CVD including hypertension, arrhythmia, and acute myocardial infarction in offspring. The magnitude of association was the most pronounced in an exposure occur during pregnancy (HR=1.71, 95% CI: 1.10-2.67), which is consistent across all the subgroup analysis, including sibling analysis.

CONCLUSIONS

Maternal hypothyroidism is associated with an increased risk of CVD in offspring. Thyroid hormone insufficiency during pregnancy may predominantly contribute to the observed associations; however, the effects of a shared genetic background and a time-stable familial environment/lifestyle factors cannot be excluded.

Inadequate iodine intake in lactating women in Sweden: A pilot 1-year, prospective, observational study

INTRODUCTION

Breastfed infants depend on breast-milk iodine for growth and brain development, as iodine is a trace element important for thyroid hormone production. Iodine need is higher during lactation; hence, mothers and children are at risk of iodine deficiency. We aimed to explore maternal iodine and thyroidal status during lactation.

MATERIAL AND METHODS

Pregnant women were recruited in Gothenburg, southwest Sweden. Maternal urine and serum were collected at pregnancy week 35-37 (n = 84) and 0.5, 4, and 12 months postpartum. Seventy mothers provided breast milk at 0.5 months.

RESULTS

Median (interquartile range) breast-milk iodine concentration was 90 (66-116) μg/L. About 58% had breast-milk iodine concentration <100 μg/L. Iodine supplement users (n = 13) had higher breast-milk iodine concentration than non-users (n = 49) (140 μg/L vs 71 μg/L, P = .001). Exclusively breastfeeding women at 4 months postpartum (n = 57) had lower median urinary iodine concentration (85 μg/L vs 133 μg/L, P = .004) and higher thyroglobulin serum concentration (22.3 μg/L vs 11.8 μg/L, P = .032) than non-exclusively breastfeeding women (n = 25). Concentrations of thyroid hormones were unaffected.

CONCLUSIONS

This pilot study suggests that lactating women in southwest Sweden present mildly inadequate iodine intake, mainly among non-iodine supplement users and exclusively breastfeeding mothers. Studies on the coverage of the iodine fortification program in breastfeeding women are warranted.

Toward a science-based testing strategy to identify maternal thyroid hormone imbalance and neurodevelopmental effects in the progeny - part I: which parameters from human studies are most relevant for toxicological assessments?

The 2018 European Food Safety Authority/European Chemicals Agency Guidance on the Identification of Endocrine Disruptors lacks clarity on how the presence or absence of substance-induced maternal thyroid hormone imbalance, or the potential for subsequent deleterious consequences in child neurodevelopment, should be established by toxicological assessments. To address these uncertainties, this narrative review evaluates human evidence on how altered maternal thyroid function may be associated with child neurodevelopmental outcomes; and seeks to identify parameters in human studies that appear most relevant for toxicological assessments. Serum levels of free thyroxine (fT4) and thyroid stimulating hormone (TSH) are most frequently measured when assessing thyroid function in pregnant women, whereas a broad spectrum of neurodevelopmental parameters is used to evaluate child neurodevelopment. The human data confirms an association between altered maternal serum fT4 and/or TSH and increased risk for child neurodevelopmental impairment. Quantitative boundaries of effects indicative of increased risks need to be established. Moreover, it is unknown if altered serum levels of total T4, free or total triiodothyronine, or parameters unrelated to serum thyroid hormones might be more relevant indicators of such effects. None of the human studies established a link between substance-mediated liver enzyme induction and increased serum thyroid hormone clearance, let alone further to child neurodevelopmental impairment. This review identifies research needs to contribute to the development of toxicity testing strategies, to reliably predict whether substances have the potential to impair child neurodevelopment via maternal thyroid hormone imbalance.

Maternal iodine status in a multi-ethnic UK birth cohort: associations with autism spectrum disorder

Background

Maternal iodine requirements increase during pregnancy to supply thyroid hormones essential for fetal brain development. Maternal iodine deficiency can lead to hypothyroxinemia, a reduced fetal supply of thyroid hormones which, in the first trimester, has been linked to an increased risk of autism spectrum disorder (ASD) in the child. No study to date has explored the direct link between maternal iodine deficiency and diagnosis of ASD in offspring.

Methods

Urinary iodine concentrations (UIC) and iodine/creatinine ratios (I:Cr) were measured in 6955 mothers at 26–28 weeks gestation participating in the Born in Bradford (BiB) cohort. Maternal iodine status was examined in relation to the probability of a Read (CTV3) code for autism being present in a child’s primary care records through a series of logistic regression models with restricted cubic splines.

