Effects of Levothyroxine on Pregnant Women With Subclinical Hypothyroidism, Negative for Thyroid Peroxidase Antibodies

Nazarpour, Sima; Tehrani, Fahimeh Ramezani; Simbar, Masoumeh; Tohidi, Maryam; Minooee, Sonia; Rahmati, Maryam; Azizi, Fereidoun

doi:10.1210/jc.2017-01850

Cited by 116 publications

(100 citation statements)

References 29 publications

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“…12 A subsequent study from the same group failed to show any levothyroxine treatment difference in preterm delivery in anti-TPO negative women when a TSH cut-off of 2.5 mU/L was applied, but there was a reduction using a TSH cut-off of 4.0 mU/L. 13 A retrospective analysis of a large US administrative claims database showed that pregnant women with subclinical hypothyroidism treated with levothyroxine had reduced pregnancy loss compared to untreated women, but only in those with pre-treatment TSH concentration of 4.1-10 mU/L. 14 Limitations of this study included the retrospective observational design, potential for misclassification, selection bias and other confounders. A recent systematic review involving 3995 pregnant women supported an association between subclinical hypothyroidism and adverse maternal and neonatal outcomes; however, this association may not be causal and may be overestimated by publication bias.…”

Section: Subclinical Hypothyroidism In Pregnancymentioning

confidence: 98%

“…A further study of anti‐TPO positive women with TSH >2.5 mU/L treated with levothyroxine before 14 weeks’ gestation also found a reduced risk of pre‐term delivery, but mainly in those with TSH >4.0 mU/L . A subsequent study from the same group failed to show any levothyroxine treatment difference in pre‐term delivery in anti‐TPO negative women when a TSH cut‐off of 2.5 mU/L was applied, but there was a reduction using a TSH cut‐off of 4.0 mU/L . A retrospective analysis of a large US administrative claims database showed that pregnant women with subclinical hypothyroidism treated with levothyroxine had reduced pregnancy loss compared to untreated women, but only in those with pre‐treatment TSH concentration of 4.1–10 mU/L .…”

Section: Introductionmentioning

confidence: 99%

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Subclinical hypothyroidism during pregnancy: the Melbourne public hospitals consensus

Hamblin

Sheehan

Allan

et al. 2019

Internal Medicine Journal

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Background Interest in potential adverse outcomes associated with maternal subclinical hypothyroidism (normal free T4, elevated thyroid‐stimulating hormone (TSH)) has increased significantly over recent years. In turn, the frequency of maternal thyroid function testing has risen, despite universal thyroid function screening not being recommended, leading to a marked increase in referrals to obstetric endocrinology clinics. In 2017 the American Thyroid Association revised their diagnostic and management guidelines. Although welcome, these new guidelines contain recommendations that may cause confusion in clinical practice. Aim To ensure uniform practice in the diagnosis and management of subclinical hypothyroidism in pregnancy across all Melbourne public hospitals. Methods Endocrinology and obstetric representatives from all Melbourne public hospital networks reviewed the 2017 American Thyroid Association guidelines and other relevant literature to develop a consensus for diagnosing and treating subclinical hypothyroidism during pregnancy in Melbourne. The consensus guidelines were then referred to the Endocrine Society of Australia for comment and endorsement. Results Consensus was achieved and the guidelines were endorsed by the Council of the Endocrine Society of Australia. Trimester and assay‐specific TSH reference intervals derived from healthy local populations should be used, where available. When unavailable, a TSH cut‐off of 4 mU/L (replacing the previously recommended 2.5 mU/L) should be used to initiate treatment, irrespective of thyroid auto‐antibody status. The recommended starting dose of levothyroxine is 50 μg daily, with a therapeutic TSH target of 0.1–2.5 mU/L. Levothyroxine should generally be ceased after delivery, with some exceptions. Hospitals will ensure smooth transfer of care back to the woman’s general practitioner with clear documentation of pregnancy thyroid management and a recommended plan for follow‐up. Conclusion Fewer women will be classified as having subclinical hypothyroidism during pregnancy, which is likely to lead to reductions in emotional stress, hospital visits, repeated blood tests and financial costs. Uniform clinical practice will occur across Melbourne.

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Section: Subclinical Hypothyroidism In Pregnancymentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Subclinical hypothyroidism during pregnancy: the Melbourne public hospitals consensus

Hamblin

Sheehan

Allan

et al. 2019

Internal Medicine Journal

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“…Zhao et al reported an overall reduction in pregnancy complication rate in women treated in the first trimester, but not in those treated in the second trimester (22). Similarly, the randomized controlled trial by Nazarpour et al initiated treatment soon after the first prenatal visit, and found a reduction in the rate of preterm delivery in treated women (23).…”

