Effects of iodine supplementation during pregnancy on child growth and development at school age

O’Donnell, Karen; Rakeman, Murdon Abdul; Zhi-Hong, Dou; Mei, Zeng Yong; DeLong, N; Brenner, Gerald; Ma, Tai; Wang, Dong; DeLong, G. Robert

doi:10.1111/j.1469-8749.2002.tb00291.x

Cited by 27 publications

(24 citation statements)

References 14 publications

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“…Our results indicating improved performance on VEXP Overall Percentage Anticipatory Saccades at 5 months with better maternal iodine status are consistent with previous studies of iodine supplementation (O'Donnell, et al, 2002).…”

Section: Discussionsupporting

confidence: 82%

Neurodevelopmental effects of maternal nutritional status and exposure to methylmercury from eating fish during pregnancy

et al. 2008

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Fish contain nutrients that promote optimal brain growth and development but also contain methylmercury (MeHg) that can have toxic effects. The present study tested the hypothesis that the intake of selected nutrients in fish or measures of maternal nutritional status may represent important confounders when estimating the effects of prenatal methylmercury exposure on child development. The study took place in the Republic of Seychelles, an Indian Ocean archipelago where fish consumption is high. A longitudinal cohort study design was used. A total of 300 mothers were enrolled early in pregnancy. Nutrients considered to be important for brain development were measured during pregnancy along with prenatal MeHg exposure. The children were evaluated periodically to age 30 months. There were 229 children with complete outcome and covariate data for analysis. The primary endpoint was the Bayley Scales of Infant Development-II (BSID-II), administered at 9 and 30 months of age. Combinations of four secondary measures of infant cognition and memory were also given at 5, 9 and 25 months. Cohort mothers consumed an average of 537 gm of fish (9 meals containing fish) per week. The average prenatal MeHg exposure was 5.9 ppm in maternal hair. The primary analysis examined the associations between MeHg, maternal nutritional measures and children's scores on the BSID-II and showed an adverse association between MeHg and the mean Psychomotor Developmental Index (PDI) score at 30 months. Secondary analyses of the association between the PDI and only MeHg alone or nutritional factors alone showed only a borderline significant association between MeHg and the PDI at 30 months and no associations with nutritional factors. One experimental measure at 5 months of age was positively associated with iodine status, but not prenatal MeHg exposure. These findings suggest a possible confounding role of maternal nutrition in studies examining associations between prenatal MeHg exposures and developmental outcomes in children.

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Section: Discussionsupporting

confidence: 82%

Neurodevelopmental effects of maternal nutritional status and exposure to methylmercury from eating fish during pregnancy

et al. 2008

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“…In both studies where assessed, neurodevelopmental outcomes were improved in children from mildly to moderately iodine-deficient areas whose mothers received iodine supplementation early in pregnancy (148,154). The timing of supplementation is likely to be critical because the beneficial effects of iodine on offspring development appeared to be lost if supplementation is started after 10-20 weeks gestation.…”

Section: Question 46: Does Iodine Supplementation In Pregnancy and Lamentioning

confidence: 99%

“…In areas of severe iodine deficiency, iodine supplementation of mothers prior to conception or in early pregnancy results in children with improved cognitive performance relative to those given a placebo (147)(148)(149). The prevalence of cretinisim and other severe neurological abnormalities is significantly reduced (150).…”

Section: Clinical Guidelines For Iodine Nutritionmentioning

confidence: 99%

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

Alexander

Pearce

Brent

et al. 2017

Thyroid

2,006

2,716

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INTRODUCTION Pregnancy has a profound impact on the thyroid gland and thyroid function. The gland increases 10% in size during pregnancy in iodine-replete countries and by 20%-40% in areas of iodine deficiency. Production of thyroxine (T 4 ) and triiodothyronine (T 3 ) increases by 50%, along with a 50% increase in the daily iodine requirement. These physiological changes may result in hypothyroidism in the later stages of pregnancy in iodine-deficient women who were euthyroid in the first trimester. The range of thyrotropin (TSH), under the impact of placental human chorionic gonadotropin (hCG), is decreased throughout pregnancy with the lower normal TSH level in the first trimester being poorly defined and an upper limit of 2.5 mIU/L. Ten percent to 20% of all pregnant women in the first trimester of pregnancy are thyroid peroxidase (TPO) or thyroglobulin (Tg) antibody positive and euthyroid. Sixteen percent of the women who are euthyroid and positive for TPO or Tg antibody in the first trimester will develop a TSH that exceeds 4.0 mIU/L by the third trimester, and 33%-50% of women who are positive for TPO or Tg antibody in the first trimester will develop postpartum thyroiditis. In essence, pregnancy is a stress test for the thyroid, resulting in hypothyroidism in women with limited thyroidal reserve or iodine deficiency, and postpartum thyroiditis in women with underlying Hashimoto's disease who were euthyroid prior to conception.Knowledge regarding the interaction between the thyroid and pregnancy/the postpartum period is advancing at a rapid pace. Only recently has a TSH of 2.5 mIU/L been accepted as the upper limit of normal for TSH in the first trimester. This has important implications in regards to interpretation of the literature as well as a critical impact for the clinical diagnosis of hypothyroidism. Although it is well accepted that overt hypothyroidism and overt hyperthyroidism have a deleterious impact on pregnancy, studies are now focusing on the potential impact of subclinical hypothyroidism and subclinical hyperthyroidism on maternal and fetal health, the association between miscarriage and preterm delivery in euthyroid women positive for TPO and/or Tg antibody, and the prevalence and long-term impact of postpartum thyroiditis. Recently completed prospective randomized studies have begun to produce critically needed data on the impact of treating thyroid disease on the mother, fetus, and the future intellect of the unborn child.It is in this context that the American Thyroid Association (ATA) charged a task force with developing clinical guidelines on the diagnosis and treatment of thyroid disease during pregnancy and the postpartum. The task force consisted of international experts in the field of thyroid disease and pregnancy, and included representatives from the ATA, Asia and Oceania Thyroid Association, Latin American Thyroid Society, American College of Obstetricians and Gynecologists, and the Midwives Alliance of North America. Inclusion of thyroidologists, obstetricians, and midwives ...

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“…O'Donnell KJ et al [93] in their study published in 2002 evaluated growth and development of 689 children (range 4 to 7.3 years whose mothers received iodine during pregnancy, and children who received iodine first in their 2nd year) in a part of China's Province which has the lowest levels of iodine in water and soil ever recorded. Head circumference but not height was improved for those whose mothers received iodine during pregnancy (compared with those receiving iodine at age 2) and for those supplemented before the end of the 2nd trimester (relative to those supplemented during the 3rd trimester).…”

Section: Interventions Using Iodinementioning

confidence: 99%

11 Hypothyroidism in Pregnancy

Lazarus¹,

Pīrāgs²,

Butz³

2009

The Thyroid and Reproduction

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Effects of iodine supplementation during pregnancy on child growth and development at school age

Cited by 27 publications

References 14 publications

Neurodevelopmental effects of maternal nutritional status and exposure to methylmercury from eating fish during pregnancy

Neurodevelopmental effects of maternal nutritional status and exposure to methylmercury from eating fish during pregnancy

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

11 Hypothyroidism in Pregnancy

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