Results

Median (inter-quartile range) UIC was 76 μg/L (46, 120) and I:Cr was 83 μg/g (59, 121) indicating a deficient population according to WHO guidelines. Ninety two children (1·3%) in our cohort had received a diagnosis of ASD by the census date. Overall, there was no evidence to support an association between I:Cr or UIC and ASD risk in children aged 8–12 years (p = 0·3).

Conclusions

There was no evidence of an increased clinical ASD risk in children born to mothers with mild-to-moderate iodine deficiency at 26 weeks gestation. Alternative functional biomarkers of exposure and a wider range of conditions may provide further insight.

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

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

Management of Graves Thyroidal and Extrathyroidal Disease: An Update

CONTEXT

Invited update on the management of systemic autoimmune Graves disease (GD) and associated Graves orbitopathy (GO).

EVIDENCE ACQUISITION

Guidelines, pertinent original articles, systemic reviews, and meta-analyses.

EVIDENCE SYNTHESIS

Thyrotropin receptor antibodies (TSH-R-Abs), foremost the stimulatory TSH-R-Abs, are a specific biomarker for GD. Their measurement assists in the differential diagnosis of hyperthyroidism and offers accurate and rapid diagnosis of GD. Thyroid ultrasound is a sensitive imaging tool for GD. Worldwide, thionamides are the favored treatment (12-18 months) of newly diagnosed GD, with methimazole (MMI) as the preferred drug. Patients with persistently high TSH-R-Abs and/or persistent hyperthyroidism at 18 months, or with a relapse after completing a course of MMI, can opt for a definitive therapy with radioactive iodine (RAI) or total thyroidectomy (TX). Continued long-term, low-dose MMI administration is a valuable and safe alternative. Patient choice, both at initial presentation of GD and at recurrence, should be emphasized. Propylthiouracil is preferred to MMI during the first trimester of pregnancy. TX is best performed by a high-volume thyroid surgeon. RAI should be avoided in GD patients with active GO, especially in smokers. Recently, a promising therapy with an anti-insulin-like growth factor-1 monoclonal antibody for patients with active/severe GO was approved by the Food and Drug Administration. COVID-19 infection is a risk factor for poorly controlled hyperthyroidism, which contributes to the infection-related mortality risk. If GO is not severe, systemic steroid treatment should be postponed during COVID-19 while local treatment and preventive measures are offered.

CONCLUSIONS

A clear trend towards serological diagnosis and medical treatment of GD has emerged.

Maternal Thyroid Dysfunction During Pregnancy and the Risk of Adverse Outcomes in the Offspring: A Systematic Review and Meta-Analysis

CONTEXT

Previous studies suggested a potential link of maternal thyroid dysfunction with adverse neurocognitive outcomes and impaired development of internal organs in offspring.

OBJECTIVE

To review the association between maternal thyroid dysfunction and the risk of adverse outcomes in offspring.

DATA SOURCES

PubMed, EMBASE, and Cochrane Library.

STUDY SELECTIONS

Eligible studies reported the association between maternal thyroid hormone function and the risk of adverse outcomes in their children.

DATA EXTRACTION

Reviewers extracted data on study characteristics and results independently.

DATA SYNTHESIS

Estimates were pooled and reported as odds ratio (OR) with 95% confidence interval (CI). I2 tests were applied to assess the heterogeneity across studies.

RESULTS

We identified 29 eligible articles and found an association between maternal hyperthyroidism and attention deficit hyperactivity disorder (ADHD) (OR: 1.18, 95% CI: 1.04-1.34, I2 = 0%) and epilepsy (OR: 1.19, 95% CI: 1.08-1.31, I2 = 0%) in offspring; as well as an association of maternal hypothyroidism with increased risk of ADHD (OR: 1.14, 95% CI: 1.03-1.26, I2 = 25%), autism spectrum disorder (OR: 1.41, 95% CI: 1.05-1.90, I2 = 63%), and epilepsy (OR: 1.21, 95% CI: 1.06-1.39, I2 = 0%) in offspring.

CONCLUSION

Routine measurement and timely treatment on thyroid function should be considered for pregnant women.

