Impact of iodine supplementation during preconception, pregnancy and lactation on maternal thyroid homeostasis and offspring psychomotor development: protocol of the IodineMinho prospective study

Abstract Background Iodine deficiency is the most common cause of preventable brain harm and cognitive impairment in children. Portuguese women of childbearing age, pregnant women and their progeny were shown to have inadequate iodine intake. Consequently, the Portuguese Health Authorities have recommended a daily supplementation with 150–200 µg iodine in preconception, pregnancy, and lactation. The IodineMinho study intends to evaluate whether (i) this recommendation impacted on the prevalence of iodine deficiency in pregnant women from the Minho region of Portugal, (ii) the time of initiation of iodine supplementation (if any) influences the serum levels of thyroid hormones at several intervals during pregnancy and (iii) there are serum thyroid-hormone parameters in the 1st trimester of pregnancy that predict psychomotor development of the child at 18 months of age. Methods Most Portuguese women are followed throughout pregnancy in community Family Health Units, where family physicians may choose to follow the National recommendation or other, concerning iodine sufficiency. This study will recruit women (N = 304) who intend to become pregnant or are already pregnant from 10 representative Units. Physician’s approach and prescriptions, sociodemographic, nutrition and clinical information will be obtained at baseline and throughout pregnancy. To evaluate endocrine function, blood and urine samples will be collected at recruitment, once in each trimester of pregnancy, at delivery and 3 months after delivery. Breastmilk samples will be collected for iodine and energy content analysis. Children will be evaluated for psychomotor development at 18 months. Maternal thyroid volume will be evaluated by ultrasound scan at baseline, in the 3rd trimester and at 3 months after delivery. Discussion Iodine deficiency early during development precludes children from achieving full intellectual capabilities. This protocol describes a study that is innovative and unique in its detailed and comprehensive evaluation of maternal and child endocrine and psychomotor parameters. By evaluating the effectiveness of the iodine supplementation recommendation, it will contribute to the public health systems’ efforts to provide excellence in maternal and infant care. Trial registration ClinicalTrials.gov, NCT04288531. Registered 28 February 2020-Retrospectively registered.

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Iodine supplementation: compliance and association with adverse obstetric and neonatal outcomes

European Thyroid Journal ◽

10.1530/etj-21-0035 ◽

2022 ◽

Vol 11 (1) ◽

Author(s):

Maria Lopes-Pereira ◽

Anna Quialheiro ◽

Patrício Costa ◽

Susana Roque ◽

Nadine Correia Santos ◽

...

Keyword(s):

Pregnant Women ◽

Fetal Loss ◽

Family Health ◽

Neonatal Outcomes ◽

Vulnerable Groups ◽

Psychomotor Development ◽

Obstetric Outcomes ◽

Childbearing Age ◽

Iodine Supplementation ◽

The Impact

Objectives Over 1.9 billion people worldwide are living in areas estimated to be iodine insufficient. Strategies for iodine supplementation include campaigns targeting vulnerable groups, such as women in pre-conception, pregnancy and lactation. Portuguese women of childbearing age and pregnant women were shown to be mildly-to-moderately iodine deficient. As a response, in 2013, the National Health Authority (NHA) issued a recommendation that all women considering pregnancy, pregnant or breastfeeding, take a daily supplement of 150–200 μg iodine. This study explored how the iodine supplementation recommendation has been fulfilled among pregnant and lactating women in Portugal, and whether the reported iodine supplements intake impacted on adverse obstetric and neonatal outcomes. Design and methods Observational retrospective study on pregnant women who delivered or had a fetal loss in the Braga Hospital and had their pregnancies followed in Family Health Units. Results The use of iodine supplements increased from 25% before the recommendation to 81% after the recommendation. This was mostly due to an increase in the use of supplements containing iodine only. Iodine supplementation was protective for the number of adverse obstetric outcomes (odds ratio (OR) = 0.791, P = 0.018) and for neonatal morbidities (OR = 0.528, P = 0.024) after controlling for relevant confounding variables. Conclusion The recommendation seems to have succeeded in implementing iodine supplementation during pregnancy. National prospective studies are now needed to evaluate the impact of iodine supplementation on maternal thyroid homeostasis and offspring psychomotor development and on whether the time of the beginning of iodine supplementation (how early during preconception or pregnancy) is relevant to consider.

