Research Article

Mild to moderate iodine deficiency in pregnancy: A matter of debate

Hossein Delshad and Fereidoun Azizi*

Published: 03/12/2021 | Volume 5 - Issue 1 | Pages: 018-026


During the last few decades painstaking efforts have been made to eliminate iodine deficiency through the world. Nowadays in regions where dietary iodine intake is adequate or borderline, the main focus is increasing dietary iodine supply in the target population during pregnancy and the first years of life. Severe iodine deficiency during pregnancy increases the risk of irreversible brain damage, intellectual disability, neurologic abnormalities, stunted growth, increased pregnancy loss, infant mortality, impairments in child development and cretinism. The potential effects of mild-to-moderate iodine deficiency are debated. Results from animal studies and observational human studies indicate that maternal mild-to-moderate iodine deficiency disturbs thyroid function in pregnancy and it also may affects fetal neurodevelopment. The effect of supplementation of iodine on thyroid function of pregnant women and their newborn, neurodevelopment of infants and cognitive performance of children have been investigated using iodine nutrition in pregnancy, based on median urinary iodine concentration. However they have found conflicting results regarding the benefits or harms of iodine supplementation in pregnancy. Although many epidemiological, interventional and clinical studies have supported the association between thyroid function in pregnant women and later psychomotor and mental development of their children, the effect of iodine supplementation in pregnant women on neurodevelopment of children is inconclusive. Even in areas with well-established universal salt iodization program, pregnancy could be at risk of having iodine deficiency and despite WHO/ICCIDD/UNICEF recommendation which believe that dietary iodine fortification during pregnancy depends primarily on the extent of pre-existing iodine deprivation, systematic dietary fortification needs to be implemented in this vulnerable group. However, iodine supplementation of mildly iodine deficient pregnant women may not have beneficial effects in their thyroid function or neurodevelopment of their children.

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  1. Brent GA. Mechanisms of thyroid hormone action. J Clin Invest. 2012; 122: 3035. PubMed:
  2. Mendoza A, Hollenberg AN. New insights into thyroid hormone action. Pharmacol Ther. 2017; 173: 135-145. PubMed:
  3. Flamant F, Cheng SY, Hollenberg AN, Moeller LC, Samarut J, et al. Thyroid Hormone Signaling Pathways: Time for a More Precise Nomenclature. Endocrinology. 2017; 158: 2052-2057. PubMed:
  4. Zimmermann MB. Iodine deficiency. Endocr Rev. 2009; 30: 376-408. PubMed:
  5. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2001. PubMed:
  6. Delange F. Iodine requirements during pregnancy, lactation and the neonatal period and indicators of optimal iodine nutrition. Public Health Nutr. 2007; 12A: 1571-1580. PubMed:
  7. Lombardi FAA, Pinchera A, Antonangeli L, Rago T, Chiovato L, et al. Mild iodine deficiency during fetal/neonatal life and neuropsychological impairment in Tuscany. J Endocrinol Invest. 1995; 18: 57-62. PubMed:
  8. van Mil NH, Tiemeier H, Bongers-Schokking JJ, Ghassabian, Hofman A, et al. Low urinary iodine excretion during early pregnancy is associated with alterations in executive functioning in children. J Nutr. 2012; 142: 2167-2174. PubMed:
  9. Levie D, Korevaar TIM, Bath SC, Murcia M, Dineva M, et al. Association of maternal iodine status with child IQ: A meta-analysis of individual participant data. J Clin Endocrinol Metab. 2019; 104: 5957-5967. PubMed:
  10. Gowachirapant S, Jaiswal N, Melse-Boonstra A, Galetti V, Stinca S, et al. Effect of iodine supplementation in pregnant women on child neurodevelopment: A randomized, double-blind, placebo-controlled trial. Lancet Diabetes Endocrinol. 2017; 5: 853-863. PubMed:
  11. Zhou SJ, Skeaff SA, Ruan P, Doyle LW, Anderson PJ, et al. The effect of iodine supplementation in pregnancy on early childhood neurodevelopment and clinical outcomes: Results of an aborted randomized placebo-controlled trial. Trials. 2015; 16: 563. PubMed:
  12. Fantz CR, Dagogo-Jack S, Ladenson JH, Gronowski AM. Thyroid function during pregnancy. Clin Chem. 1999; 45: 2250-2258. PubMed:
  13. Ballabio M, Poshychinda M, Ekins RP. Pregnancy-induced changes in thyroid function: role of human chorionic gonadotropin as putative regulator of maternal thyroid. J Clin Endocrinol Metab. 1991; 73: 824-831. PubMed:   
  14. Glinoer D. The regulation of thyroid function during normal pregnancy: importance of the iodine nutrition status. Best Pract Res Clin Endocrinol Metab. 2004; 18: 133–152. PubMed:
  15. Leung AM, Pearce EN, Braverman LE. Iodine nutrition in pregnancy and lactation. Endocrinol Metab Clin North Am. 2011; 40: 765-777. PubMed:
  16. Hetzel BS. Iodine deficiency disorders (IDD) and their eradication. Lancet. 1983; 2: 1126-1129. PubMed:
  17. Iodine Global Network. Global Scorecard 2020.–3-June-2020.pdf
  18. Zimmermann MB, Gizak M, Abbott K, Andersson M, Lazarus JH. Iodine deficiency in pregnant women in Europe. Lancet Diabetes Endocrinol. 2015; 3: 672–674. PubMed:
  19. Candido AC, Morais NS, Dutra LV, Pinto CA, Franceschini SDCC, et al. Insufficient iodine intake in pregnant women in different regions of the world: a systematic review. Arch Endocrinol Metab. 2019; 63: 306-311.PubMed:
  20. Perrine CG, Herrick KA, Gupta PM, Caldwell KL. Iodine Status of Pregnant Women and Women of Reproductive Age in the United States Thyroid. 2019; 29: 153-154. PubMed:
  21. Fuse Y, Shishiba Y, Irie M. Gestational changes of thyroid function and urinary iodine in thyroid antibody-negative Japanese women. Endocr J. 2013; 60; 1095-1106. PubMed:
  22. Delshad H, Touhidi M, Abdollahi Z, Hedayati M, Salehi F, et al. Inadequate iodine nutrition of pregnant women in an area of iodine sufficiency. J Endocrinol Invest. 2016; 39: 755–762. PubMed:
  23. Lindorfer H, Krebs M, Kautzky-Willer A, Bancher-Todesca D, Sager M, et al. Iodine deficiency in pregnant women in Austria.  Eur J Clin Nutr. 2015; 69: 349-354. PubMed:
  24. Knight BA, Shields BM, He X, Pearce EN, Braverman LE, et al. Iodine deficiency amongst pregnant women in South-West England. Clin Endocrinol (Oxf). 2017; 86: 451-455. PubMed:
  25. Henjum S, Aakre I, Lilleengen AM, Garnweidner-Holme L, Borthne S, et al. Suboptimal Iodine Status among Pregnant Women in the Oslo Area, Norway. Nutrients. 2018; 10: 280. PubMed:
  26. Tuccilli C, Baldini E, Truppa E, D’Auria B, De Quattro D, et al. Iodine deficiency in pregnancy: Still a health issue for the women of Cassino city, Italy.  Nutrition. 2018; 50: 60-65. PubMed:
  27. Manousou S, Andersson M, Eggertsen R, Hunziker S, Hulthén L, et al. Iodine deficiency in pregnant women in Sweden: a national cross-sectional study. Eur J Nutri. 2020; 59: 2535–2545. PubMed:
  28. Chan S, Kachilele S, McCabe CJ, et al. Early expression of thyroid hormone deiodinases and receptors in human fetal cerebral cortex. Brain Res Dev Brain Res. 2002; 138: 109-116. PubMed:
  29. Forhead AJ, Fowden AL. Thyroid hormones in fetal growth and prepartum maturation. J Endocrinol. 2014; 221: R87–R103. PubMed:
