isolated hypothyroxinemia

OBJECTIVE: Iodine is essential in thyroid hormone production. Iodine deficiency is associated with serious complications (i.e miscarriage and stillbirth), whereas excess can cause thyroid dysfunction (i.e hyperthyroidism, hypothyroidism, thyroid autoimmunity). We conducted this scientometric study to visualize hot spots and trends in iodine-induced thyroid dysfunction over past two decades. The aim of this paper was to help scholars quickly understand the development and potential trend in this field, and guide future research directions...

CONTEXT: Guidelines recommend use of population- and trimester-specific TSH and FT4 reference intervals (RIs) in pregnancy. Since these are often unavailable, clinicians frequently rely on alternative diagnostic strategies. We sought to quantify the diagnostic consequences of current recommendations. METHODS: We included cohorts participating in the Consortium on Thyroid and Pregnancy. Different approaches were used to define RIs: a TSH fixed upper limit of 4.0 mU/L (fixed limit approach), a fixed subtraction from the upper limit for TSH of 0...

OBJECTIVE: Thyroid function test abnormalities are frequent and associated with the offspring's adverse neurodevelopment. This study aimed to examine the relationship between maternal thyroid function test abnormalities before 20 gestational weeks and children's cognitive, emotional and behavioural development at 3-6 years of age. PATIENTS AND MEASUREMENTS: A total of 2243 mother-child pairs were included in the final analysis. Maternal thyroid function was evaluated retrospectively during the children's preschool period...

OBJECTIVE: To assess the iodine status and its associations with thyroid function in pregnant women of Shanghai. METHODS: In this cross-sectional study, a total of 562 pregnant women were enrolled from January to December 2021. Both serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid peroxidase antibody (TPOAB), thyroglobulin antibody (TGAB), and urinary iodine concentration (UIC) were detected. Participants were divided into four groups based on their UIC values...

This scoping review critically discusses the publications of the last 30 years on the impact of mild to moderate iodine deficiency and the additional impact of endocrine disrupters during pregnancy on embryonal/fetal brain development. An asymptomatic mild to moderate iodine deficiency and/or isolated maternal hypothyroxinemia might affect the development of the embryonal/fetal brain. There is sufficient evidence underlining the importance of an adequate iodine supply for all women of childbearing age in order to prevent negative mental and social consequences for their children...

CONTEXT: Isolated hypothyroxinemia (low maternal free thyroxine [FT4] in the absence of thyroid-stimulating hormone [TSH] elevation) and subclinical hypothyroidism (high TSH in the absence of FT4 elevation) during early pregnancy are common. However, there are limited data regarding pregnancy outcomes, particularly their association with birthweight. OBJECTIVE: We assessed the association between isolated hypothyroxinemia and subclinical hypothyroidism during the first trimester and birthweight...

To study the effects of third trimester maternal isolated hypothyroxinemia (serum low free thyroxine and normal thyroid stimulating hormone level) on pregnancy outcomes, we performed a retrospective cohort study in women with singleton pregnancy between February 2009 and June 2012. Pregnant women were assigned to two groups, a hypothyroxinemia group (with maternal isolated hypothyroxinemia in the third trimester and normal thyroid function in the first and second trimesters) and a control group (with normal serum thyroid functions)...

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...

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BACKGROUND: The relationship between isolated hypothyroxinemia (IH) in pregnancy and adverse pregnancy outcomes is controversial, with no consensus on the need for treatment. METHODS: We conducted a systematic review and meta-analysis examining adverse pregnancy and neonatal outcomes in women with isolated hypothyroxinemia (IH) in pregnancy. We searched PubMed, Embase, Web of Science and the Cochrane Central Register of Controlled Trials for publications from inception to December 2022...

An insulin regimen may be necessary for about 30% of the patients with gestational diabetes mellitus (GDM). We aimed to investigate the association of free T4(fT4) levels with insulin requirement in pregnant women with GDM. We included pregnant women whose TSH levels were within the normal range and who were diagnosed with GDM, and excluded patients with thyroid dysfunction, chronic illnesses, or any previous history of antithyroid medication, levothyroxine or antidiabetic medication use. The diagnosis and treatment of GDM were based on American Diabetes Association guidelines...