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Earliest prevention of endemic goiter by iodine supplementation during pregnancy

Acta Endocrinologica ◽

10.1530/eje.0.1340443 ◽

1996 ◽

Vol 134 (4) ◽

pp. 443-448 ◽

Cited By ~ 90

Author(s):

Klaus Peter Liesenkötter ◽

Wolfgang Göpel ◽

Ulrich Bogner ◽

Barbara Stach ◽

Annette Grüters

Keyword(s):

Thyroid Function ◽

Iodine Deficiency ◽

Endemic Goiter ◽

Urinary Iodine ◽

Thyroid Volume ◽

Urinary Iodine Excretion ◽

Thyroid Peroxidase ◽

Iodine Supplementation ◽

Iodine Excretion ◽

Maternal Thyroid

Liesenkötter KP, Göpel W, Bogner U, Stach B, Grüters A. Earliest prevention of endemic goiter by iodine supplementation during pregnancy. Eur J Endocrinol 1996;134:443–8. ISSN 0804–4643 During pregnancy complex changes of maternal thyroid function occur and they are influenced by the maternal iodine supply. It has been demonstrated that with decreasing iodine supply maternal goiter and hypothyroxinemia as well as fetal and neonatal hypothyroidism become more prevalent. Therefore iodine supplementation during pregnancy is now strongly recommended also in areas of moderate iodine deficiency. To monitor the success of iodine supplementation and its theoretical risk of increasing the frequency of thyroid autoantibodies, we have investigated the thyroid volume, thyroid function, urinary iodine excretion and antibodies to thyroid peroxidase at 10–12 weeks of gestation and postpartum in 38 mothers receiving 300 μg potassium iodide/day and in 70 mothers without iodine supplementation. In all of their newborns thyroid volume was determined by ultrasound. The thyrotropin (TSH) levels and antibodies to thyroid peroxidase (TPO-ab) in the neonates were measured in dried blood spots on filter paper from their newborn screening. Urinary iodine excretion was increased significantly after iodine supplementation in mothers (p < 0.001) and their newborns (<0.05). No hypo- or hyperthyroidism was observed in the mothers or newborns. Interestingly, no difference of maternal thyroid volumes was observed between the two groups after pregnancy, but the volumes of the thyroid glands in newborns of mothers who received iodine were significantly (p < 0.004) lower (0.7 ± 0.4 ml) than in the control group (1.5 ± 1.1 ml). There was no change in the frequency of TPO-ab in either group after pregnancy. In four mothers transplacental passage of these antibodies was documented by positive measurement in the blood sample of the newborn. This study documents that iodine supplementation during pregnancy in an area of moderate iodine deficiency results in a lower size of neonatal thyroid volume and that this supplementation was not accompanied by an increase in the frequency of TPO-ab. Klaus Peter Liesenkötter, Kinderklinik Kaiserin Auguste Victoria Haus (KAVH), Virchow-Klinikum der Medizinische Fakultät der Humboldt-Universität zu Berlin, Heubnerweg 6, 14059 Berlin, Germany

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Study on Association between Height, Weight, Iodine Supplementation and Thyroid Volume

British Journal Of Nutrition ◽

10.1017/s0007114521002622 ◽

2021 ◽

pp. 1-25

Author(s):

Lanchun Liu ◽

Lixiang Liu ◽

Ming Li ◽

Yang Du ◽

Peng Liu ◽

...

Keyword(s):