  30. Haddow JE, Palomaki GE, Allan WC, Williams JR, Knight GJ, et al. Maternal thyroid deficiency during pregnancy and subsequent neuropsychological development of the child. New Engl J Med. 1999; 341:549–555. PubMed:
  31. Pop VJ, Brouwers EP, Vader HL, Vulsma T, van Baar AL, et al. Maternal hypothyroxinaemia during early pregnancy and subsequent child development: a 3-year follow-up study. Clin Endocrinol (Oxf). 2003; 59:282–288. PubMed:
  32. Allan WC, Haddow JE, Palomaki GE, Williams JR, Mitchell ML, et al. Maternal thyroid deficiency and pregnancy complications: implications for population screening. J Med Screen. 2000; 7: 127–130. PubMed:
  33. Casey BM, Dashe JS, Wells CE, McIntire DD, Byrd W, et al. Subclinical hypothyroidism and pregnancy outcomes. Obstet Gynecol. 2005; 105: 239–245. PubMed:
  34. Korevaar TI, Schalekamp-Timmermans S, de Rijke YB, et al. Hypothyroxinemia and TPO-antibody positivity are risk factors for premature delivery: the Generation R Study. J Clin Endocrinol Metab. 2013; 98: 4382–4390. PubMed:
  35. Stagnaro-Green A, Chen X, Bogden JD, Davies TF, Scholl TO. The thyroid and pregnancy: a novel risk factor for very preterm delivery. Thyroid. 2005; 15: 351–357. PubMed:
  36. Shields BM, Knight BA, Hill A, Hattersley AT, Vaidya B. Thyroid hormone level at birth is associated with fetal growth. J Clin Endocrinol Metab. 2011; 96: E934–E938. PubMed:
  37. Medici M, Timmermans S, Visser W, de Muinck Keizer-Schrama S, Jaddoe V, et al. Maternal thyroid hormone parameters during early pregnancy and birth weight: the Generation R Study. J Clin Endocrinol Metab. 2013; 98:59–66. PubMed:  
  38. Casey BM, Leveno KJ. Thyroid disease in pregnancy. Obstetr Gynecol. 2013; 108: 1283–1292. PubMed:
  39. Männistö T, Vääräsmäki M, Pouta A, Hartikainen AL, Ruokonen, et al. Perinatal outcome of children born to mothers with thyroid dysfunction or antibodies: a prospective population-based cohort study. J Clin Endocrinol Metab. 2009; 94: 772–779. PubMed:
  40. Sahu MT, Das V, Mittal S, Agarwal A, Sahu M. Overt and subclinical thyroid dysfunction among Indian pregnant women and its effect on maternal and fetal outcome. Arch Gynecol Obstet. 2010; 281: 215–220. PubMed:
  41. León  G, Murcia M, Rebagliato M, Álvarez-Pedrerol M, Castilla, et al. Maternal thyroid dysfunction during gestation, preterm delivery, and birth weight. The Infancia y Medio Ambiente Cohort, Spain Paediatr Perinat Epidemiol. 2015; 29: 113-122. PubMed:
  42. Taylor PN, Lazarus JH. Hypothyroidism in Pregnancy. Endocrinol Metab Clin North Am. 2019; 48: 547-556. PubMed:
  43. Patel J, Landers K, Li H, Mortimer RH, K Richard. Thyroid hormones and fetal neurological development. J Endocrinol. 2011; 209: 1–8. PubMed:
  44. Kester MH, de Mena RM, Obregon MJ. Iodothyronine levels in the human developing brain: major regulatory roles of iodothyronine deiodinases in different areas. J Clin Endocrinol Metab. 2004; 89: 3117-3128. PubMed:  
  45. Morreale de Escobar G, Obregon MJ, Escobar del Ray F. Maternal thyroid hormones early in pregnancy and fetal brain development. Best Pract Res Clin Endocrinol Metab. 2004; 18: 225–248. PubMed:
  46. Fisher DA, Polk DH. Development of the thyroid.  Baillieres Clin Endocrinol Metab. 1989; 3: 627-657. PubMed:
  47. Ittermann T,  Albrecht D, Arohonka P,  Bilek R, J. de Castro J. Standardized Map of Iodine Status in Europe. Thyroid. 2020; 30: 1346–1354. PubMed:
  48. WHO Secretariat, Andersson M, de Benoist B, Delange F, Zupan J. Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr. 2007; 10: 1606–1611. PubMed:
  49. WHO/UNICEF. Reaching optimal iodine nutrition in pregnant and lactating women and young children. Joint Statement by the WHO and the UNICEF. World Health Organization, Geneva. 2007.
