Antithyroid drug therapy in pregnancy and risk of congenital anomalies: Systematic review and meta-analysis

British Thyroid Association Survey of Graves' Disease Management in the UK

BACKGROUND

Recent years have seen changes and uncertainties in evidence and guideline recommendations in Graves' disease treatment. To understand the impact of these developments on current practice, we undertook a survey of Graves' disease management in the United Kingdom and compared this to other national and international surveys.

METHOD

Members of the British Thyroid Association, the UK Society for Endocrinology and regional endocrinology networks, were invited by e-mail to complete a 15-min online survey (October 2022 to March 2023).

RESULTS

Out of 158 eligible respondents, 99% were endocrinologists. For a 40-year-old female with a first presentation of Graves' hyperthyroidism, TSH-receptor antibodies (TRAb) were requested at diagnosis and at follow-up by 95% and 76%, respectively. Isotope scans and ultrasound were rarely requested (< 5%). Majority (95%) would treat with antithyroid drugs (ATD), predominantly Carbimazole (CMZ), while radioactive iodine (RAI) was preferred for recurrent disease (81%). Common reasons for avoiding RAI were thyroid eye disease, pregnancy intention, or contact with young children whereas biochemical severity, goitre, or male sex did not influence decision to use RAI. Propylthiouracil (PTU) was preferred in preconception and early pregnancy, but after the first-trimester, 50% would continue PTU while 50% switch back to CMZ.

CONCLUSIONS

The survey confirms a growing application of TRAbs, both for diagnostic and prognostic purposes. ATDs remain the preferred first-line therapy for Graves' disease, which is consistent with global trends but contrary to National Institute of Health and Care Excellence (NICE) guidance. Further studies are required to explore the clinical and pragmatic determinants of current treatment approaches.

Aplasia Cutis Congenita on the Scalp

Aplasia cutis congenita is a rare condition characterized by localized absent skin at birth, often affecting the scalp. The exact pathogenesis is unclear, but it is likely related to disrupted prenatal skin development. Potential etiologies include genetic factors, trauma, intrauterine infections, teratogens, incomplete neural tube closure, and vascular compromise. We present a case of aplasia cutis congenita on the scalp potentially associated with maternal methimazole use.

Identification and Characterization of Highly Potent and Isoenzyme-Selective Inhibitors of Deiodinase Type I via a Nonradioactive High-Throughput Screening Method

Objective: Deiodinase type I (DIO1) is crucial in maintaining thyroid hormone (TH) balance. It converts the prohormone thyroxine (T4) to the active triiodothyronine (T3) and degrades T3 to inactive 3,3'-diiodothyronine (3,3'-T2). It also acts on reverse T3 (rT3) and sulfated TH metabolites, thus contributing to TH elimination. Upregulation of DIO1 is linked to hyperthyroid conditions such as Graves' disease and autonomous thyroid adenoma, making it a promising target for pharmacological intervention. The adverse side effects of the antithyroid drug propylthiouracil (PTU), used in clinics to treat hyperthyroidism due to its thyroid peroxidase- and DIO1-blocking action, highlight the need for novel and potent DIO1-selective inhibitors. Methods: Using a semiautomatic high-throughput screening (HTS) assay based on the Sandell-Kolthoff (SK) reaction in 384-well plates, we screened 69,344 low-molecular-weight compounds for DIO1-inhibitory effects. Shortlisted hits underwent detailed manual characterization, where we evaluated the potency and isoenzyme specificity by assessing their DIO-inhibitory effects on enzyme preparations from all three DIO isoenzymes, over a wide concentration range (5 nM-20 µM). To evaluate the DIO1 inhibitory effects in intact cells, we applied a novel protocol based on the SK reaction to cell culture supernatants and assessed the intracellular deiodinase activity in DIO1 overexpressing HEK293 cells. Results: The robust HTS assay flagged 436 (<1%) of the screened compounds as hits, also including known DIO1 inhibitors such as PTU and genistein. Based on a validation screen of 298 compounds, we prioritized 26 compounds to comprehensively characterize their DIO1-selective inhibition. We identified 15 DIO1-selective compounds (IC50 < 1 µM), more potent than the bonafide DIO1-selective inhibitor PTU. Additionally, 8 of the 13 tested compounds were found capable of inhibiting DIO1 in intact cells. Conclusions: With a successful SK-reaction-based HTS application, we identified novel, potent, and selective inhibitors of DIO1 with nanomolar IC50 values. Furthermore, we successfully showed that some of these compounds were also capable of inhibiting intracellular DIO1 in intact cells. These novel compounds hold immense potential in studying TH modulation, deciphering DIO1 enzyme structure, and developing structure-activity relationships. Furthermore, our novel inhibitors act as lead compounds in developing strategies to combat hyperthyroidism.

