scholarly journals Iodine Intake is Associated with Thyroid Function in Mild to Moderately Iodine Deficient Pregnant Women

Thyroid ◽  
2018 ◽  
Vol 28 (10) ◽  
pp. 1359-1371 ◽  
Author(s):  
Marianne Hope Abel ◽  
Tim I.M. Korevaar ◽  
Iris Erlund ◽  
Gro Dehli Villanger ◽  
Ida Henriette Caspersen ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Iodine Intake

scholarly journals Iodine Intake and Thyroid Function in Pregnant Women in a Private Clinical Practice in Northwestern Sydney before Mandatory Fortification of Bread with Iodised Salt

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Norman Blumenthal ◽  
Karen Byth ◽  
Creswell J. Eastman
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Iodine Deficiency ◽  
Urinary Iodine ◽  
Iodine Intake ◽  
Urinary Iodine Excretion ◽  
Blood Collection ◽  
Antenatal Visit ◽  
Urinary Iodine Concentration ◽  
Cross Sectional

Aim. The primary objective of the study was to assess the iodine nutritional status, and its effect on thyroid function, of pregnant women in a private obstetrical practice in Sydney.Methods. It was a cross-sectional study undertaken between November 2007 and March 2009. Blood samples were taken from 367 women at their first antenatal visit between 7 and 11 weeks gestation for measurement of thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels and spot urine samples for urinary iodine excretion were taken at the same time as blood collection.Results. The median urinary iodine concentration (UIC) for all women was 81 μg/l (interquartile range 41–169 μg/l). 71.9% of the women exhibited a UIC of <150 μg/l. 26% of the women had a UIC <50 μg/l, and 12% had a UIC <20 μg/l. The only detectable influences on UIC were daily milk intake and pregnancy supplements. There was no statistically significant association between UIC and thyroid function and no evidence for an effect of iodine intake on thyroid function.Conclusions. There is a high prevalence of mild to moderate iodine deficiency in women in Western Sydney but no evidence for a significant adverse effect on thyroid function. The 6.5% prevalence of subclinical hypothyroidism is unlikely to be due to iodine deficiency.

scholarly journals Perchlorate and Thiocyanate Exposure and Thyroid Function in First-Trimester Pregnant Women

2010 ◽  
Vol 95 (7) ◽  
pp. 3207-3215 ◽  
Author(s):  
Elizabeth N. Pearce ◽  
John H. Lazarus ◽  
Peter P. A. Smyth ◽  
Xuemei He ◽  
Daniela Dall'Amico ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Sodium Iodide ◽  
Urinary Iodine ◽  
First Trimester ◽  
Iodine Intake ◽  
Sodium Iodide Symporter ◽  
Free T4 ◽  
Cross Sectional ◽  
Serum Tsh

Context: Thyroid hormone, requiring adequate maternal iodine intake, is critical for fetal neurodevelopment. Perchlorate decreases thyroidal iodine uptake by competitively inhibiting the sodium/iodide symporter. It is unclear whether environmental perchlorate exposure adversely affects thyroid function in pregnant women. Thiocyanate, derived from foods and cigarette smoke, is a less potent competitive sodium/iodide symporter inhibitor than perchlorate. Objective: Our objective was to determine whether environmental perchlorate and/or thiocyanate exposure is associated with alterations in thyroid function in pregnancy. Design and Setting: We conducted a cross-sectional study at health centers in Cardiff, Wales, and Turin, Italy. Patients: During 2002–2006, 22,000 women at less than 16 wk gestation were enrolled in the Controlled Antenatal Thyroid Screening Study. Subsets of 261 hypothyroid/hypothyroxinemic and 526 euthyroid women from Turin and 374 hypothyroid/hypothyroxinemic and 480 euthyroid women from Cardiff were selected based on availability of stored urine samples and thyroid function data. Main Outcome Measures: Urinary iodine, thiocyanate, and perchlorate and serum TSH, free T4 (FT4), and thyroperoxidase antibody were measured. Results: Urinary iodine was low: median 98 μg/liter in Cardiff and 52 μg/liter in Turin. Urine perchlorate was detectable in all women. The median (range) urinary perchlorate concentration was 5 μg/liter (0.04–168 μg/liter) in Turin and 2 μg/liter (0.02–368 μg/liter) in Cardiff. There were no associations between urine perchlorate concentrations and serum TSH or FT4 in the individual euthyroid or hypothyroid/hypothyroxinemic cohorts. In multivariable linear analyses, log perchlorate was not a predictor of serum FT4 or TSH. Conclusions: Low-level perchlorate exposure is ubiquitous but did not affect thyroid function in this cohort of iodine-deficient pregnant women.

