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Context Interpretation of thyroid function tests during pregnancy is limited by the generalizability of reference intervals between cohorts due to inconsistent methodology. Objective (1) To provide an overview of published reference intervals for thyrotropin (TSH) and free thyroxine (FT4) in pregnancy, (2) to assess the consequences of common methodological between-study differences by combining raw data from different cohorts. Methods (1) Ovid MEDLINE, EMBASE, and Web of Science were searched until December 12, 2021. Studies were assessed in duplicate. (2) The individual participant data (IPD) meta-analysis was performed in participating cohorts in the Consortium on Thyroid and Pregnancy. Results (1) Large between-study methodological differences were identified, 11 of 102 included studies were in accordance with current guidelines; (2) 22 cohorts involving 63 198 participants were included in the meta-analysis. Not excluding thyroid peroxidase antibody–positive participants led to a rise in the upper limits of TSH in all cohorts, especially in the first (mean +17.4%; range +1.6 to +30.3%) and second trimester (mean +9.8%; range +0.6 to +32.3%). The use of the 95th percentile led to considerable changes in upper limits, varying from –10.8% to –21.8% for TSH and –1.2% to –13.2% for FT4. All other additional exclusion criteria changed reference interval cut-offs by a maximum of 3.5%. Applying these findings to the 102 studies included in the systematic review, 48 studies could be used in a clinical setting. Conclusion We provide an overview of clinically relevant reference intervals for TSH and FT4 in pregnancy. The results of the meta-analysis indicate that future studies can adopt a simplified study setup without additional exclusion criteria.

BACKGROUND: Adequate maternal thyroid function is important for an uncomplicated pregnancy. Although multiple observational studies have evaluated the association between thyroid dysfunction and hypertensive disorders of pregnancy, the methods and definitions of abnormalities in thyroid function tests were heterogeneous, and the results were conflicting. We aimed to examine the association between abnormalities in thyroid function tests and risk of gestational hypertension and pre-eclampsia. METHODS: In this systematic review and meta-analysis of individual-participant data, we searched MEDLINE (Ovid), Embase, Scopus, and the Cochrane Database of Systematic Reviews from date of inception to Dec 27, 2019, for prospective cohort studies with data on maternal concentrations of thyroid-stimulating hormone (TSH), free thyroxine (FT(4)), thyroid peroxidase (TPO) antibodies, individually or in combination, as well as on gestational hypertension, pre-eclampsia, or both. We issued open invitations to study authors to participate in the Consortium on Thyroid and Pregnancy and to share the individual-participant data. We excluded participants who had pre-existing thyroid disease or multifetal pregnancy, or were taking medications that affect thyroid function. The primary outcomes were documented gestational hypertension and pre-eclampsia. Individual-participant data were analysed using logistic mixed-effects regression models adjusting for maternal age, BMI, smoking, parity, ethnicity, and gestational age at blood sampling. The study protocol was registered with PROSPERO, CRD42019128585. FINDINGS: We identified 1539 published studies, of which 33 cohorts met the inclusion criteria and 19 cohorts were included after the authors agreed to participate. Our study population comprised 46 528 pregnant women, of whom 39 826 (85·6%) women had sufficient data (TSH and FT(4) concentrations and TPO antibody status) to be classified according to their thyroid function status. Of these women, 1275 (3·2%) had subclinical hypothyroidism, 933 (2·3%) had isolated hypothyroxinaemia, 619 (1·6%) had subclinical hyperthyroidism, and 337 (0·8%) had overt hyperthyroidism. Compared with euthyroidism, subclinical hypothyroidism was associated with a higher risk of pre-eclampsia (2·1% vs 3·6%; OR 1·53 [95% CI 1·09-2·15]). Subclinical hyperthyroidism, isolated hypothyroxinaemia, or TPO antibody positivity were not associated with gestational hypertension or pre-eclampsia. In continuous analyses, both a higher and a lower TSH concentration were associated with a higher risk of pre-eclampsia (p=0·0001). FT(4) concentrations were not associated with the outcomes measured. INTERPRETATION: Compared with euthyroidism, subclinical hypothyroidism during pregnancy was associated with a higher risk of pre-eclampsia. There was a U-shaped association of TSH with pre-eclampsia. These results quantify the risks of gestational hypertension or pre-eclampsia in women with thyroid function test abnormalities, adding to the total body of evidence on the risk of adverse maternal and fetal outcomes of thyroid dysfunction during pregnancy. These findings have potential implications for defining the optimal treatment target in women treated with levothyroxine during pregnancy, which needs to be assessed in future interventional studies. FUNDING: Arkansas Biosciences Institute and Netherlands Organization for Scientific Research.

