Thyroxine pregnancy subclinical hypothyroidism,iodine

OBJECTIVE:  Our objective was to evaluate whether iodine status in pregnant patients with either subclinical hypothyroidism or hypothyroxinemia in the first half of pregnancy is associated with measures of behavior and neurodevelopment in children through the age of 5 years. STUDY DESIGN:  This is a secondary analysis of a multicenter study consisting of two randomized, double-masked, placebo-controlled treatment trials conducted in parallel. Patients with a singleton gestation before 20 weeks' gestation underwent thyroid screening using serum thyrotropin and free thyroxine...

CONTEXT: Hysterosalpingography (HSG) with oil-soluble contrast medium (OSCM) improves pregnancy rates. However, OSCM has high iodine content and long half-life, leading to potential iodine excess. OBJECTIVE: This work aimed to determine the pattern of iodine excess after OSCM HSG and the effect on thyroid function. METHODS: A prospective cohort study was conducted of 196 consecutive consenting eligible women without overt hypothyroidism or hyperthyroidism...

Hypothyroidism is the common clinical condition of thyroid hormone deficiency and, if left untreated, can lead to serious adverse health effects on multiple organ systems, with the cardiovascular system as the most robustly studied target. Overt primary hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) concentration in combination with free thyroxine (fT4 ) concentration below the reference range. Subclinical hypothyroidism, commonly considered an early sign of thyroid failure, is defined by elevated TSH concentrations but fT4 concentrations within the reference range...

OBJECTIVE: To investigate iodine status among pregnant women in an iodine-sufficient region in China after the implementation of revised universal salt iodization (USI) standards in 2012 and assess the association between urinary iodine concentrations (UIC) in early pregnancy and the incidence of subclinical hypothyroidism (SCH) in euthyroid women negative for antithyroid Ab during different trimesters. METHODS: We measured the iodine status of 1,264 pregnant women, and performed follow-up assessment of thyroid function at 20 and 30 weeks of gestation among a cohort of 250 euthyroid women...

Background: Studies assessing thyroid hormones in metabolic syndrome (MetS) patients are contradictory. Also, the effect of MetS on thyroid function over time is not yet evaluated. This study investigated the prevalence and incidence of thyroid dysfunction (TD) as well as time trends of thyroid hormones in subjects with and without MetS, during a 10-year follow-up in Tehranian adult population. Methods: This is a prospective cohort study conducted in the framework of Tehran Thyroid Study on 5,786 subjects aged ≥20 years: 4,905 eligible participants entered the study after excluding those with corticosteroid or radioactive iodine use, pregnancy, thyrotropin (TSH) <0...

Context: Ethnic differences in thyroid function during pregnancy have been reported. However, it is unclear if this is equally valid across ethnic groups within multiethnic populations. Objective: We aimed to assess ethnic differences in thyrotropin (TSH) and free thyroxine (FT4), and the prevalence of thyroid dysfunction and thyroid autoimmunity during pregnancy. Methods: In a population-based cohort of 785 pregnant women in Oslo, Norway, TSH, FT4, and thyroid peroxidase antibodies (TPO Abs) were measured twice: at gestational week (GW) 15 and 28, and urine iodine concentration at GW 15...

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...

BACKGROUND AND OBJECTIVES: This study was undertaken to evaluate the status of iodine nutrition and thyroid function of women at different phases of gestation in an iodine sufficient rural area. METHODS AND STUDY DESIGN: 215 pregnant women in different trimesters were consecutively enrolled in iodine sufficient rural areas of Yongjing county of Gansu province, China. The blood samples and random urine samples were collected from them, and serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxin (FT4), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb) and urinary iodine were measured...

PURPOSE: The association between iodine intake and thyroid autoimmunity has been debated, especially in pregnant women. This study aimed to investigate thyroid autoantibodies and their association with iodine intake and hypothyroidism in early pregnancy. METHODS: 7073 early pregnant women from an iodine-sufficient region participated in this study. Urinary iodine concentrations (UICs) were measured using an ammonium persulfate method. Serum thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), thyroid-stimulating hormone (TSH), free thyroxine (FT4), and Tg were determined using an electrochemiluminescence immunoassay...

OBJECTIVE: To assess iodine status and its effects on maternal thyroid function throughout pregnancy. DESIGN: In the present prospective cohort study, three urinary samples were requested for urinary iodine concentration (UIC) determinations in both the first and third gestational trimesters. Serum thyrotropin (TSH) and free thyroxine (FT4) were analysed in both trimesters and thyroid antibodies were assessed once. SETTING: Rio de Janeiro, Brazil...

OBJECTIVE: To evaluate thyroid function and iodine nutritional status for pregnant women from various regions of China by determining plasma levels of thyrotrophin( TSH), free triiodothyronine( FT3), and free thyroxine( FT4). METHODS: Plasma samples were obtained from pregnant women that participated in the 2010-2012 China National Nutrition and Health Survey. Plasma levels of TSH, FT3, and FT4 were determined by using an automated chemiluminescence immunoassay analyzer...