Iodine Deficiency ◽

Linear Models ◽

Thyroid Volume ◽

Salt Iodization ◽

Iodine Supplementation ◽

Random Pairing ◽

Level Data ◽

The Mean ◽

Salt Iodine ◽

The Difference

Abstract The policy of Universal Salt Iodization (USI) could reduce population’s thyroid volume (TVOL) in iodine deficiency areas. Conversely, the improved growth and developmental status of children might increase the TVOL accordingly. Whether the decreased TVOL by USI conceals the increase effect of height and weight on TVOL is unclear. The aim of this study was to analyse the association between height, weight, iodine supplementation and TVOL. Five national Iodine Deficiency Disorder surveys were matched into four pairs according to the purpose of analysis. County-level data of both detected by paired surveys were incorporated, 1: 1 random pairing method was used to match counties or individuals. The difference of TVOL between different height, weight, different iodine supplementation measures groups and the association between TVOL and them were studied. The mean height and weight of children aged 8-10 years increased from 129.9cm and 26.9kg in 2002 to 136.2cm and 32.1kg in 2019; while the median TVOL decreased from 3.10ml to 2.61ml. Iodine supplementation measures can affect TVOL; after exclude iodine effects, the median TVOL was increased with the height and weight. On the other side, after excluding the influence of height and weight, the median TVOL remained decreased. Only age, weight and salt iodine were significant associated with TVOL in multiple linear models. Development of height and weight in children is the evidence of improved nutrition. The decreased TVOL caused by iodized salt measures conceals the increase effect of height and weight on TVOL. Age, weight, and salt iodine affect TVOL significantly.

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Study of Urinary Iodine Level Assessment and its Relation to Thyroid Function during Pregnancy

QJM ◽

10.1093/qjmed/hcab100.103 ◽

2021 ◽

Vol 114 (Supplement_1) ◽

Author(s):

Magda Shoukry Mohamed ◽

Merhan Samy Nasr ◽

Salah Hussien El-Halawany ◽

Ahmed Mohamed Abbas ◽

Salma Said Hassan Tayeh

Keyword(s):

Iodine Deficiency ◽

Urinary Iodine ◽

Thyroid Volume ◽

Significant Negative Correlation ◽

Iodine Deficiency Disorders ◽

Iodine Excess ◽

Salt Iodization ◽

Excess Iodine ◽

Iodine Supplementation ◽

Iodine Level

Abstract Background The global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to poor monitoring, is currently a more frequent occurrence than iodine deficiency. Iodine excess is a precipitating environmental factor in the development of autoimmune thyroid disease. Aim of the study to evaluate the urinary iodine level as a marker of iodine status in pregnant women in 3rd trimester and assess its relation to thyroid functions. Patients and Methods This Cross Sectional Study was conducted on 100 subjects with their ages ranging from 18-35 years old, pregnant females, at the third trimester, selected from Obstetric Out- patient Clinic of Ain shams University Hospitals. Samples were collected from participants in cairo, during the Spring and Summer from March to August. Results in our study, there was a significant negative correlation between Urinary Iodine level and TSH as Iodine difficient group has the Highest TSH, and the Highest Thyroid Volume, as there was a significant negative correlation between Urinary Iodine level and Thyroid Volume. Conclusion TSH level and Thyroid Volume were global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to significantly higher in Iodine difficient group than Excess iodine group, And FT4 level was lower in Iodine difficient group than excess iodine group.

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Iodine Deficiency and Schooling Attainment in Tanzania

American Economic Journal Applied Economics ◽

10.1257/app.1.4.140 ◽

2009 ◽

Vol 1 (4) ◽

pp. 140-169 ◽

Cited By ~ 48

Author(s):

Erica Field ◽

Omar Robles ◽

Maximo Torero

Keyword(s):

Economic Growth ◽

Human Capital ◽

Iodine Deficiency ◽

In Utero ◽

Iodine Deficiency Disorders ◽

Laboratory Evidence ◽

Iodine Supplementation ◽

Maternal Thyroid ◽

The Impact

Cognitive damage from iodine deficiency disorders (IDD) has important implications for economic growth through its effect on human capital. To gauge the magnitude of this influence, we evaluate the impact on schooling of reductions in IDD from intensive iodine supplementation in Tanzania. Our findings suggest a large effect of in utero iodine on cognition and human capital: treated children attain an estimated 0.35–0.56 years of additional schooling relative to siblings and older and younger peers. Furthermore, the effect appears to be substantially larger for girls, consistent with laboratory evidence indicating greater cognitive sensitivity of female fetuses to maternal thyroid deprivation. (JEL I12, I21, J16, O15)

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Iodine deficiency in pregnant women living in the South East of the UK: the influence of diet and nutritional supplements on iodine status

British Journal Of Nutrition ◽

10.1017/s0007114513004030 ◽

2014 ◽

Vol 111 (9) ◽

pp. 1622-1631 ◽

Cited By ~ 60

Author(s):