Section: C) Treatment Of Subclinical Hypothyroidism (Question 37)mentioning

confidence: 99%

“…and (Recommendation 29) LT4 therapy is recommended for TPOAb-positive women with elevated TSH and TPOAb-negative women with a TSH >10.0 mIU/L; LT4 therapy may be considered for TPOAb-positive women with TSH >2.5 mIU/L or TPOAb-negative women with elevated TSH; LT4 therapy is not recommended in TPOAb-negative women with normal TSH Five studies published since the 2017 ATA Guidelines addressed the treatment of subclinical hypothyroidism in pregnancy (22)(23)(24)(25)(26). Two studies reported a decrease in negative perinatal outcomes in women who were treated (22,23). In a prospective study of 93 women with subclinical hypothyroidism, defined as TSH above 2.5 mIU/L in the first trimester or above 3.0 mIU/L in the second trimester, Zhao et al 22 (23).…”

Section: C) Treatment Of Subclinical Hypothyroidism (Question 37)mentioning

confidence: 99%

“…Two studies reported a decrease in negative perinatal outcomes in women who were treated (22,23). In a prospective study of 93 women with subclinical hypothyroidism, defined as TSH above 2.5 mIU/L in the first trimester or above 3.0 mIU/L in the second trimester, Zhao et al 22 (23). Two studies reported no benefit of treatment (24,25).…”

Section: C) Treatment Of Subclinical Hypothyroidism (Question 37)mentioning

confidence: 99%

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The Need for Dynamic Clinical Guidelines: A Systematic Review of New Research Published After Release of the 2017 ATA Guidelines on Thyroid Disease During Pregnancy and the Postpartum

2020

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Background: The American Thyroid Association Guidelines on Thyroid Disease During Pregnancy and the Postpartum (ATA Guidelines) were published in 2017, with an update not expected for another 5 years. Since release of the 2017 ATA Guidelines, greater than 500 articles have been published in the field. Furthermore, there are presently 14 prospective, interventional trials in progress registered at Clinicaltrials.gov Static guidelines updated every 5-7 years fail to provide timely evidence-based guidance to practicing clinicians. Consequently, guideline development should move toward the creation of dynamic documents. The present article reviews the literature published since the 2017 ATA Guidelines, both to benefit clinicians in practice and to make the case for Dynamic ATA Guidelines. Methods: Using the search terms "thyroid" and "pregnancy," a systematic review of literature published in Pubmed from 3/1/2017 to 12/31/2018 was conducted. The titles and/or abstracts of all articles were reviewed. All articles were classified by subject headings used in the 2017 ATA Guidelines. English-text articles classified under "hypothyroidism" or "thyroid autoimmunity" were examined in full-text. Using the questions and recommendations put forth by the previous ATA Guidelines, relevant articles were selected for discussion in this review. Results: At the time of the search, 659 unique articles on "thyroid and pregnancy" were identified, including 66 original studies on hypothyroidism and 26 on thyroid autoimmunity. Of these, 26 studies on hypothyroidism and 18 studies on thyroid autoimmunity were selected for inclusion in this review based on specific questions in the 2017 ATA Guidelines. Based on these 44 articles, we propose two specific changes to the 2017 ATA Guidelines. Conclusion: Based on new research, we recommend the 2017 ATA Guidelines be updated to recommend against treating thyroid antibody-negative women diagnosed Dong et al. Thyroid in Pregnancy Since 2017 with subclinical hypothyroidism in the second trimester or later; to reflect new, moderate-quality evidence supporting the treatment of thyroid peroxidase antibody-negative women with elevated thyroid stimulating hormone levels in the first trimester or earlier; and to recommend against treatment of euthyroid, thyroid peroxidase antibody-positive women undergoing assisted reproductive technology. Transitioning to a Dynamic ATA Guidelines would allow for these and future recommendations to be implemented in real time.

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Preconception Thyrotropin Levels and Risk of Adverse Pregnancy Outcomes in Chinese Women Aged 20 to 49 Years

Yang

Guo

et al. 2021

JAMA Netw Open

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Key Points Question Are abnormal preconception thyrotropin levels associated with adverse maternal and fetal outcomes? Findings In this populational-based cohort study of over 5.8 million Chinese women, both low and high maternal preconception thyrotropin levels were associated with higher risk of preterm birth, small for gestational age, and perinatal infant death. Meaning In this study, both low and high maternal thyrotropin levels were associated with a significantly increased risk of adverse pregnancy outcomes; the optimal preconception thyrotropin levels may be between 0.37 mIU/L and 2.50 mIU/L.

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Effects of Levothyroxine on Pregnant Women With Subclinical Hypothyroidism, Negative for Thyroid Peroxidase Antibodies

Abstract: Despite no beneficial effect of LT4 therapy in reducing preterm delivery in SCH-TPOAb- women with a TSH cut point of 2.5 to 4 mIU/L, LT4 could precisely decrease this complication using the newly recommended cutoff ≥4.0 mIU/L.

Cited by 116 publications

References 29 publications

Subclinical hypothyroidism during pregnancy: the Melbourne public hospitals consensus

Subclinical hypothyroidism during pregnancy: the Melbourne public hospitals consensus

The Need for Dynamic Clinical Guidelines: A Systematic Review of New Research Published After Release of the 2017 ATA Guidelines on Thyroid Disease During Pregnancy and the Postpartum

Preconception Thyrotropin Levels and Risk of Adverse Pregnancy Outcomes in Chinese Women Aged 20 to 49 Years

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