Indications for treatment of subclinical hypothyroidism and isolated hypothyroxinaemia in pregnancy

Taylor, Peter; Muller, Ilaria; Nana, Melanie; Velasco, Inés; Lazarus, John

doi:10.1016/j.beem.2020.101436

Cited by 22 publications

(29 citation statements)

References 63 publications

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“…These differences of outcomes are pointing towards altered pathophysiology between SCH and IH during pregnancy. Upon meta-analysis evaluating negative outcomes of SCH, Taylor and colleagues ( 16 ) have suggested that SCH alters the metabolic environment and thus leads to adverse pregnancy complications while IH affects fetal neuronal development due to impaired fT4 availability. Animal studies support the latter by showing atypical neuronal migration and structural changes in brain regions such as somatosensory cortex and hippocampus among the offspring of rat mothers subjected to hypothyroxinemia as a result of low iodine intake ( 17 ).…”

Section: Ght Is Associated With Adverse Maternal and Fetal Outcomesmentioning

confidence: 99%

“…Arguably, some studies show SCH is also associated with lower intellectual development of the infant marked by low performance of neuropsychological and behavioral tests ( 1 , 18 , 19 ). Of note, there are lesser number of studies that examine women with IH compared to that of SCH ( 16 ). It could be because in some countries, TSH is analyzed first and only those women with TSH aberrations are next considered for analysis, there by missing a proportion of women with IH.…”

Section: Ght Is Associated With Adverse Maternal and Fetal Outcomesmentioning

confidence: 99%

“…In the light of emerging findings, a recent review by Taylor et al. ( 16 ) attempts to introduce a stepwise algorithm yet specific, when initiating the treatment for either SCH or IH during gestation. Importantly they suggest monitoring TSH and fT4 levels every 4 weeks to maintain optimal circulating concentrations of fT4 ( 16 ).…”

Section: Section 02 – Treatment Of Ght With Levothyroxine - An Ongoing Debatementioning

confidence: 99%

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Understanding the Pathogenesis of Gestational Hypothyroidism

Kankanamalage

Zhou

2021

Front. Endocrinol.

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Pregnancy is a complex state with many endocrinological challenges to a woman’s physiology. Gestational Hypothyroidism (GHT) is an emerging condition where insufficiency of the thyroid gland has developed during pregnancy in a previously euthyroid woman. It is different to overt hypothyroidism, where marked elevation of thyroid-stimulating hormone with corresponding reduction in free thyroxine levels, is well known to cause detrimental effects to both the mother and the baby. During the past couple of decades, it has been shown that GHT is associated with multiple adverse maternal and fetal outcomes such as miscarriage, pre-eclampsia, placental abruption, fetal loss, premature delivery, neurocognitive and neurobehavioral development. However, three randomized controlled trials and a prospective cohort study performed within the last decade, show that there is no neurodevelopmental improvement in the offspring of mothers who received levothyroxine treatment for GHT. Thus, the benefit of initiating treatment for GHT is highly debated within the clinical community as there may also be risks associated with over-treatment. In addition, regulatory mechanisms that could possibly lead to GHT during pregnancy are not well elucidated. This review aims to unravel pregnancy induced physiological challenges that could provide basis for the development of GHT. During pregnancy, there is increased renal clearance of iodine leading to low iodine state. Also, an elevated estrogen level leading to an increase in circulating thyroglobulin level and a decrease in free thyroxine level. Moreover, placenta secretes compounds such as human chorionic gonadotropin (hCG), placental growth factor (PIGF) and soluble FMS-like tyrosine kinase-1 (s-Flt1) that could affect the thyroid function. In turn, the passage of thyroid hormones and iodine to the fetus is highly regulated within the placental barrier. Together, these mechanisms are hypothesized to contribute to the development of intolerance of thyroid function leading to GHT in a vulnerable individual.

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Section: Ght Is Associated With Adverse Maternal and Fetal Outcomesmentioning

confidence: 99%

Section: Ght Is Associated With Adverse Maternal and Fetal Outcomesmentioning

confidence: 99%

Section: Section 02 – Treatment Of Ght With Levothyroxine - An Ongoing Debatementioning

confidence: 99%

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Understanding the Pathogenesis of Gestational Hypothyroidism

Kankanamalage

Zhou

2021

Front. Endocrinol.