scholarly journals A Longitudinal Study of Changes in Thyroid Related Hormones among Pregnant Women Residing in an Iodine Deficient Urban Area

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Shan Elahi ◽  
Zaib Hussain
Keyword(s):  
Thyroid Gland ◽  
Pregnant Women ◽  
Urban Area ◽  
Thyroid Function ◽  
Iodine Intake ◽  
Third Trimester ◽  
Functional Changes ◽  
Gestation Time ◽  
Commercial Kits ◽  
One Way Anova

Problem Statement. Thyroid gland in women undergoes functional changes during pregnancy. A few studies have described such changes in pregnant women residing in iodine deficient areas. Objective. To document these changes in pregnant women residing in Lahore, a low iodine intake urban area of Pakistan. Patients and Methods. In 254 pregnant women, data of FT4, FT3, and TSH during the first and subsequent trimesters were obtained and compared with those of 110 nonpregnant women. These hormones were determined in serum by radioimmunoassay (RIA) techniques using commercial kits. Results. Compared to nonpregnant women mean FT4 level was decreased, and FT3 and TSH increased significantly () in pregnant women. A negative correlation of FT4 with TSH was observed in all three trimesters. Serum FT3 was positively correlated with TSH only during the third trimester. As a function of gestation time, FT4 levels progressively decreased, and FT3 and TSH levels increased significantly (one-way ANOVA = 108.2, 17.3, and 44.8, resp.; all ) exhibiting thyroid gland adaptations. Conclusion. Pregnancy is associated with significant alterations in thyroid function due to low iodine intake in women residing in study area. The compensated thyroid function poses a risk of thyroid failure in a number of pregnant women.

scholarly journals Effect of Excess Iodine Intake from Iodized Salt and/or Groundwater Iodine on Thyroid Function in Nonpregnant and Pregnant Women, Infants, and Children: A Multicenter Study in East Africa

Thyroid ◽  
2018 ◽  
Vol 28 (9) ◽  
pp. 1198-1210 ◽  
Author(s):  
Jessica Farebrother ◽  
Michael B. Zimmermann ◽  
Fatma Abdallah ◽  
Vincent Assey ◽  
Ralph Fingerhut ◽  
...  
Keyword(s):  
Pregnant Women ◽  
East Africa ◽  
Thyroid Function ◽  
Multicenter Study ◽  
Iodine Intake ◽  
Iodized Salt ◽  
Infants And Children ◽  
Excess Iodine

scholarly journals Evaluation of median urinary iodine concentration cut-off for defining iodine deficiency in pregnant women after a long term USI in China

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Huidi Zhang ◽  
Meng Wu ◽  
Lichen Yang ◽  
Jinghuan Wu ◽  
Yichun Hu ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Iodine Deficiency ◽  
Urinary Iodine ◽  
Iodine Concentration ◽  
Iodine Intake ◽  
Urinary Iodine Concentration ◽  
Normal Thyroid ◽  
Normal Thyroid Function

