Trimester-Specific Thyroid Function in Pregnant Women with Different Iodine Statuses

2020 ◽  
Vol 76 (3) ◽  
pp. 165-174
Author(s):  
Wenxing Guo ◽  
Wei Wang ◽  
Ya Jin ◽  
Wen Chen ◽  
Lu Chen ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Urinary Iodine ◽  
Thyroid Volume ◽  
First Trimester ◽  
Urinary Iodine Concentration ◽  
Free Triiodothyronine ◽  
Cross Sectional ◽  
Iodine Status ◽  
Spot Urine

Objectives: To explore trimester-specific thyroid function changes under different iodine statuses throughout pregnancy. Methods: A cross-sectional study was conducted to assess the pregnancy iodine status, and 2,378 healthy pregnant women covering all 3 trimesters were recruited. Urinary iodine concentration (UIC) was measured by collecting spot urine samples. Blood samples were collected to evaluate thyroid function. Thyroid B-ultrasonography was conducted to measure the thyroid volume (Tvol). Results: The median UIC was 168 μg/L (111–263 μg/L). The UIC, free triiodothyronine (FT3), and free thyroxine (FT4) were significantly decreased as the pregnancy progressed (p < 0.001, p for trend <0.001), while Tvol increased (p < 0.001, p for trend <0.001). Thyrotropin (TSH) was significantly different between the 3 trimesters and showed an upward trend (p < 0.001), but the p for trend was not significant (p for trend = 0.88). After stratification by UIC, there were no significant differences in serum TSH, FT4, or FT3 level between UIC groups. Tvol was significantly higher in the UIC ≥500 μg/L group in the first trimester (β: 2.41, 95% CI: 1.09–3.72, p <0.001), as well as in the 250 ≤ UIC < 500 μg/L group (β: 1.65, 95% CI: 0.61–2.70, p < 0.001) and UIC ≥500 μg/L group (β: 3.35, 95% CI: 1.96–4.74, p < 0.001) in the third trimester. Conclusions: No difference was observed in TSH, FT3, or FT4 among the different iodine status groups throughout pregnancy. Tvol increased as the pregnancy progressed, and it was especially higher in the UIC ≥500 μg/L group in the first and third trimesters.

scholarly journals High prevalence of iodine deficiency in pregnant women living in adequate iodine area

2018 ◽  
Vol 7 (5) ◽  
pp. 762-767 ◽  
Author(s):  
Verônica Carneiro Borges Mioto ◽  
Ana Carolina de Castro Nassif Gomes Monteiro ◽  
Rosalinda Yossie Asato de Camargo ◽  
Andréia Rodrigues Borel ◽  
Regina Maria Catarino ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Iodine Deficiency ◽  
Urinary Iodine ◽  
Thyroid Volume ◽  
Adverse Outcomes ◽  
Urinary Iodine Concentration ◽  
Serum Thyroglobulin ◽  
Cross Sectional ◽  
Iodine Status

Objectives Iodine deficiency during pregnancy is associated with obstetric and neonatal adverse outcomes. Serum thyroglobulin (sTg) and thyroid volume (TV) are optional tools to urinary iodine concentration (UIC) for defining iodine status. This cross-sectional study aims to evaluate the iodine status of pregnant women living in iodine-adequate area by spot UIC and correlation with sTg, TV and thyroid function. Methods Two hundred and seventy-three pregnant women were evaluated at three trimesters. All had no previous thyroid disease, no iodine supplementation and negative thyroperoxidase and thyroglobulin antibodies. Thyroid function and sTg were measured using electrochemiluminescence immunoassays. TV was determined by ultrasonography; UIC was determined using a modified Sandell–Kolthoff method. Results Median UIC was 146 µg/L, being 52% iodine deficient and only 4% excessive. TSH values were 1.50 ± 0.92, 1.50 ± 0.92 and 1.91 ± 0.96 mIU/L, respectively, in each trimester (P = 0.001). sTg did not change significantly during trimesters with median 11.2 ng/mL and only 3.3% had above 40 ng/mL. Mean TV was 9.3 ± 3.4 mL, which positively correlated with body mass index, but not with sTg. Only 4.5% presented with goitre. When pregnant women were categorized as iodine deficient (UIC < 150 µg/L), adequate (≥150 and <250 µg/L) and excessive (≥250 µg/L), sTg, thyroid hormones and TV at each trimester showed no statistical differences. Conclusions Iodine deficiency was detected frequently in pregnant women living in iodine-adequate area. sTg concentration and TV did not correlate to UIC. Our observation also demonstrated that the Brazilian salt-iodization programme prevents deficiency, but does not maintain iodine status within adequate and recommended ranges for pregnant women.