BACKGROUND: Thyroid dysfunction is associated with negative neonatal and obstetric outcomes. Large differences in thyroid function reference intervals exist across different populations. These differences can be explained by population-specific factors, such as iodine status. Many countries in Latin America report iodine sufficiency, but relatively few countries have published up-to-date data on iodine levels and thyroid function in the overall population, and especially in pregnant women...

BACKGROUND: Iodine deficiency, thyroid dysfunction and development of thyroid autoimmunity during pregnancy may affect mother and the developing fetus. This study was carried out to find iodine status, thyroid dysfunction and thyroid autoimmunity among pregnant women. METHODS: Ninety two pregnant women from three districts of eastern Nepal (Sunsari, Morang and Jhapa) were enrolled for the study, and urine and blood samples were collected. Urinary iodine concentration (UIC), free thyroxine (free T4), thyroid stimulating hormone (TSH), thyroglobulin and anti-thyroid peroxidase (TPO) antibody levels were estimated...

BACKGROUND: Subclinical hypothyroidism (SH) is associated with adverse obstetric outcomes and neurodevelopment disorders. Both iodine deficiency and excess are associated with SH; however, few data regarding iodine nutrition status of pregnant women with SH are available. This study aimed to clarify whether iodine deficiency or excess is associated with SH, especially, when test results for anti-thyroid autoantibodies are negative. METHODS: A total of 115 women with SH and 104 women with euthyroidism (EH) in early pregnancy in Tianjin, China were investigated, and their serum thyroid-stimulating hormone, free thyroxine, free triiodothyronine, anti-thyroid peroxidase antibody (TPOAb), anti-thyroid globulin antibody (TGAb), urinary iodine (UIC), and urinary creatinine (UCr) concentrations were measured...

Serum thyroid-stimulating hormone (TSH) testing is the best screening tool for thyroid dysfunction. When TSH levels are in the reference range, additional tests such as free thyroxine, free triiodothyronine or thyroid antibodies rarely add value, except in patients with pituitary disease, when TSH is unreliable. Overt hypothyroidism and subclinical hypothyroidism with TSH levels > 10 mU/L can be treated without further investigation. The health impact of subclinical hypothyroidism with mildly elevated levels of TSH (4-10 mU/L) remains uncertain, particularly in older people; treatment or observation are reasonable options...

While there is agreement that overt maternal hypothyroidism (serum thyroid stimulating hormone (TSH) >10 mIU/L) should be treated immediately, the evidence is mixed regarding the harm associated with subclinical hypothyroidism and the benefits of thyroxine replacement. The diagnosis of subclinical hypothyroidism rests on the recognition of an increased serum concentration of TSH which may be affected by many factors including gestational age, analytical method, the antibody status of the mother, ethnicity, iodine nutrition and even the time of day when the blood is collected...

Maternal hypothyroxinemia can induce neurodevelopmental impairments in the developing fetus. We here review recent studies on the epidemiology and molecular mechanisms associated with this important public health issue. In 2011, the American Thyroid Association defined maternal hypothyroxinemia as low serum free thyroxine (FT4) levels (<5th or <10th percentile) existing in conjunction with normal serum free triiodothyronine (FT3) or thyroid stimulating hormone (TSH) levels during pregnancy. Compared to clinical or subclinical hypothyroidism, hypothyroxinemia is more commonly found in pregnant women...

CONTEXT: The WHO Technical Consultation recommends urinary iodine concentrations (UIC) from 250 to 499 μg/L as more-than-adequate iodine intake and UIC ≥ 500 μg/L as excessive iodine for pregnant and lactating women, but scientific evidence for this is weak. OBJECTIVE: We investigated optimal and safe ranges of iodine intake during early pregnancy in an iodine-sufficient region of China. METHOD: Seven thousand one hundred ninety pregnant women at 4-8 weeks gestation were investigated and their UIC, serum thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroid-peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), and thyroglobulin (Tg) were measured...

OBJECTIVE: The effects of long-term excessive maternal iodine intake on neonatal thyroid function are less known. This study aimed to assess the effects of maternal excessive iodine intake from drinking water on thyroid functions of both mothers and their neonates. DESIGN AND METHODS: This observational study was performed in high iodine (HI) areas and adequate iodine (AI) intake areas, including 384 healthy pregnant women in late gestation (mean week 39·3 ± 1·6 weeks) and their newborns...

This guideline has been produced as the official statement of the European Thyroid Association guideline committee. Subclinical hypothyroidism (SCH) in pregnancy is defined as a thyroid-stimulating hormone (TSH) level above the pregnancy-related reference range with a normal serum thyroxine concentration. Isolated hypothyroxinaemia (defined as a thyroxine level below the 2.5th centile of the pregnancy-related reference range with a normal TSH level) is also recognized in pregnancy. In the majority of SCH the cause is autoimmune thyroiditis but may also be due to iodine deficiency...