High intakes of iodine among women during pregnancy and the postpartum period has no adverse effect on thyroid function

Ju, Dal Lae; Cho, Sun Wook; Chung, Chae Won; Lee, Young Ah; Cheon, Gi Jeong; Park, Young Joo; Shin, Choong Ho; Jun, Jong Kwan; Chung, June‐Key; Park, Sue Kyung; Song, YoonJu

doi:10.1007/s00394-022-02960-6

Cited by 4 publications

(4 citation statements)

References 36 publications

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“…MIS at least 150 μg/day compared with less than 100 μg/day was associated with reduced psychomotor scores [80]. However, a recent study in Korea of 349 pregnant patients with median dietary iodine intake of 459 μg/day found no relationship to maternal thyroid function or neonatal outcomes [98]. Populations that have historically and consistently consumed high daily iodine intake may be exceptions [99].…”

Section: Iodine and Child Neurodevelopmental Outcomesmentioning

confidence: 99%

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

Nguyen

2023

Current Opinion in Endocrinology, Diabetes &Amp; Obesity

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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.

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Section: Iodine and Child Neurodevelopmental Outcomesmentioning

confidence: 99%

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

Nguyen

2023

Current Opinion in Endocrinology, Diabetes &Amp; Obesity

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“…The previously stated findings are supported by a systematic review ( n = 9 studies) and meta-analysis ( n = 8 studies) published in 2022, which found that excessive I status during pregnancy is common and related to maternal hypothyroxinemia, hypothyroidism, and hyperthyroidism along with newborn macrosomia and thyroid dysfunction [ 105 ]. Countering this, a study of 349 pregnant women in Korea with median dietary I intake during pregnancy of 459 μg/d found no relationship to maternal thyroid function and neonatal outcomes [ 106 ].…”

Section: Iodine and Offspring Neurodevelopmentmentioning

confidence: 99%

“… Hu et al. [ 106 ] Observational Korea Community at high risk of excessive intake N/A Median dietary iodine intake was above the recommended levels, but this was not related to maternal thyroid function or neonatal outcomes. Sun et al.…”

Section: Iodine and Offspring Neurodevelopmentmentioning

confidence: 99%

A Scoping Review of Iodine and Fluoride in Pregnancy in Relation to Maternal Thyroid Function and Offspring Neurodevelopment

Griebel-Thompson¹,

Sands²,

Chollet‐Hinton³

et al. 2023

Advances in Nutrition

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“…This study aimed to investigate the effects of selenium deficiency on thyroid function and pregnancy outcomes using a prospective hospital-based pregnancy cohort, known as the ideal breast milk (IBM) cohort [15,16]. The IBM cohort consists of pregnant women and their paired offspring, and its purpose is to investigate the effects of maternal nutrient status during pregnancy and lactating periods on obstetrical outcomes as well as fetal and infantile health.…”

Section: Introductionmentioning

confidence: 99%

Selenium levels and their association with thyroid autoimmunity and severe preeclampsia in pregnancy: Insights from a prospective ideal breast milk cohort study

Chung,

Kim,

Park

et al. 2024

European Thyroid Journal

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Objective: This study aimed to assess selenium status in South Korean pregnant women and impact on maternal thyroid function and pregnancy outcomes. Methods: "Ideal Breast Milk (IBM) Cohort Study" included 367 pregnant women out of 442 participants and categorized into three groups based on plasma selenium levels: deficient (<70 μg/L), suboptimal (70–99 μg/L), and optimal (≥100 μg/L). During the second or third trimester, various blood parameters, including selenium, thyroid stimulating hormone, free T4, free T3, and anti-thyroid peroxidase antibody levels, were measured. Thyroid parenchymal echogenicity was assessed as another surrogate marker for thyroid autoimmunity using ultrasonography. Results: The median plasma selenium was 98.8 (range, 46.7–206.4) μg/L, and 30 individuals (8%) were categorized as deficient, while 164 (45%) classified in the suboptimal group. Selenium deficiency was associated with markers of autoimmune thyroiditis, including positive anti-thyroid peroxidase antibody results (13.3 [deficient] vs. 4.6 [optimal] %, P=0.031) and thyroid parenchymal heterogeneity on ultrasound (33.3 [deficient] vs. 14.6 [suboptimal] vs. 17.3 [optimal] %, P=0.042), independently of gestational age. The incidence of severe preeclampsia was higher in the group not taking selenium supplements, particularly among those with twin pregnancies, compared to the group taking selenium supplements (0 [Se supplement] vs. 9.0 [No supplement] %, P=0.015). Conclusion: Pregnant women experience mild selenium deficiency, which can lead to significant health issues including maternal thyroid autoimmunity and obstetrical complications during pregnancy. Guidelines for appropriate selenium intake according to the stage of pregnancy and the number of fetuses are needed.

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High intakes of iodine among women during pregnancy and the postpartum period has no adverse effect on thyroid function

Cited by 4 publications

References 36 publications

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

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

A Scoping Review of Iodine and Fluoride in Pregnancy in Relation to Maternal Thyroid Function and Offspring Neurodevelopment

Selenium levels and their association with thyroid autoimmunity and severe preeclampsia in pregnancy: Insights from a prospective ideal breast milk cohort study

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