scholarly journals Urinary Iodine Concentration as an Indicator of Iodine Status and its Correlation with the Thyroid Hormones and Hemoglobin Levels in First Trimester Pregnant Women - An Exploratory Study

2021 ◽  
Vol 9 (3) ◽  
pp. 791-799
Author(s):  
Syeda Farha S ◽  
Asna Urooj
Keyword(s):  
Pregnant Women ◽  
Iron Status ◽  
Urinary Iodine ◽  
Iodine Concentration ◽  
First Trimester ◽  
Iodine Intake ◽  
Urinary Iodine Concentration ◽  
Cross Sectional ◽  
Iodine Status ◽  
The Impact

During pregnancy, the daily requirement of iodine increases making those most at-risk population for iodine deficiency disorders. The available confined data shows that pregnant women are iodine deficient even in iodine sufficient regions with this background the objectives of the current study were to assess the urinary iodine concentration (UIC) and evaluate the relationship between the levels of hemoglobin, UIC, and thyroid status in first-trimester pregnant women. A cross-sectional hospital-based study with a total sample size of n=110 pregnant women at the13th week of gestation in the Mysuru district was selected. The UIC, anthropometric measurements, iodine intake, and selected biochemical parameters (TSH, FT3, FT4, and Hb) were assessed. The data was analysed using SPSS (v 16.0). Spearman’s rank correlation test was used to analyse correlations. The Mann- Whitney U test was used to compare differences between groups. ANOVA was used to study the comparison of pregnancy complications with UIC and hemoglobin. The median UIC (mUIC) was 194.2 µg/L and Hb was 10.5 g/dL. Even though the mUIC was normal, around 38.2% had insufficient UIC. Significant inverse relationship between UIC and TSH (r = -0.487, p<0.001), Hb and TSH (r = -0.355, p < 0.001), and between TSH and iodine intake (r=-0.476, p<0.001) were observed. It was interesting to observe that those with insufficient UIC were found to have mild anaemia and low FT4 levels and those with excess UIC had lower TSH levels. The pregnant women in the present study were found to have the normal median urinary iodine concentration and were mildly anaemic. Increased attention among pregnant women should be focused on iodine status along with iron status and thyroid functions. Larger comparative studies need to be performed to study the impact of altered iodine status on neonatal outcomes.

scholarly journals Infant neurocognitive development is independent of the use of iodised salt or iodine supplements given during pregnancy

2013 ◽  
Vol 110 (5) ◽  
pp. 831-839 ◽  
Author(s):  
Piedad Santiago ◽  
Inés Velasco ◽  
Jose Antonio Muela ◽  
Baltasar Sánchez ◽  
Julia Martínez ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Urinary Iodine ◽  
Thyroid Volume ◽  
First Trimester ◽  
Thyroid Stimulating Hormone ◽  
Neurological Development ◽  
Free Triiodothyronine ◽  
Iodised Salt ◽  
Maternal Thyroid

The benefits of iodine supplements during pregnancy remain controversial in areas with a mild-to-moderate iodine deficiency. The aim of the present study was to determine the effect of improving iodine intakes, with iodised salt (IS) or iodine supplements, in pregnant Spanish women. A total of 131 pregnant women in their first trimester were randomly assigned to three groups: (1) IS in cooking and at the table, (2) 200 μg potassium iodide (KI)/d or (3) 300 μg KI/d. No differences were found in thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) or thyroid volume (TV) between the three groups. Regardless of the group in which women were included, those who had been taking IS for at least 1 year before becoming pregnant had a significantly lower TV in the third trimester (P= 0·01) and a significantly higher urinary iodine in the first (173·7 (sd81·8)v. 113·8 (sd79·6) μg/l,P= 0·001) and third trimesters (206·3 (sd91·2)v. 160·4 (sd87·7) μg/l,P= 0·03). Also, no differences were seen in TSH, FT4 or FT3. Children's neurological development was not significantly associated with the consumption of IS for at least 1 year before becoming pregnant and no differences were found according to the treatment group. In conclusion, in pregnant women with insufficient iodine intake, the intake of IS before becoming pregnant was associated with a better maternal thyroid function. The form of iodide intake was not associated with maternal thyroid function or children's neurological development.

scholarly journals Nutritional Iodine Status in Pregnant Women from Health Area IV in Asturias (Spain): Iodised Salt Is Enough

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1816
Author(s):  
Silvia González-Martínez ◽  
María Riestra-Fernández ◽  
Eduardo Martínez-Morillo ◽  
Noelia Avello-Llano ◽  
Elías Delgado-Álvarez ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Iodine Deficiency ◽  
Urinary Iodine ◽  
Multivariate Logistic Regression Analysis ◽  
First Trimester ◽  
Urinary Iodine Concentration ◽  
Iodine Status ◽  
Iodised Salt ◽  
Health Area