Abstract Background The WHO/UNICEF/ICCIDD define iodine deficiency during pregnancy as median urinary iodine concentration (MUIC) ≤ 150 μg/L. China implemented universal salt iodization (USI) in 1995, and recent surveillance showed nationwide elimination of iodine deficiency disorders (IDD). Data from 2014 showed that the MUIC in 19,500 pregnant women was 154.6 μg/L and 145 μg/L in 9000 pregnant women in 2015. However, symptoms of iodine deficiency were absent. Our study sought to evaluate whether MUIC below 150 μg/L affects thyroid function of Chinese pregnant women and their newborns in Chinese context. Methods We screened 103 women with normal thyroid function and MUIC lower than 150 μg/L during week 6 of pregnancy at Peking Union Medical College Hospital. Patient demographics and dietary salt intake were recorded. Subjects were followed at 12, 24, and 32 gestational weeks. At each visit, a 3-day dietary record, drinking water samples, and edible salt samples were collected and analyzed for total dietary iodine intake. Additionally, 24-h urine iodine and creatinine were measured. Blood tests assessed thyroid function in both mothers and newborns. Results Of 103 pregnant women enrolled, 79 completed all follow-up visits. Most subjects maintained normal thyroid function throughout pregnancy. However, 19 had thyroid dysfunction based on thyroid stimulating hormone and free thyroxine levels. The median serum iodine was 71 μg/L (95% CI: 44, 109). The median thyroglobulin was < 13 μg/L. values above this level indicate iodine deficiency in pregnant women. The median dietary iodine intake during pregnancy, derived from the 3-day record and measures of water and salt, was 231.17 μg/d. Assuming 90% urinary iodine excretion (UIE), 200.11 μg/d UIE means the 222.34 μg iodine loss per day, suggesting that subjects had a positive iodine balance throughout pregnancy. All neonatal blood samples showed TSH levels lower than 10 mIU/L, indicating normal thyroid function. No significant difference was found among gestational weeks for urinary iodine, and the MUIC in subjects who completed 3 follow-up visits was 107.41 μg/L. Conclusion Twenty years after implementing USI, expectant Chinese mothers with MUIC of 107.4 μg/L, less than the WHO’s 150 μg/L benchmark, maintained thyroid function in both themselves and their newborn babies.

Thyroid function in pregnant women; relation to Gestational Diabetes Mellitus (GDM) and Body Mass Index (BMI)

2018 ◽  
Author(s):  
George Simeakis ◽  
Evangelia Vogiatzi ◽  
Panagiota Konstantakou ◽  
Evangelia Zapanti ◽  
Katerina Saltiki ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Body Mass Index ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Pregnant Women ◽  
Body Mass ◽  
Thyroid Function

Effects of iodine excess on serum thyrotropin-releasing hormone levels and type 2 deiodinase in the hypothalamus of Wistar rats

2021 ◽  
pp. 1-30
Author(s):  
Ying Sun ◽  
Xin Du ◽  
Zhongyan Shan ◽  
Weiping Teng ◽  
Yaqiu Jiang
Keyword(s):  
Thyroid Function ◽  
Wistar Rats ◽  
Iodine Intake ◽  
Thyrotropin Releasing Hormone ◽  
High Iodine ◽  
Releasing Hormone ◽  
Iodine Excess ◽  
Excessive Iodine ◽  
Thyroid Hormone Biosynthesis