Context The impact of Hashimoto thyroiditis (HT) on the risk of thyroid cancer and its accurate detection remains unclear. The presence of a chronic lymphocytic infiltration imparts a logical mechanism potentially altering neoplastic transformation, while also influencing the accuracy of diagnostic evaluation. Methods We performed a prospective, cohort analysis of 9851 consecutive patients with 21,397 nodules ≥1 cm who underwent nodule evaluation between 1995 and 2017. The definition of HT included (i) elevated thyroid peroxidase antibody (TPOAb) level and/or (ii) findings of diffuse heterogeneity on ultrasound, and/or (iii) the finding of diffuse lymphocytic thyroiditis on histopathology. The impact of HT on the distribution of cytology and, ultimately, on malignancy risk was determined. Results A total of 2651 patients (27%) were diagnosed with HT, and 3895 HT nodules and 10,168 non-HT nodules were biopsied. The prevalence of indeterminate and malignant cytology was higher in the HT vs non-HT group (indeterminate: 26.3% vs 21.8%, respectively, P < 0.001; malignant: 10.0% vs 6.4%, respectively, P < 0.001). Ultimately, the risk of any nodule proving malignant was significantly elevated in the setting of HT (relative risk, 1.6; 95% CI, 1.44 to 1.79; P < 0.001), and was maintained when patients with solitary or multiple nodules were analyzed separately (HT vs non-HT: 24.5% vs 16.3% solitary; 22.1% vs 15.4% multinodular; P < 0.01). Conclusion HT increases the risk of thyroid malignancy in any patient presenting for nodule evaluation. Diffuse sonographic heterogeneity and/or TPOAb positivity should be used for risk assessment at time of evaluation.

The incidence of differentiated thyroid carcinoma (DTC) has increased rapidly over the past several years. Thus far, the only conclusively established risk factor for developing DTC is exposure to ionizing radiation, especially when the exposure occurs in childhood. Since the number of childhood cancer survivors (CCS) is increasing due to improvements in treatment and supportive care, the number of patients who will develop DTC after surviving childhood cancer (secondary thyroid cancer) is also expected to rise. Currently, there are no recommendations for management of thyroid cancer specifically for patients who develop DTC as a consequence of cancer therapy during childhood. Since complications or late effects from prior cancer treatment may elevate the risk of toxicity from DTC therapy, the medical history of CCS should be considered carefully in choosing DTC treatment. In this paper, we emphasize how the occurrence and treatment of the initial childhood malignancy affects the medical and psychosocial factors that will play a role in the diagnosis and treatment of a secondary DTC. We present considerations for clinicians to use in the management of patients with secondary DTC, based on the available evidence combined with experience-based opinions of the authors.