The association between thyroid function biomarkers and attention deficit hyperactivity disorder

The relation between thyroid function biomarkers and attention deficit hyperactivity disorder (ADHD) in children and adolescents is currently unclear. Cross-sectional data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS Baseline) was analyzed to assess the association between thyroid function biomarkers and ADHD in a population-based, nationally representative sample. The study cohort included 11,588 children and adolescents with 572 and 559 having an ADHD diagnosis or symptoms, respectively. ADHD symptoms were assessed through the Inattention/Hyperactivity subscale of the Strength and Difficulties Questionnaire. ADHD diagnosis was determined by a physician or psychologist. Serum thyroid stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) concentrations were determined enzymatically. Adjusted regression models were used to relate serum TSH, fT3, and fT4 with risk for ADHD diagnosis or symptoms. In children, a 1 mIU/l higher TSH was related to a 10% lower risk (odds ratio [OR] 0.90; 95% confidence interval [CI] 0.81-1.00) of ADHD diagnosis. We found a significant positive association between fT3 and continuously assessed ADHD symptoms in children (β 0.08; 95% CI 0.03-0.14). Our results suggest that physical maturity may influence the association between thyroid function biomarkers and risk for ADHD.

Endocrine Insights into the Pathophysiology of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a class of neurodevelopmental disorders that affects males more frequently than females. Numerous genetic and environmental risk factors have been suggested to contribute to the development of ASD. However, no one factor can adequately explain either the frequency of the disorder or the male bias in its prevalence. Gonadal, thyroid, and glucocorticoid hormones all contribute to normal development of the brain, hence perturbations in either their patterns of secretion or their actions may constitute risk factors for ASD. Environmental factors may contribute to ASD etiology by influencing the development of neuroendocrine and neuroimmune systems during early life. Emerging evidence suggests that the placenta may be particularly important as a mediator of the actions of environmental and endocrine risk factors on the developing brain, with the male being particularly sensitive to these effects. Understanding how various risk factors integrate to influence neural development may facilitate a clearer understanding of the etiology of ASD.

Neonatal thyroid-stimulating hormone and association with attention-deficit/hyperactivity disorder

BACKGROUND

Normal brain development is dependent on maternal, fetal and neonatal thyroid function. Measuring neonatal thyroid-stimulating hormone (TSH) 48-72 hours after birth screens for congenital hypothyroidism, allowing early treatment to avoid serious impairment. However, even within sub-clinical ranges, disrupted thyroid homeostasis during brain development has been linked to adverse neurodevelopmental outcomes, including attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVES

To estimate the association between neonatal TSH below threshold for potential congenital hypothyroidism and subsequent ADHD diagnosis using a population-based birth cohort.

METHODS

Children with a diagnosis of ADHD in the Norwegian Mother, Father and Child Cohort Study (MoBa) were identified through linkage with the Norwegian Patient Registry using ICD-10 codes for hyperkinetic disorders. The study included 405 ADHD cases and 1,092 controls (born 2003-2008) with available neonatal TSH concentrations below 10 mU/L (cut-off for potential congenital hypothyroidism) measured in dried blood spots sampled 48-72 hours after birth.

RESULTS

In multivariable, quintile models the relationship appeared to follow a U-shaped pattern with elevated odds ratios (OR) at lower and higher TSH levels. Among children with TSH in the lowest quintile, odds of ADHD was approximately 1.5-fold higher than children in the middle quintile (OR 1.60, 95% CI 1.09, 2.34), which was driven by substantially elevated risk among girls, with no association among boys (P_interaction = 0.02; girls OR 3.10, 95% CI 1.53, 6.30; boys OR 1.16, 95% CI 0.73, 1.84).

CONCLUSIONS

ADHD risk appeared to be elevated among newborns with low TSH levels (i.e. with hyperthyroid status), and this association was mainly found among girls. Because our findings are suggestive of increased risk at very low TSH concentrations, where analytical accuracy is low, future studies should employ highly sensitive assays capable of accurate quantitation at very low concentrations. Also, larger studies are needed to investigate these associations at higher neonatal TSH concentrations where data are more widely distributed.

Thyroid function abnormalities and thyroid autoantibodies in Danish pregnant women

OBJECTIVE

Abnormal thyroid function in pregnant women is a matter of concern. Knowledge on the occurrence of known and unidentified thyroid function abnormalities in a large unselected cohort of pregnant women is warranted as part of the debate on benefits and risks of routine testing.

DESIGN

Cohort study.

PARTICIPANTS

A total of 14 323 pregnant women in the North Denmark Region, who had a blood sample drawn as part of the prenatal screening program in early pregnancy (2011-2015).