Sarah C. Bath ◽

Alan Walter ◽

Andrew Taylor ◽

John Wright ◽

Margaret P. Rayman

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

World Health ◽

The South ◽

Childbearing Age ◽

Iodine Status ◽

Supplement Use ◽

Iodine Excretion ◽

The Uk

Iodine is a key component of the thyroid hormones which are crucial for brain development. Adequate intake of iodine in pregnancy is important as in utero deficiency may have lifelong consequences for the offspring. Data on the iodine status of UK pregnant women are sparse, and there are no such data for pregnant women in the South East of the UK. A total of 100 pregnant women were recruited to a cross-sectional study carried out at the Royal Surrey County Hospital, Guildford, at their first-trimester visit for an ultrasound scan. The participants provided a spot-urine sample (for the measurement of urinary iodine concentration (UIC) and creatinine concentration) and 24 h iodine excretion was estimated from the urinary iodine:creatinine ratio. Women completed a general questionnaire and a FFQ. The median UIC (85·3 μg/l) indicated that the group was iodine deficient by World Health Organisation criteria. The median values of the iodine:creatinine ratio (122·9 μg/g) and of the estimated 24 h iodine excretion (151·2 μg/d) were also suggestive of iodine deficiency. UIC was significantly higher in women taking an iodine-containing prenatal supplement (n 42) than in those not taking such a supplement (P< 0·001). In the adjusted analyses, milk intake, maternal age and iodine-containing prenatal supplement use were positively associated with the estimated 24 h urinary iodine excretion. Our finding of iodine deficiency in these women gives cause for concern. We suggest that women of childbearing age and pregnant women should be given advice on how to improve their iodine status through dietary means. A national survey of iodine status in UK pregnant women is required.

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Iodine adequacy in reproductive age women living in the Western region of Saudi Arabia

10.21203/rs.2.14261/v1 ◽

2019 ◽

Author(s):

Firas Azzeh ◽

Bassem Amr Refaat

Keyword(s):

Saudi Arabia ◽

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

The Other ◽

Reproductive Age ◽

Childbearing Age ◽

Who Criteria ◽

Saudi Women ◽

Other Hand

Abstract Background Despite the significance of iodine deficiency in women of reproductive age due its associated serious maternal and foetal complications, surveys related to this vulnerable population in the Kingdom of Saudi Arabia (KSA) are lacking. This study, therefore, aimed to measure the frequency alongside the potential socioeconomic factors contributing towards iodine inadequacy in Saudi women of childbearing age from the Western province of KSA.Methods Urinary iodine concentrations IUIC) were measured in random spot samples collected from 1222 pregnant women and 400 age-matched non-pregnant/non-lactating women. The socioeconomic characteristics were obtained through a structured questionnaire. The classification of iodine sufficiency was based on the WHO criteria for UIC in pregnant (150–249 μg/L) and non-pregnant women (100–199 μg/L).Results The UIC median in the non-pregnant women (101.64 μg/L; IQR: 73.72) was at the lowest WHO recommended cut-off. The pregnant women, on the other hand, had a median UIC (112.99 μg/L; IQR: 104.56) markedly below the minimal WHO limit for pregnancy. Coherently, the median IUC was below adequacy across the trimesters and was lowest during the first trimester. Additionally, 49.7% (n = 199) of the non-pregnant and 62.5% (n = 764) of pregnant women were iodine deficient as per the WHO criteria. While pregnancy (OR = 4.3; 95%CI: 3.08–5.96) and using non-iodised salt (OR = 1.96; 95%CI: 1.35–2.83) significantly increased the risk of iodine deficiency, the intake of iodine supplements significantly lowered the risk (OR = 0.010; 95%CI: 0.006–0.017). On the other hand, the intake of iodine above requirement was observed in 8.5% and 4.2% of the non-pregnant and pregnant women, respectively. Moreover, BMI was the sole independent factor increasing the odds (OR = 1.061; 95%CI: 1.010–1.114) of taking iodine above requirements.Conclusions This study is the first to show high prevalence of mild iodine deficiency among reproductive age Saudi women, which could represent a serious public health problem. This study also advocates the necessity to establish routine iodine dietary advice services by the health authorities to foster adequate iodine intake in pregnant women to avoid the perilous maternal-foetal health consequences of iodine deficiency.