BACKGROUND: Adequate transplacental passage of maternal thyroid hormone is important for normal fetal growth and development. Maternal overt hypothyroidism and hyperthyroidism are associated with low birth weight but there are still important knowledge gaps regarding the impact of subclinical thyroid function test abnormalities on birth weight, in general or during the late second and third trimester of pregnancy, remains unknown. The aim of this study was to examine associations of maternal thyroid function with birth weight. METHODS: For this individual-participant data meta-analysis we searched Medline (Ovid), Embase.com, Web-of-Science, Cochrane CENTRAL and Google Scholar from inception to March 18(th) 2018, and published open invitations to join the Consortium on Thyroid and Pregnancy, to identify prospective cohort studies with data on maternal thyroid function during pregnancy and birth weight. We excluded participants with multiple pregnancies, in vitro fertilization, pre-existing thyroid disease or thyroid medication usage, miscarriages and stillbirth. Main outcomes were small for gestational age (SGA), large for gestational age (LGA) (defined by the lowest or highest 10(th) population-specific percentile of birth weight standardized to gestational age and sex, respectively) and birth weight. We analysed individual participant data using mixed-effects regression models adjusting for maternal age, body mass index, ethnicity, smoking, parity, gestational age at blood sampling, fetal sex and gestational age at birth (the latter two only in case of birth weight continuously). The study protocol was pre-registered at the International Prospective Register of Systematic Reviews (PROSPERO), number CRD42016043496. RESULTS: From 2,526 published reports, 36 cohorts met the inclusion criteria and were invited to participate of which 15 agreed and after addition of 5 unpublished datasets, a total of 20 cohorts were included. After exclusions, the study population comprised 48,145 mother-child pairs of whom 1,275 (3·1%) had subclinical hypothyroidism (increased TSH with normal FT4) and 929 (2·2%) had isolated hypothyroxinaemia (decreased FT4 with normal TSH). Maternal subclinical hypothyroidism was associated with a higher risk of SGA compared to euthyroidism (11·8% vs. 10·0% respectively, adjusted risk difference 2·4% [95% CI, 0·4 to 4·8]; odds ratio (OR) 1·24 [95% CI 1·04 to 1.48], P=0·015) and lower mean birth weight (adjusted risk difference −38g [95% CI −61 to −15], P=0·001) with a higher effect estimate for measurement in the 3(rd) trimester compared with the 1(st) or 2(nd) trimester. Isolated hypothyroxinaemia was associated with a lower risk of SGA compared to euthyroidism (7·3% vs. 10·0%, adjusted risk difference −2·9 [95% CI, −4·5 to −0·9]; OR, 0·70 [95% CI 0·55 to 0·91], P=0·007) and higher mean birth weight (difference, 45g [95% CI 18 to 73], P=0·001). Each 1-SD higher maternal TSH concentration was associated with lower birth weight (−6g [−10 to −2], per SD, P=0·003), with higher effect estimates in TPOAb-positive than TPO-negative women (P for interaction=0·10). Each 1-SD higher FT4 concentration was associated with lower birth weight (−21g [95% CI −25 to −17] per SD, P

Well-differentiated thyroid carcinoma (WDTC) generally has a favorable prognosis. However, patients with distant metastatic disease experience progression of disease with a higher mortality. A subset of patients not previously described may challenge the conventional dogma regarding the progressive nature of all metastatic WDTC. Through analysis of our database, we identified patients with distant metastatic WDTC and persistent, minimally progressive disease. In all patients, persistent metastatic disease was confirmed via tissue biopsy, abnormal PET scan, and/or biochemical elevations in thyroglobulin or antibody levels. Progression of disease was monitored clinically and with repeat imaging. We describe five patients with WDTC and pulmonary metastases, aged 8–43 years at diagnosis. All patients underwent initial surgery and radioactive iodine (RAI) ablation, with some receiving multiple treatments. Persistent pulmonary metastatic disease was confirmed over decades (mean 22 years, range 8–42 years) with minimal progression despite no further treatment beyond thyroid hormone suppression. Persistent disease was biopsy-proven in all patients at a mean of 9.6 years from last RAI treatment. All patients had elevated thyroglobulin or anti-thyroglobulin antibody levels, while three demonstrated metabolically active disease with positive FDG uptake on PET scan, and one patient with persistent radioactive iodine avid pulmonary metastasis 36 years after her last RAI treatment. This case series demonstrates that some patients with distant metastases, even if metabolically active and radioactive iodine resistant, remain stable for decades without further treatment. Clinical awareness of such patients and continual reassessment of disease risk following initial therapy are crucial as aggressive treatment may not be necessary.

To evaluate the characteristics of thyroid carcinoma over time, we carried out a retrospective study to illustrate the evolutionary features of thyroid carcinoma. All records of thyroidectomies from the First Affiliated Hospital of Nanjing Medical University from 2008 to 2013 were obtained focusing on pathological diagnosis, size, local lymph node metastasis (LNM) of the tumors. The thyroid cancer detection rate increased from 24.6% to 41.5% significantly (P P