Background: Iodine deficiency during pregnancy may have adverse effects on the neurodevelopment of the foetus. Recent studies of pregnant women in Asturias (Spain) indicate that nutritional iodine levels are sufficient. The objective of this study was to confirm the appropriate nutritional iodine status and to analyse the influence of the ingestion of iodine on maternal urinary iodine concentration (UIC) and thyroid function. Methods: An observational study was carried out between May and June 2017 on women in the first trimester of pregnancy from Health Area IV in Asturias. The women completed a questionnaire related to their consumption of iodine and samples were taken to analyse UIC and thyroid function. Results: Three hundred and eighteen pregnant women were involved. Of these, 51.10% used iodised salt, 48.90% consumed ≥ 2 servings of dairy products daily and 87.08% took iodine supplements. The median UIC was 171.5 μg/L (116–265 μg/L) and 60.41% of women had UIC ≥ 150 μg/L. Multivariate logistic regression analysis demonstrated that iodised salt had a protective effect on UIC < 150 μg/L (odds ratio (OR) 0.404 (0.237–0.683), p = 0.001), but not iodine supplements (OR 0.512 (0.240–1.085), p = 0.080). The average level of thyroid stimulating hormone (TSH) was 2.26 ± 0.94 mIU/L; 68.40% of pregnant women taking iodine supplements had TSH < 2.5 mIU/L compared to 30.00% of those who were not taking supplements (p = 0.031). Conclusions: The pregnant women in our health area are maintaining appropriate nutritional iodine levels. The consumption of iodised salt protects against iodine deficiency; thus, iodine supplements should be taken on an individualised basis.

scholarly journals Dried Blood Spot Thyroglobulin as a Biomarker of Iodine Status in Pregnant Women

2016 ◽  
Vol 102 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Sara Stinca ◽  
Maria Andersson ◽  
Sandra Weibel ◽  
Isabelle Herter-Aeberli ◽  
Ralph Fingerhut ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Reference Range ◽  
Urinary Iodine ◽  
Iodine Intake ◽  
Dried Blood Spot ◽  
Urinary Iodine Concentration ◽  
Iodine Nutrition ◽  
Cross Sectional ◽  
Iodine Status ◽  
Blood Spot

Abstract Context: Thyroglobulin (Tg) could be a sensitive biomarker of iodine nutrition in pregnant women (PW). A dried blood spot (DBS) assay would simplify collection and transport in field studies. Objectives: Our aims were to (1) establish and test a reference range for DBS-Tg in PW; (2) determine whether co-measurement of Tg antibodies (Abs) is necessary to define population iodine status. Design, Setting, and Participants: Standardized cross-sectional studies of 3870 PW from 11 countries. For the DBS-Tg reference range, we included TgAb-negative PW (n = 599) from 3 countries with sufficient iodine intake. Main Outcome Measures: We measured the urinary iodine concentration and DBS thyroid-stimulating hormone, total thyroxin, Tg, and TgAb. Results: In the reference population, the median DBS-Tg was 9.2 μg/L (95% confidence interval, 8.7 to 9.8 μg/L) and was not significantly different among trimesters. The reference range was 0.3 to 43.5 μg/L. Over a range of iodine intake, the Tg concentrations were U-shaped. Within countries, the median DBS-Tg and the presence of elevated DBS-Tg did not differ significantly between all PW and PW who were TgAb-negative. Conclusions: A median DBS-Tg of ∼10 μg/L with &lt;3% of values ≥44 μg/L indicated population iodine sufficiency. Concurrent measurement of TgAb did not appear necessary to assess the population iodine status.

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.

Saliva Iodine Concentration in Children and Its Association with Iodine Status and Thyroid Function

2020 ◽  
Vol 105 (9) ◽  
pp. e3451-e3459 ◽  
Author(s):  
Wenxing Guo ◽  
Ziyun Pan ◽  
Ying Zhang ◽  
Ya Jin ◽  
Shuyao Dong ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Primary Schools ◽  
Urinary Iodine ◽  
Reference Value ◽  
Iodine Concentration ◽  
Cross Sectional Study ◽  
Urinary Iodine Excretion ◽  
Urinary Iodine Concentration ◽  
Cross Sectional ◽  
Iodine Status