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Women Remain at Risk of Iodine Deficiency during Pregnancy: The Importance of Iodine Supplementation before Conception and Throughout Gestation

Nutrients ◽

10.3390/nu11010172 ◽

2019 ◽

Vol 11 (1) ◽

pp. 172 ◽

Cited By ~ 8

Author(s):

Kristen Hynes ◽

Judy Seal ◽

Petr Otahal ◽

Wendy Oddy ◽

John Burgess

Keyword(s):

At Risk ◽

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Supplement Use ◽

Iodine Supplementation ◽

The Impact

In Australia, pregnant women are advised to take an iodine supplement (I-supp) (150 µg/day) to reduce risks to the foetus associated with iodine deficiency (ID). To examine the impact of this recommendation on iodine status, and to identify factors that contribute to adequacy during gestation, supplement use and Urinary Iodine Concentration (UIC) was measured in 255 pregnant women (gestation range 6 to 41 weeks) in Tasmania. The median UIC (MUIC) of 133 µg/L (Inter-quartile range 82–233) was indicative of ID, being below the 150–249 µg/L range for adequacy during pregnancy. Women taking an iodine-containing-supplement (I-supp) had a significantly higher MUIC (155 µg/L) (n = 171) compared to the combined MUIC (112.5 µg/L) (n = 84) of those who had never (120 µg/L) (n = 61) or were no longer taking an I-supp (90 µg/L) (n = 23) (p = 0.017). Among women reporting I-supp use, the MUIC of those commencing the recommended 150 µg/day prior to conception was significantly higher than those starting supplementation following pregnancy confirmation: 196 (98–315) µg/L (n = 45) versus 137.5 (82.5–233.5) µg/L (n = 124), p = 0.032. Despite recommendations for iodine supplementation pregnant Tasmanian women remain at risk of ID. Commencing an I-supp of 150 µg/day prior to conception and continuing throughout pregnancy is required to ensure adequacy. Timely advice regarding the importance of adequate iodine nutrition, including supplementation is needed to reduce the risk of irreversible in utero neurocognitive damage to the foetus.

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Prevalence of iodine deficiency and goitre during pregnancy in east Hungary

Acta Endocrinologica ◽

10.1530/eje.0.1430479 ◽

2000 ◽

pp. 479-483 ◽

Cited By ~ 16

Author(s):

E Mezosi ◽

I Molnar ◽

A Jakab ◽

E Balogh ◽

Z Karanyi ◽

...

Keyword(s):

Thyroid Gland ◽

Nutritional Status ◽

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Thyroid Volume ◽

Control Group ◽

Thyroid Function Tests ◽

Cross Sectional ◽

Nodular Goitre

OBJECTIVE: To assess the iodine nutritional status and the prevalence of goitre during pregnancy in a region of Hungary that appeared to be iodine sufficient in previous studies. DESIGN: A cross-sectional voluntary screening study was organized in which 313 pregnant women participated. METHODS: Urine iodine concentration and the volume of the thyroid gland were measured in every woman. In the presence of low urinary iodine concentrations, goitre, or both, thyroid function tests were performed. RESULTS: Iodine deficiency was found in 57.1% of the pregnant women, and was severe in 15.6%. The volume of the thyroid gland was enlarged in 19.2% of individuals. Nodular goitre was found in 17 women (5.4%). The frequency of goitre and the mean thyroid volume were increased in the group of iodine-deficient women. In the 89 cases of iodine deficiency or goitre, thyrotrophin concentrations were in the normal range; however, the free triiodothyronine:free throxine ratio was increased in 97% of them, indicating that the thyroid gland was in a stimulated state in these individuals. CONCLUSIONS: Iodine deficiency with high prevalence of goitre was recognized among pregnant women in an area that previously appeared to be iodine sufficient. An unexpected mild iodine deficiency was also noted in the non-pregnant control group. Reassessment and continuous monitoring of iodine nutritional status is warranted even in populations that are apparently considered to be 'at no risk' of iodine deficiency, especially in pregnant women. Regular administration of iodine, starting at preconception or in early pregnancy and continuing during the period of nursing, is recommended in these regions.

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

Endocrine Connections ◽

10.1530/ec-18-0131 ◽

2018 ◽

Vol 7 (5) ◽

pp. 762-767 ◽

Cited By ~ 9

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.

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