Background Thyroid nodules are common, and most are benign. Given the risk of false-negative cytology (i.e. malignancy), follow-up is recommended after 1–2 years, though this recommendation is based solely on expert opinion. Sonographic appearance may assist with planning, but is limited by large inter-observer variability. We therefore compared the safety and efficacy of long- versus short-interval follow-up after a benign initial aspiration, regardless of sonographic appearance. Methods This study evaluated all patients referred to the Brigham and Women’s Hospital Thyroid Nodule Clinic, between 1999 and 2010, with a cytologically benign nodule >1 cm and who had returned for follow-up sonographic evaluation. Despite standard clinical recommendations, variation in patient compliance resulted in variable follow-up intervals from time of initial aspiration to the first repeat evaluation. Main outcome measures included nodule growth, repeat fine needle aspiration (FNA), thyroidectomy, malignancy, and disease-specific mortality. Results We evaluated 1,254 patients with 1,819 cytologically benign nodules, with a median time to first follow-up of 1.4 years (range, 0.5–14.1 years). The longer the follow-up interval, the more nodules grew and the more repeat FNAs were performed (P 3 years (4.9 % vs. 1.2 %, P = 0.0001), though no difference in malignancy risk was identified (0.2–0.8 %, P = 0.77). No (0 %) thyroid cancer-specific deaths were identified in either cohort. Conclusions While expert opinion currently recommends repeat evaluation of a cytologically benign nodule at 1–2 years, these are the first data to demonstrate that this interval can be safely extended to 3 years without increased mortality or patient harm. Nodule growth can be expected, though detection of malignancies is unchanged. While replication of these data in large prospective multicenter studies is needed, this extension in follow-up interval would reduce unnecessary visits and medical interventions for millions of affected patients worldwide, leading to healthcare savings. Please see related commentary article: http://dx.doi.org/10.1186/s12916-016-0559-9 and research article: http://dx.doi.org/10.1186/s12916-015-0419-z.

BackgroundThyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.MethodsThe specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.ResultsThe revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.ConclusionsWe have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Purpose. To determine the relationship between Hashimoto’s thyroiditis (HT) and all stages of papillary thyroid carcinoma (PTC) with or without local lymph node metastasis (LNM).Methods. We conducted a retrospective study of thyroidectomies from 2008–2013 in First Affiliated Hospital of Nanjing Medical University. We categorized patients according to the presence of histopathologically proven HT. The prevalence of mPTC (maximum diameter ≤ 10 mm) and crPTC (clinical relevant PTC) and local LNM rates were compared.Results. We evaluated 6,432 consecutive thyroidectomies. In total, 1,328 specimens were confirmed as HT. The prevalence of PTC in this HT cohort was 43.8%, significantly higher than non-HT group. After adjustment of gender and age, the prevalence of PTC was still higher in HT group. HT was a risk factor for PTC in multivariate analysis with odds ratio 2.725 (95% CI, 2.390–3.109) (P<0.001). However, no correlation was found between HT and LNM of PTC.Conclusion. HT was associated with an increased prevalence of all stages of PTC, independent of tumor size, gender, and age. In contrast, locally advanced disease defined by LNM was unrelated to HT. These data suggest an association of HT with low risk PTC and a potential protective immunologic effect from further disease progression.

Recent data suggest iodinated contrast media (ICM) exposure is associated with increased risk of incident hyperthyroidism among patients receiving care from two tertiary care medical centers. We sought to confirm and generalize these findings by conducting a case-control study among a broadly-representative community-based cohort of patients receiving care within Harvard Vanguard Medical Associates from 1996 to 2012. Incident hyperthyroid and hypothyroid cases were defined by change in thyrotropin (TSH) from normal (at baseline), to low or high (at follow-up), respectively. In parallel analyses, hyper- and hypothyroid cases were matched to euthyroid controls using incidence density sampling, and ICM exposure was ascertained using claims data. Secondary analyses examined associations with incident overt hyperthyroidism and overt hypothyroidism (follow-up TSH≤0.1 mIU/L and TSH>10 mIU/L, respectively). We observed that ICM exposure was associated with increased risk of incident hyperthyroidism [odds ratio, 1.61 (95% CI) 1.27-2.04], incident overt hyperthyroidism [odds ratio, 1.62 (95% CI) 1.08-2.43], and incident overt hypothyroidism [odds ratio 2.01 (95% CI) 1.25-3.23]. These data confirm that ICM exposure is associated with increased risk of incident thyroid functional disease in a community-based cohort of patients in an iodine-sufficient region.