Radioiodine Therapy of Graves' Disease in Women with Childbearing Potential and the Pre-Conceptional Counseling About Antithyroid Drugs

Graves' disease and hyperthyroidism in women with childbearing potential are a challenge in pre-conceptional counseling. The non-surgical alternatives are radioiodine therapy or antithyroid drugs. Here, we focus on the TSH receptor antibody (TRAb) level-without or after radioiodine therapy-and the probability of fetal or neonatal hyperthyroidism. This immunological effect should be weighed against the risk of congenital malformation taking propylthiouracil during pregnancy. For up to 2 years after radioiodine therapy for Graves' disease, TRAb levels may remain above the pre-therapeutic level. The time of conception after radioiodine therapy and a high TRAb level are associated with the likelihood of neonatal hyperthyroidism: 8.8% probability if conception occurred 6-12 months after radioiodine therapy, with a 5.5% probability for 12-18 months, and 3.6% probability for 18-24 months. The TRAb value above 10 U/L in the third trimester is the main risk factor for neonatal hyperthyroidism. If a woman does not wish to postpone her family planning, the pre-conceptional counseling has to describe the risk of propylthiouracil, thiamazole, or of an uncontrolled hyperthyroidism. According to some national cohort studies (Danish, Swedish, Korean), the risk for fetal malformations (ear, urinary tract) under propylthiouracil is increased by 1.1-1.6%, in addition to the spontaneous risk for unexposed pregnant women. For thiamazole, the additional risk for fetal malformation was about 2-3%, depending on the dose of thiamazole. Propylthiouracil has posed a lower risk for congenital malformation than an uncontrolled hyperthyroidism. To minimize the risk for the newborn, women with Graves' disease and hyperthyroidism should offer a definitive therapy strategy (e.g., radioiodine therapy) long before planning a pregnancy.

A 2023 International Survey of Clinical Practice Patterns in the Management of Graves Disease: A Decade of Change

CONTEXT

Over the past several decades, there have been indications of potential shifts in the diagnostic strategies, treatment, and monitoring of patients with Graves disease (GD).

OBJECTIVE

To evaluate current practices in managing GD and compare them to previous surveys.

METHODS

We used a global online survey of endocrinologists to assess shifts in the diagnosis, monitoring, and treatment in a typical patient with GD, as well as treatment variation in 5 different clinical scenarios.

RESULTS

A total of 1252 respondents from 85 countries completed the survey. Methods used to diagnose an uncomplicated GD case have changed over the past decade, reflecting increased use of thyrotropin receptor antibody (TRAb) and reciprocal decreases in nuclear medicine studies. The preferred mode of therapy for uncomplicated GD was antithyroid drugs (ATDs) by 91.5% of respondents, radioactive iodine (RAI) therapy by 7%, and thyroidectomy by 1.5%. Compared with previous surveys, the use of RAI as a first-line choice decreased in all geographic regions. The United States had the sharpest decline in the selection of initial therapy with RAI, decreasing from 69% in 1990 to 11.1% in 2023. In patients with persistent TRAb positivity after 18 months, 68.7% of respondents would continue the use of ATDs. After a relapse of GD, resumption of ATDs was selected by 59.9% of respondents. In patients with active thyroid eye disease or planning pregnancy, ATDs were the first choice (67.5% and 72.8%, respectively), and thyroidectomy emerged as the second choice (22.9% and 15.6%, respectively).

CONCLUSION

Paradigm shifts have occurred in the management of uncomplicated GD and its variants, as well as the response to persistent and recurrent hyperthyroidism.

Preconceptional Counseling in Women with Hyperthyroidism

Preconception evaluation of couples wishing to conceive is an important step toward a healthy pregnancy and it is especially important in people with a chronic condition or at genetic risk. The most common endocrine disorders in women at reproductive age are those involving the thyroid gland and it is well recognized that hyperthyroidism (HT), over-function of the thyroid gland, is associated with risks of maternal, fetal, and neonatal complications. The aim of this paper is to review the latest evidence regarding the components of preconception counseling in women with HT that contemplate a pregnancy. We also want to raise awareness among healthcare professionals about the importance of periconceptional counseling in improving pregnancy outcomes and avoid maternal and fetal complications related to thyroid dysfunction. In women with Graves' disease seeking pregnancy, it is essential to discuss all the treatment options along with the associated risks and benefits. Extensive prospective studies are still needed to understand the implications of current recommended strategies for the management of HT in preconception and during pregnancy.