Abstract Iodine is an important element in thyroid hormone biosynthesis. Thyroid function is regulated by the hypothalamic-pituitary-thyroid axis (HPT). Excessive iodine leads to elevated thyroid stimulating hormone (TSH) levels, but the mechanism is not yet clear. Type 2 deiodinase (Dio2) is a selenium-containing protease that plays a vital role in thyroid function. The purpose of this study was to explore the role of hypothalamus Dio2 in regulating TSH increase caused by excessive iodine and to determine the effects of iodine excess on thyrotropin-releasing hormone (TRH) levels. Male Wistar rats were randomized into five groups and administered different iodine dosages (folds of physiological dose): normal iodine (NI), 3-fold iodine (3HI), 6-fold iodine (6HI), 10-fold iodine (10HI), and 50-fold iodine (50HI). Rats were euthanized at 4, 8, 12, or 24 weeks after iodine administration. Serum TRH, TSH, total thyroxine (TT4), and total triiodothyronine (TT3) were determined. Hypothalamus tissues were frozen and sectioned to evaluate expression of Dio2, Dio2 activity, and monocarboxylate transporter 8 (MCT8). Prolonged high iodine intake significantly increased TSH expression (p < 0.05), but did not affect TT3 and TT4 levels. Prolonged high iodine intake decreased serum TRH levels in the hypothalamus (p < 0.05). Dio2 expression and activity in the hypothalamus exhibited an increasing trend compared at each time point with increasing iodine intake (p < 0.05). Hypothalamic MCT8 expression was increased in rats with prolonged high iodine intake(p < 0.05). These results indicate that iodine excess affects the levels of Dio2, TRH, and MCT8 in the hypothalamus.

scholarly journals Iodine and iron status of pregnant women in Lubumbashi, Democratic Republic of Congo

2013 ◽  
Vol 16 (8) ◽  
pp. 1362-1370 ◽  
Author(s):  
Laurence Habimana ◽  
Kabange E Twite ◽  
Pierre Wallemacq ◽  
Philippe De Nayer ◽  
Chantal Daumerie ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Urban Area ◽  
Urban Areas ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Iodine Intake ◽  
Postpartum Women ◽  
Urinary Iodine Concentration ◽  
Third Trimester ◽  
Republic Of Congo

AbstractObjectiveAdequate iodine and Fe intakes are imperative during pregnancy to prevent fetal defects, but such data are not available in the Democratic Republic of Congo. We aimed to assess iodine and Fe status in pregnant women from Lubumbashi.DesignCross-sectional study. We measured urinary iodine concentration (UIC) in random urine samples using a modified Sandell–Kolthoff digestion method; the WHO reference medians were used to classify iodine intake as deficient, adequate, more than adequate or excessive. Serum ferritin concentrations were measured by immunoenzymatic assay and considered insufficient when <12 ng/ml.SettingMaternity units from rural, semi-urban and urban areas of Lubumbashi, Democratic Republic of Congo.SubjectsTwo hundred and twenty-five randomly selected pregnant women attending prenatal consultation, seventy-five postpartum women and seventy-five non-pregnant women as controls.ResultsOverall median UIC in pregnant women was 138 (interquartile range: 105–172) μg/l, indicating iodine deficiency, whereas postpartum and non-pregnant women had adequate iodine intake: median UIC = 144 μg/l and 204 μg/l, respectively. Median UIC values were lower in late pregnancy than in early pregnancy: in the first, second and third trimester respectively 255 μg/l, 70 μg/l and 88 μg/l in the rural area; 306 μg/l, 166 μg/l and 68 μg/l in the semi-urban area; and 203 μg/l, 174 μg/l and 99 μg/l in the urban area. Fe was insufficient in 39 % of pregnant women compared with 21 % of non-pregnant and postpartum women. In the third trimester, deficiencies in both iodine and Fe were high: 40 %, 12 % and 18 % in the rural, semi-urban and urban areas, respectively.ConclusionsOur data suggest that pregnant women are at risk of iodine and Fe deficiencies in Lubumbashi. Country policies fighting against iodine and Fe deficiencies during pregnancy should be reinforced.

scholarly journals Amniotic fluid iodine concentrations do not vary in pregnant women with varying iodine intake

2008 ◽  
Vol 99 (6) ◽  
pp. 1178-1181 ◽  
Author(s):  
Eduardo García-Fuentes ◽  
Manuel Gallo ◽  
Laureano García ◽  
Stephanie Prieto ◽  
Javier Alcaide-Torres ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Pregnant Women ◽  
Urinary Iodine ◽  
Public Health Problem ◽  
Iodine Concentration ◽  
Iodine Intake ◽  
Iodized Salt ◽  
Cross Sectional ◽  
International Agencies ◽  
Multivitamin Supplement