BACKGROUND: Thyroid function is widely considered a lipid metabolism regulator. However, studies on lipid metabolism in pregnant women with low free thyroxine (FT4 ) levels are limited and inconclusive. Furthermore, the association between maternal FT4  deficiency and adverse lipid metabolic parameters is unknown. Therefore, we aimed to investigate this association and the effects of levothyroxine (L-T4 ) treatment on these metabolic indicators. METHODS: This retrospective study included 164 patients with isolated hypothyroidism (IH) (FT4  levels below the 5th  percentile with normal thyroid stimulating hormone levels according to the gestational-specific reference range) and 407 euthyroidism patients (control group who had regular antenatal examinations at Zhejiang Provincial People's Hospital, Hangzhou, China) between January 1, 2019, and December 31, 2020...

BACKGROUND: The association between isolated maternal hypothyroxinemia (IMH) and adverse pregnancy outcomes is still controversial. This study aimed to evaluate the association between IMH during the first trimester and adverse pregnancy outcomes in southern Chinese women. METHODS: This was a hospital-based, retrospective cohort study. The records of 7051 women, including 1337 IMH women and 5714 euthyroid women who had a singleton pregnancy and accepted routine prenatal service at the Third Affiliated Hospital of Sun Yat-Sen University from January 2015 to September 2018, were extracted from the electronic medical records system in this study...

Recently proposed concepts regarding the nature and assessment of the thyroid state have provided a model more consistent with empiric evidence. It now appears likely that there are no such entities as thyroid set points and individual euthyroidism. Rather than there being discrete thyroid states, peripheral organ parameters are associated with thyroid function in a continuous manner. Thyroid hormone levels and, in particular, levels of free thyroxine now appear to be superior to thyrotropin levels as indicators of the thyroid state...

Objectives: Adequate maternal thyroid hormone availability is crucial for fetal neurodevelopment, but the role of maternal mild hypothyroidism is not clear. We aim to investigate the association of maternal mild hypothyroidism with neurodevelopment in infants at 1 year of age among TPOAb-negative women. Methods: The present study was conducted within the Jiangsu Birth Cohort. A total of 793 mother-infant pairs were eligible for the present study. Maternal thyroid function was assessed by measuring serum thyroid-stimulating hormone, free thyroxine, and thyroid peroxidase antibodies...

Objective: We aimed to determine the association between maternal characteristics and isolated maternal hypothyroxinemia (IMH). Methods: Pregnancies registered at Shanghai First Maternity and Infant Hospital between January 2014 and September 2020 were included in this cross-sectional study. IMH was defined as free thyroxine (FT4) levels below the 10th percentile with TSH within the normal reference range. Multivariate logistic regression models were used to identify potential risk factors for IMH, including demographic information, anthropometric measurements and nutritional status...

Southern Xinjiang has a history of serious iodine deficiency. Since 2007, pregnant women in this area have taken iodized salt and oral lipiodol preparations to prevent iodine deficiency disorders. However, the current status of iodine nutrition and thyroid function in this population is unknown. A cross-sectional study was conducted on 555 pregnant women from 5 counties (cities) in southern Xinjiang and 429 pregnant women from 3 counties in northern Xinjiang. The participants were given a questionnaire and serum concentrations of free triiodothyronine (FT3), free thyroxine (FT4), thyrotropic stimulating hormone (TSH), thyroglobulin antibody (Tg-Ab), and thyroid peroxidase antibody (TPO-Ab), and the urine iodine concentration (UIC) was measured...

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...

OBJECTIVE:  Thyroid diseases are the second most common endocrine disorders in the reproductive period of women. They can be associated with intrauterine growth restriction (IUGR), preterm delivery, low Apgar score, low birthweight (LBW) or fetal death. The aim of the present study is to explore thyroid dysfunction and its relationship with some poor perinatal outcomes (Apgar Score, low birthweight, and preterm delivery). METHODS:  Dried blood spot samples from 358 healthy pregnant women were analyzed for thyroid stimulating hormone (TSH), total thyroxine (TT4), and thyroglobulin (Tg)...

Isolated maternal hypothyroxinemia (IMH) is defined as the presence of low maternal total thyroxine (TT4) level in conjunction with normal maternal thyroid-stimulating hormone (TSH) level. The aim was to investigate whether IMH is associated with adverse pregnancy outcome in North Macedonia. Dried blood spot samples were obtained from 359 pregnant women meeting the inclusion criteria and analyzed for TT4 and TSH. Postpartum data were entered from their medical histories. Out of 359 women, 131 (37.42%) belonged to IMH group...