Effect of iodine supplementation in pregnancy on neurocognitive development on offspring in iodine deficiency areas: a systematic review

Machamba, Almeida Abudo Leite; Azevedo, Francilene Maria; Fracalossi, Karen O.; Franceschini, Sylvia do Carmo Castro

doi:10.20945/2359-3997000000376

“…A positive association between preconception maternal iodine status and the cognitive function of the offspring at the age of 6–7 years could be demonstrated [ 265 ]. In contrast, meta-analyses of iodine supplementation starting during pregnancy found no effect on child neurodevelopment [ 196 , 264 , 269 , 270 , 271 , 272 ]. The lack of beneficial effects of iodine supplementation, typically after the first trimester, bypasses the critical period of development early in gestation.…”

Section: Resultsmentioning

confidence: 99%

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review

Großklaus

¹

,

Liesenkötter

²

,

Doubek³

et al. 2023

Nutrients

6

0

View full text Add to dashboard Cite

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. An additional threat to the thyroid hormone system is the ubiquitous exposure to endocrine disrupters, which might exacerbate the effects of iodine deficiency in pregnant women on the neurocognitive development of their offspring. Ensuring adequate iodine intake is therefore essential not only for healthy fetal and neonatal development in general, but it might also extenuate the effects of endocrine disruptors. Individual iodine supplementation of women of childbearing age living in areas with mild to moderate iodine deficiency is mandatory as long as worldwide universal salt iodization does not guarantee an adequate iodine supply. There is an urgent need for detailed strategies to identify and reduce exposure to endocrine disrupters according to the “precautional principle”.

show abstract

“…A 2021 systematic review evaluating three RCTs [60,77,78] and one nonrandomized trial [76] and four observational cohorts [77][78][79][80] found no significant improvement in children's mental development index and behavioral development index in the supplemented group [81]. Psychomotor development index showed improvement in the poorer gross motor skills and differences in response time to sound in the supplemented group [81].…”

Section: Maternal Iodine Supplementation and Child Neurodevelopmental...mentioning

confidence: 99%

“…A 2021 systematic review evaluating three RCTs [60,77,78] and one nonrandomized trial [76] and four observational cohorts [77][78][79][80] found no significant improvement in children's mental development index and behavioral development index in the supplemented group [81]. Psychomotor development index showed improvement in the poorer gross motor skills and differences in response time to sound in the supplemented group [81]. A 2021 meta-analysis of three trials [60,77,82] found no differences observed in cognitive, language, or motor development and did not demonstrate any clear benefit on infant neurocognitive outcomes with MIS of MMID patients [57 && ].…”

Section: Maternal Iodine Supplementation and Child Neurodevelopmental...mentioning

confidence: 99%

An update: maternal iodine supplementation, thyroid function tests, and child neurodevelopmental outcomes

Nguyen

¹

2023

Current Opinion in Endocrinology, Diabetes &Amp; Obesity

1

0

View full text Add to dashboard Cite

Purpose of review The impact of maternal iodine supplementation (MIS) during pregnancy on thyroid function and child neurodevelopmental outcomes in areas of mild-to-moderate iodine deficiency (MMID) remains unclear. Recent findings Despite growing success of salt iodization programs, a 2022 meta-analysis found that 53% of pregnant patients worldwide continue to have insufficient iodine intake during pregnancy. A 2021 randomized controlled trial (RCT) found that MIS in women with mild iodine deficiency led to iodine sufficiency and positive effects on maternal thyroglobulin. A 2021 cohort study of MIS initiated prior to pregnancy was associated with lower thyroid-stimulating hormone (TSH), higher FT3, and FT4. Other cohort studies, however, found that neither salt iodization nor MIS were adequate to meet pregnancy iodine needs. Data have been mixed regarding maternal iodine status and pregnancy outcomes in patients of MMID. Meta-analyses have not shown any clear benefit on infant neurocognitive outcomes with MIS of MMID patients. A 2023 meta-analysis found that the prevalence of excess iodine intake in pregnancy was 52%. Summary MMID continues to exist during pregnancy. Salt iodization alone may be insufficient to ensure adequate iodine status during pregnancy. There is an absence of high-quality data to support routine MIS in areas of MMID. However, patients with specialized diets (vegan, nondairy, no seafood, noniodized salt, and so on) may be at risk for inadequate iodine status in pregnancy. Excess iodine intake can be detrimental to the fetus and should be avoided during pregnancy.

show abstract

“…Iodine is an indispensable nutrient for the synthesis of the thyroid hormones, triiodothyronine and thyroxine, necessary for normal growth, development, and metabolism during pregnancy, childhood, and throughout life [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Iodine Concentration in Drinking Water in the Same or Different Seasons of the Year in Brazilian Macroregions

Pinto

¹

,

Morais

²

,

Franceschini

³

et al. 2022

Journal of Nutrition and Metabolism

2

0

View full text Add to dashboard Cite

Objective. The aim of this study was to compare the concentration of iodine in drinking water in the same or different seasons of the year in Brazilian macroregions. Method. Water samples were collected from the Basic Health Units of eight municipalities that make up the different Brazilian macroregions and the Federal District. Sample collection took place in the summer, autumn, winter, and spring seasons. The spectrophotometric method with “leuco crystal violet” was used to determine the concentration of iodine in the water. Descriptive statistics on the data were performed. To verify if there was a difference in the concentration of iodine in the water between the climatic seasons of the year in the same place and between the same seasons in different locations, the Mann–Whitney or Kruskal–Wallis test was used and a p < 0.05 value was considered significant. Results. Among the climatic seasons throughout the year in the same location, there was a difference in the concentration of iodine in the water in the municipality of Pinhais, state of Paraná/South macroregion, between autumn and summer ( p = 0.041 ) and winter and summer seasons ( p = 0.003 ). There was a difference in the concentration of iodine in the water in the summer season between the Midwest and South macroregions; Northeast and Midwest, Southeast and South; North and Midwest, Southeast and South ( p < 0.05 ). In the autumn season, there was a difference in the concentration of iodine in the water between the Midwest and South macroregions; Northeast and Midwest, Southeast and South; North and Midwest, Northeast and South ( p < 0.05 ). In the winter season, there was a difference in the concentration of iodine in the water between the Southeast and Midwest and Southeast and South macroregions ( p < 0.05 ). In the spring season, there was a difference in the concentration of iodine in the water between the Southeast and Midwest and Southeast and South macroregions ( p < 0.05 ). Conclusion. There were differences in the iodine concentrations in drinking water in different locations in Brazil, when analyzed in the same seasons, and in the municipality of Pinhais between the autumn and summer and winter and summer seasons. Thus, it is suggested to monitor the iodine concentrations in water, considering the differences in climate, characteristics of each region, and soils throughout the Brazilian territory, since the deficiency or excess of iodine can bring risks to the health of the population.

show abstract

Effect of iodine supplementation in pregnancy on neurocognitive development on offspring in iodine deficiency areas: a systematic review

Cited by 8 publications

References 28 publications

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review

An update: maternal iodine supplementation, thyroid function tests, and child neurodevelopmental outcomes

Iodine Concentration in Drinking Water in the Same or Different Seasons of the Year in Brazilian Macroregions

Contact Info

Product

Resources

About