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“…Regarding IH, at least two limitations occur, making this issue more difficult. The first one is that screening tests at preconception and during pregnancy do not comprise thyroxine concentration measurement [1], making a diagnosis impossible in all individuals with IH, and the second one is that statements of whether to treat or not treat pregnant patients with this kind of thyroid hypofunction are not univocal [1,[22][23][24], and regarding women planning pregnancy, this issue is not even discussed in the literature.…”

Section: Introductionmentioning

confidence: 99%

Potential Risk Factors for Isolated Hypothyroxinemia in Women of Childbearing Age—Results from Retrospective Analysis

Karbownik-Lewińska

Stępniak

Lewiński

2021

JCM

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Isolated hypothyroxinemia (IH) unfavorably affects reproduction. This study aimed to evaluate retrospectively if any routinely measured clinical/laboratory parameters are associated with IH among women of childbearing age hospitalized in the endocrine department. A group of 466 female non-pregnant inpatients (age range 13–57 years) was considered. IH (decreased free thyroxine (FT4) with normal TSH) was found in 8/466 patients (1.72%). Vitamin D deficiency (<30 ng/mL) was found in all patients with IH, whereas severe Vitamin D deficiency (<20 ng/mL) was found in 5/6. Vitamin D concentration was lower in IH females. FT4 concentration was lower in patients with severe vitamin D deficiency and correlated positively with vitamin D concentration. Insulin resistance index (IRI) was increased (>1.25) in 5/6 patients with IH. IRI was higher in IH patients and it was the only independent linear factor for IH in the univariate regression. FT4 concentration was lower in patients with increased IRI and correlated negatively with IRI. FT4 concentration correlated negatively with body mass index (BMI) and LDL cholesterol or triglycerides, and positively with HDL cholesterol or HDLC/cholesterol ratio. Vitamin D deficiency, insulin resistance and increased BMI (as potential causative factors), and abnormal lipid profile (as a possible consequence), are associated with IH in women of childbearing age. Eliminating risk factors for hypothyroxinemia may improve reproductive health.

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“…Thyroid dysfunction occurs in 5-18% of pregnant women and is associated with a higher risk of various gynecological and obstetric complications [2][3][4][5]. Pregnancy places additional demands on the thyroid gland and in about 5% of women who have checked their thyroid function during pregnancy, subclinical hypothyroidism will be found, which is unfavorable for the outcome of pregnancy and for the offspring [6]. Abalovich M. et al found that 34% of women with hypothyroidism became pregnant without treatment with Levothyroxine, with 11% having CHT and 89% SCHT [7].…”

Section: Introductionmentioning

confidence: 99%

Factors Determining Thyroid Status in Pregnant Women in Bulgaria

Borissovа¹,

Trifonova²,

Dakovska³

et al. 2020

IJDE

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Thyroid dysfunction occurs in 5-18% of pregnant women and is associated with a higher risk of various gynecological and obstetric complications and these differences are due to the specific characteristic of the study population. The aim of the present study is to analyze the population of pregnant women in Bulgaria regarding the main parameters that are relevant to their thyroid status -age, sequence of pregnancy, reproductive problems, family history of thyroid disease, body mass index. Material: We studied 547 pregnant women, mean age 30±5 years. The study was conducted as a cross-sectional multicenter population-based in 10 regions of Bulgaria or a total of 84 settlements. Methods: An individual Questionnaire was completed, determined in a central laboratory with ECLIA method TSH, FT4, TPOAb and ultrasound examination of the cervical region was conducted. Statistical processing of the material was performed using the standard SPSS 13.0 for Windows. Results: TSH levels are negatively correlated with age, P<0.07. The thyroid volume for the group of women with first pregnancy (n-245, 44.8%) is 8.67±2.23 mL, median 8.35 mL, and the thyroid volume in the remaining 302 (55.2%) women with another pregnancy is 9.15±2.85 mL, median 8.96 mL (P<0.01). Reproductive problems were reported in 119 (21.8%) pregnant women, but the correlation with TSH levels was weak, P<0.009. In 25% of women with family history of thyroid pathology there are abnormalities in thyroid function (in 96.4% hypothyroidism and in 3.6% hyperthyroidism). While in euthyroid pregnant women previous obesity was present in 8.6% (30/350), in hypothyroid pregnant women it was found in 12.7% (14/110), P<0.035. In other words, BMI before pregnancy is a significant predictor of hypothyroidism, proven during pregnancy. Conclusion: The preliminary in-depth study and presentation of the characteristics of the studied Bulgarian population of pregnant women is the basis for a proper assessment of the condition of the thyroid gland.

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Indications for treatment of subclinical hypothyroidism and isolated hypothyroxinaemia in pregnancy

Cited by 22 publications

References 63 publications

Understanding the Pathogenesis of Gestational Hypothyroidism

Understanding the Pathogenesis of Gestational Hypothyroidism

Potential Risk Factors for Isolated Hypothyroxinemia in Women of Childbearing Age—Results from Retrospective Analysis

Factors Determining Thyroid Status in Pregnant Women in Bulgaria

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