MEASUREMENTS

TSH, free thyroxine, thyroid peroxidase and thyroglobulin antibodies were measured in the stored blood samples using an automatic immunoassay (ADVIA Centaur XPT, Siemens Healthineers). Cohort-, method- and week-specific reference ranges were used for classification of maternal thyroid function, and a cut-off of 60 U/mL was used for thyroid autoantibodies. Information in Danish nationwide registers was used to identify diagnosed and treated maternal thyroid disease.

RESULTS

Overall, 15.2% had thyroid function abnormalities in the early pregnancy and 14.9% were thyroid peroxidase and/or thyroglobulin antibody positive. Among women with known thyroid disease (n = 365), the frequency of abnormal thyroid function was 45.7%, and 62.8% in women (n = 172) who received current treatment in the pregnancy. When maternal thyroid disease was diagnosed in the years following pregnancy (n = 313), 46.7% had abnormal thyroid function and 54.3% were thyroid peroxidase and/or thyroglobulin antibody positive in the early pregnancy.

CONCLUSION

Thyroid function abnormalities and thyroid autoantibodies were common in Danish pregnant women, particularly in women with known or later diagnosed thyroid disease, which raises concern about inadequately treated and unidentified abnormal thyroid function.

Universal screening for thyroid disease during pregnancy should be performed

Thyroid disease can significantly impact the pregnant woman and her child. Human and animal studies have firmly linked overt hypothyroidism and overt hyperthyroidism to miscarriage, preterm delivery and other adverse pregnancy outcomes. Overt hypothyroidism and overt hyperthyroidism affect 1% of all pregnancies. Treatment is widely available, and if detected early, results in decreased rates of adverse outcomes. Universal screening for thyroid disease in pregnancy can identify patients with thyroid disease requiring treatment, and ultimately decrease rates of complications. Universal screening is cost-effective compared to the currently accepted practice of targeted screening and may even be cost-saving in some healthcare systems. Targeted screening, which is recommended by most professional associations, fails to detect a large proportion of pregnant women with thyroid disease. In fact, an increasing number of providers are performing universal screening for thyroid disease in pregnancy, contrary to society guidelines. Limited evidence concerning the impact of untreated and treated subclinical disease and thyroid autoimmunity has distracted from the core rationale for universal screening - the beneficial impact of detecting and treating overt thyroid disease. Evidence supporting universal screening for overt disease stands independently from that of subclinical and autoimmune disease. The time to initiate universal screening is now.

Modeled prenatal exposure to per- and polyfluoroalkyl substances in association with child autism spectrum disorder: A case-control study

BACKGROUND/OBJECTIVE

Per- and polyfluoroalkyl substances (PFAS) display neurobehavioral toxicity in laboratory animal studies. We examined associations of modeled prenatal maternal exposure to PFAS with child diagnosis of autism spectrum disorder (ASD).

METHODS

Participants were 453 mother-child pairs from CHARGE (CHildhood Autism Risk from Genetics and Environment), a population-based case-control study. Children underwent psychometric testing and were clinically confirmed for ASD (n = 239) or typical development (TD, n = 214). At the end of the clinic visit, maternal blood specimens were collected. We quantified nine PFAS in maternal serum samples collected when their child was 2-5 years old. As surrogate in utero exposure, we used a model built from external prospective data in pregnancy and 24 months post-partum and then reconstructed maternal PFAS serum concentrations during pregnancy in this case-control sample. We used logistic regression to evaluate associations of modeled prenatal maternal PFAS concentrations with child ASD.

RESULTS

Modeled prenatal maternal perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS) were borderline associated with increased odds of child diagnosis of ASD (per nanogram per milliliter increase: odds ratio [OR] = 1.46; 95% confidence interval [CI]: 0.98, 2.18 for PFHxS, OR = 1.03; 95% CI: 0.99, 1.08 for PFOS). When compared to the lowest quartile (reference category), the highest quartile of modeled prenatal maternal PFHxS was associated with increased odds of child diagnosis of ASD (OR = 1.95; 95% CI: 1.02, 3.72).

CONCLUSIONS

In analyses where modeled prenatal maternal PFAS serum concentrations served as in utero exposure, we observed that prenatal PFHxS and PFOS exposure, but not other PFAS, were borderline associated with increased odds of child diagnosis of ASD. Further studies in which PFAS concentrations are prospectively measured in mothers and children at a range of developmental stages are needed to confirm these findings.