Iodine deficiency is an important clinical and public health problem. Its prevention begins with an adequate intake of iodine during pregnancy. International agencies recommend at least 200 μg iodine per d for pregnant women. We assessed whether iodine concentrations in the amniotic fluid of healthy pregnant women are independent of iodine intake. This cross-sectional, non-interventional study included 365 consecutive women who underwent amniocentesis to determine the fetal karyotype. The amniocentesis was performed with abdominal antisepsis using chlorhexidine. The iodine concentration was measured in urine and amniotic fluid. The study variables were the intake of iodized salt and multivitamin supplements or the prescription of a KI supplement. The mean level of urinary iodine was 139·0 (sd94·5) μg/l and of amniotic fluid 15·81 (sd7·09) μg/l. The women who consumed iodized salt and those who took a KI supplement had significantly higher levels of urinary iodine than those who did not (P = 0·01 andP = 0·004, respectively). The urinary iodine levels were not significantly different in the women who took a multivitamin supplement compared with those who did not take this supplement, independently of iodine concentration or multivitamin supplement. The concentrations of iodine in the amniotic fluid were similar, independent of the dietary iodine intake. Urine and amniotic fluid iodine concentrations were weakly correlated, although the amniotic fluid values were no higher in those women taking a KI supplement. KI prescription at recommended doses increases the iodine levels in the mother without influencing the iodine levels in the amniotic fluid.

scholarly journals Reference Intervals of Thyroid Hormones and Correlation of BMI with Thyroid Function in Healthy Zhuang Ethnic Pregnant Women

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yonghong Sheng ◽  
Dongping Huang ◽  
Shun Liu ◽  
Xuefeng Guo ◽  
Jiehua Chen ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Pregnant Women ◽  
Thyroid Function ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Specific Reference ◽  
American Thyroid Association ◽  
Reference Ranges ◽  
Free Triiodothyronine ◽  
Cross Sectional

Ethnic differences in the level of thyroid hormones exist among individuals. The American Thyroid Association (ATA) recommends that an institution or region should establish a specific thyroid hormone reference value for each stage of pregnancy. To date, a limited number of studies have reported the level of thyroid hormones in Chinese minorities, and the exact relationship between BMI and thyroid function in pregnant women is ill. This study was performed to establish trimester-specific reference ranges of thyroid hormones in Zhuang ethnic pregnant women and explore the role of body mass index (BMI) on thyroid function. A total of 3324 Zhuang ethnic health pregnant women were recruited in this Zhuang population-based retrospective cross-sectional study. The values of thyroid stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were determined by automatic chemiluminescence immunoassay analyzer. Multivariate linear regression and binary logistic regression were constructed to evaluate the influence of BMI on the thyroid function. The established reference intervals for the serum thyroid hormones in three trimesters were as follows: TSH, 0.02–3.28, 0.03–3.22, and 0.08-3.71 mIU/L; FT4, 10.57–19.76, 10.05–19.23, and 8.96–17.75 pmol/L; FT3, 3.51–5.64, 3.42–5.42, and 2.93–5.03 pmol/L. These values were markedly lower than those provided by the manufacturers for nonpregnant adults which can potentially result in 6.10% to 19.73% misclassification in Zhuang pregnant women. Moreover, BMI was positively correlated with isolated hypothyroxinemia (OR=1.081, 95% CI=1.007–1.161), while the correlation between the BMI and subclinical hypothyroidism was not statistically significant (OR=0.991, 95% CI=0.917–1.072). This is the first study focusing on the reference ranges of thyroid hormones in Guangxi Zhuang ethnic pregnant women, which will improve the care of them in the diagnosis and treatment. We also found that high BMI was positively associated with the risk of isolated hypothyroxinemia.

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