Prevalence and associated factors of structural congenital anomalies in resource limited setting, 2023: a systematic review and meta-analysis

Background

Several studies have been conducted on structural congenital anomalies (CA). However, there is a paucity of studies that provide a comprehensive review of structural anomalies. We aimed to verify the available research articles to pool the possible risk factors of structural CA in resource-limited settings.

Setting

The research articles were genuinely searched using PubMed, Scopus, Cochrane Library, Web of Science, free Google database search engines, Google Scholar, and ScienceDirect databases. Published studies were searched and screened for inclusion in the final analysis, and studies without sound methodologies and review and meta-analysis were not included in the analysis.

Participants

This review analyzed data from 95,755 women who gave birth as reported by primary studies. Ten articles were included in this systematic review and meta-analysis. The articles that had incomplete information and case reports were excluded from the study.

Results

The overall pooled effect estimate (EI) of structural CA was 5.50 (4.88-6.12) per 100 births. In this systematic review and meta-analysis, maternal illness EI with odds ratio (OR) = 4.93 (95% CI: 1.02-8.85), unidentified drug use with OR = 2.83 (95% CI: 1.19-4.46), birth weight with OR = 4.20 (95% CI: 2.12-6.28), chewing chat with OR = 3.73 (95% CI: 1.20-6.30), chemical exposure with OR = 4.27 (95% CI: 1.19-8.44), and taking folic acid tablet during pregnancy with OR = 6.01 (95% CI: 2.87-14.89) were statistically significant in this meta-regression.

Conclusions

The overall pooled effect estimate of structural CA in a resource-limited setting was high compared to that in countries with better resources. Maternal illness, unidentified drug use, birth weight, chewing chat, chemical exposure, and never using folic acid were found to be statistically significant variables in the meta-regression. Preconception care and adequate intake of folic acid before and during early pregnancy should be advised.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022384838.

Preconception Management of Hyperthyroidism and Thyroid Status in Subsequent Pregnancy: A Population-Based Cohort Study

CONTEXT

Optimal thyroid status in pregnancy is essential in reducing the risk of adverse outcomes. The management of hyperthyroidism in women of reproductive age poses unique challenges and it is unclear how preconception treatment strategies impact on thyroid status in subsequent pregnancy.

OBJECTIVE

We aimed to determine trends in the management of hyperthyroidism before and during pregnancy and to assess the impact of different preconception treatment strategies on maternal thyroid status.

METHODS

We utilized the Clinical Practice Research Datalink database to evaluate all females aged 15-45 years with a clinical diagnosis of hyperthyroidism and a subsequent pregnancy (January 2000 to December 2017). We compared thyroid status in pregnancy according to preconception treatment, namely, (1) antithyroid drugs up to or beyond pregnancy onset, (2) definitive treatment with thyroidectomy or radioiodine before pregnancy, and (3) no treatment at pregnancy onset.

RESULTS

Our study cohort comprised 4712 pregnancies. Thyrotropin (TSH) was measured in only 53.1% of pregnancies, of which 28.1% showed suboptimal thyroid status (TSH >4.0 mU/L or TSH <0.1 mU/L plus FT4 >reference range). Pregnancies with prior definitive treatment were more likely to have suboptimal thyroid status compared with pregnancies starting during antithyroid drug treatment (odds ratio 4.72, 95% CI 3.50-6.36). A steady decline in the use of definitive treatment before pregnancy was observed from 2000 to 2017. One-third (32.6%) of first trimester carbimazole-exposed pregnancies were switched to propylthiouracil while 6.0% of propylthiouracil-exposed pregnancies switched to carbimazole.

CONCLUSION

The management of women with hyperthyroidism who become pregnant is suboptimal, particularly in those with preconception definitive treatment, and needs urgent improvement. Better thyroid monitoring and prenatal counseling are needed to optimize thyroid status, reduce teratogenic drug exposure, and ultimately reduce the risk of adverse pregnancy outcomes.

Structural congenital anomalies in resource limited setting, 2023: A systematic review and meta-analysis

BACKGROUND

A number of studies have looked at neonatal structural birth defects. However, there is no study with a comprehensive review of structural anomalies. Therefor we aimed to verify the best available articles to pool possible risk factors of structural congenital anomalies in resource limited settings.

SETTING

Genuine search of the research articles was done via PubMed, Scopes, Cochrane library, the Web of Science; free Google database search engines, Google Scholar, and Science Direct databases. Published and unpublished articles were searched and screened for inclusion in the final analysis and Studies without sound methodologies, and review and meta-analysis were not included in this analysis.