Abstract Context The effectiveness of saliva iodine concentration (SIC) in evaluating iodine status in children is not clear. Objective We aimed to explore associations between SIC and assessed indicators of iodine status and thyroid function. Design Cross-sectional study. Setting Primary schools in Shandong, China. Participants Local children aged 8 to 13 years with no known thyroid disease were recruited to this study. Main outcome measures Blood, saliva, and urine samples were collected to evaluate thyroid function and iodine status. Results SIC positively correlated with spot urinary iodine concentration (r = 0.29, P &lt; 0.0001), 24-hour urinary iodine concentration (r = 0.35, P &lt; 0.0001), and 24-hour urinary iodine excretion (r = 0.40, P &lt; 0.0001). The prevalence of thyroid nodules (TN) and goiter showed an upward trend with SIC quantiles (P for trend &lt; 0.05). Children with SIC &lt;105 μg/L had a higher risk of insufficient iodine status (OR = 4.18; 95% CI, 2.67-6.56) compared with those with higher SIC. Those having SIC &gt;273 μg/L were associated with greater risks of TN (OR = 2.70; 95% CI, 1.38-5.26) and excessive iodine status (OR = 18.56; 95% CI, 5.66-60.91) than those with lower SIC values. Conclusions There is a good correlation between SIC and urinary iodine concentrations. It is of significant reference value for the diagnosis of iodine deficiency with SIC of less than 105 μg/L and for the diagnosis of iodine excess and TN with SIC of more than 273 μg/L. Given the sanitary nature and convenience of saliva iodine collection, SIC is highly recommended as a good biomarker of recent iodine status in school-aged children.

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 Iodine Status and Thyroid Function in a Group of Seaweed Consumers in Norway

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3483
Author(s):  
Inger Aakre ◽  
Lidunn Tveito Evensen ◽  
Marian Kjellevold ◽  
Lisbeth Dahl ◽  
Sigrun Henjum ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Urinary Iodine ◽  
Iodine Content ◽  
Iodine Concentration ◽  
Iodine Intake ◽  
Thyroid Stimulating Hormone ◽  
Urinary Iodine Concentration ◽  
Free Triiodothyronine ◽  
Iodine Status ◽  
Excessive Iodine

Seaweeds, or macroalgae, may be a good dietary iodine source but also a source of excessive iodine intake. The main aim in this study was to describe the iodine status and thyroid function in a group of macroalgae consumers. Two urine samples were collected from each participant (n = 44) to measure urinary iodine concentration (UIC) after habitual consumption of seaweed. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and peroxidase autoantibody (TPOAb), were measured in a subgroup (n = 19). A food frequency questionnaire and an iodine-specific 24 h recall were used to assess iodine intake and macroalgae consumption. The median (p25–p75) UIC was 1200 (370–2850) μg/L. Median (p25–p75) estimated dietary iodine intake, excluding macroalgae, was 110 (78–680) μg/day, indicating that seaweed was the major contributor to the iodine intake. TSH levels were within the reference values, but higher than in other comparable population groups. One third of the participants used seaweeds daily, and sugar kelp, winged kelp, dulse and laver were the most common species. Labelling of iodine content was lacking for a large share of the products consumed. This study found excessive iodine status in macroalgae consumers after intake of dietary seaweeds. Including macroalgae in the diet may give excessive iodine exposure, and consumers should be made aware of the risk associated with inclusion of macroalgae in their diet.

scholarly journals IODINE STATUS OF PREGNANT WOMEN RESIDING IN URBAN SLUMS IN DELHI

2018 ◽  
Vol 11 (7) ◽  
pp. 506
Author(s):  
Spriha Rao ◽  
Gurudayal Singh Toteja ◽  
Neena Bhatia ◽  
Supriya Dwivedi ◽  
Zaozianlungliu Gonmei ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Urinary Iodine ◽  
Urban Slums ◽  
Iodized Salt ◽  
Nutrition Status ◽  
Urinary Iodine Concentration ◽  
Iodine Nutrition ◽  
Cross Sectional ◽  
Iodine Status ◽  
Salt Iodine

Objectives: The present study was carried out to determine the iodine nutrition status among pregnant women in slums of West Delhi.Methods: A community-based cross-sectional study was carried out among the third-trimester pregnant women residing in urban slums of West Delhi. Urinary iodine concentration was estimated using ammonium persulfate method, and salt iodine was estimated using iodometric titration.Results: Of the total 180 pregnant women, 70.6% were consuming adequately iodized salt (iodine levels ≥15 ppm). Median urinary iodine level for the pregnant women was 147.5 μg/L indicating iodine deficiency among this group. A total of 51.1% of women had urinary iodine levels <150 μg/L.Conclusion: Pregnant women belonging to slum community from Delhi have a suboptimal iodine status. Further, the proportion of women consuming iodized salt is less than the national average indicating the need to educate these women about the importance of iodine during pregnancy.

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