PARTICIPANTS

This review analyzed data from 95,755 women who have birthed from as reported by primary studies. Ten articles were included in this systematic review and meta-analysis. Articles which have no full information important for the analysis and case reports were excluded from the study.

RESULTS

The overall pooled effect estimate of structural congenital anomalies was 5.50 [4.88-6.12]. In this systematic review and meta-analysis maternal illness effect estimate (EI) with odds ratio (OR) = 4.93 (95%CI 1.02-8.85), unidentified drug use OR = 2.83 (95%CI 1.19-4.46), birth weight OR = 4.20 (95%CI 2.12-6.28), chewing chat OR = 3.73 (95%CI 1.20-6.30), chemical exposure OR = 4.27 (95%CI 1.19-8.44) and taking folic acid tablet during pregnancy OR = 6.01 (95%CI 2.87-14.89) were statistically significant in this meta-regression.

CONCLUSIONS

The overall pooled effect estimate of structural congenital anomalies in a resource limited setting was high compared to better resource countries. On the Meta-regression maternal illness, unidentified drug use, birth weight, chewing chat, chemical exposure and never using folic acid were found to be statistically significant variables Preconception care and adequate intake of folic acid before and during early pregnancy should be advised.

Effects of Methimazole vs Propylthiouracil in Newborns: A Comparative Review

Hyperthyroidism is more common in women and the sensitivity of thyroid function changes during pregnancy. Excess levels of thyroid hormones and thioamides have a major impact on maternal and fetal outcomes. Our aim was to perform an extensive literature review and provide relevant details concerning the analytical and clinical aspects of the potential effects of the two main drugs used (methimazole and propylthiouracil) in newborns. A thorough literature review was conducted using PubMed and Google Scholar databases. In total, 10 relevant studies were identified and data from these studies were extracted and then extrapolated into results after analysis. Three out of four studies that used methimazole and carbimazole, one and two, respectively, showed adverse fetal outcomes requiring surgical management for congenital anomalies like aplasia cutis, patent vitellointestinal duct, and gastroschisis. Out of the three studies that used propylthiouracil, one baby underwent surgery for bilateral pyelectasis, vesicovaginal fistula, anal stenosis, and polydactyly. The findings of the aforementioned studies provide enough evidence to imply that the use of methimazole and carbimazole to treat antenatal hyperthyroidism has worse fetal outcomes than the use of propylthiouracil. Also, given the paucity of data in the existing literature regarding propylthiouracil's effects on newborns, further studies in this demographic are needed.

Hyperthyroidism: aetiology, pathogenesis, diagnosis, management, complications, and prognosis

Hyperthyroidism is a common condition with a global prevalence of 0·2-1·3%. When clinical suspicion of hyperthyroidism arises, it should be confirmed by biochemical tests (eg, low TSH, high free thyroxine [FT4], or high free tri-iodothyonine [FT3]). If hyperthyroidism is confirmed by biochemical tests, a nosological diagnosis should be done to find out which disease is causing the hyperthyroidism. Helpful tools are TSH-receptor antibodies, thyroid peroxidase antibodies, thyroid ultrasonography, and scintigraphy. Hyperthyroidism is mostly caused by Graves' hyperthyroidism (70%) or toxic nodular goitre (16%). Hyperthyroidism can also be caused by subacute granulomatous thyroiditis (3%) and drugs (9%) such as amiodarone, tyrosine kinase inhibitors, and immune checkpoint inhibitors. Disease-specific recommendations are given. Currently, Graves' hyperthyroidism is preferably treated with antithyroid drugs. However, recurrence of hyperthyroidism after a 12-18 month course of antithyroid drugs occurs in approximately 50% of patients. Being younger than 40 years, having FT4 concentrations that are 40 pmol/L or higher, having TSH-binding inhibitory immunoglobulins that are higher than 6 U/L, and having a goitre size that is equivalent to or larger than WHO grade 2 before the start of treatment with antithyroid drugs increase risk of recurrence. Long-term treatment with antithyroid drugs (ie, 5-10 years of treatment) is feasible and associated with fewer recurrences (15%) than short-term treatment (ie, 12-18 months of treatment). Toxic nodular goitre is mostly treated with radioiodine (131I) or thyroidectomy and is rarely treated with radiofrequency ablation. Destructive thyrotoxicosis is usually mild and transient, requiring steroids only in severe cases. Specific attention is given to patients with hyperthyroidism who are pregnant, have COVID-19, or have other complications (eg, atrial fibrillation, thyrotoxic periodic paralysis, and thyroid storm). Hyperthyroidism is associated with increased mortality. Prognosis might be improved by rapid and sustained control of hyperthyroidism. Innovative new treatments are expected for Graves' disease, by targeting B cells or TSH receptors.