  50. Pearce EN, Lazarus JH, Moreno-Reyes R, Zimmermann MB. Consequences of iodine deficiency and excess in pregnant women: an overview of current knowns and unknowns. Am J Clin Nutr. 2016; 104: 918s–923s. PubMed:
  51. Zhou SJ, Anderson AJ, Gibson RA, Makrides M. Effect of iodine supplementation in pregnancy on child development and other clinical outcomes: a systematic review of randomized controlled trials. Am J Clin Nutrit. 2013; 98: 1241–1254. PubMed:
  52. Magri F, Zerbini F, Gaiti M, Capelli V, Croce, S, et al. Poverty and immigration as a barrier to iodine intake and maternal adherence to iodine supplementation. J Endocrinol Invest. 2019; 42: 435–442. PubMed:
  53. Berg V, Nost TH, Skeie G, Thomassen Y, Berlinger B, et al. Thyroid homeostasis in mother-child pairs in relation to maternal iodine status: the MISA study. Eur J Clin Nutr. 2017; 71: 1002–1007. PubMed:
  54. Kemp WN. Iodine deficiency in relation to the stillbirth problem. Can Med Assoc J. 1939; 41: 356–361. PubMed:
  55. Dillon JC, Milliez J. Reproductive failure in women living in iodine deficient areas of West Africa. BJOG. 2000; 107: 631–636. PubMed:  
  56. Yang J, Liu Y, Liu H, Zheng H, Li X, et al. Associations of maternal iodine status and thyroid function with adverse pregnancy outcomes in Henan Province of China. J Trace Elem Med Biol. 2018; 47: 104–110. PubMed:
  57. Mills JL, Ali M, Buck Louis GM, Kannan K, Weck J, et al. Pregnancy loss and iodine status: the LIFE prospective cohort study. Nutrients. 2019; 11: 534. PubMed:
  58. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPACE). Lancet. 2013; 382: 331-337. PubMed:  
  59. Smyth PP, Hetherton AM, Smith DF, Radcliff M, O’Herlihy C. Maternal iodine status and thyroid volume during pregnancy: correlation with neonatal iodine intake. J Clin Endocrinol Metab. 1997; 82: 2840–2843. PubMed:
  60. Sahin SB, Ogullar S, Ural UM, Ilkkilic K, Metin Y, (2014) Alterations of thyroid volume and nodular size during and after pregnancy in a severe iodine-deficient area. Clin Endocrinol. 81: 762–768. PubMed:
  61. Glinoer D. Clinical and biological consequences of iodine deficiency during pregnancy. Endocr Dev. 2007; 10: 62-85. PubMed:
  62. Liesenkotter KP, Gopel W, Bogner U, Stach B, Gruters A. Earliest prevention of endemic goiter by iodine supplementation during pregnancy. Eur J Endocrinol. 1996; 134: 443–448. PubMed:
  63. Moleti M, Lo Presti VP, Campolo MC, Mattina F, Galletti M, et al. Iodine prophylaxis using iodized salt and risk of maternal thyroid failure in conditions of mild iodine deficiency. J Clin Endocrinol Metab. 2008; 93: 2616–2621. PubMed:
  64. Moleti M, Di Bella B, Giorgianni G, Mancuso A, De Vivo A, et al. Maternal thyroid function in different conditions of iodine nutrition in pregnant women exposed to mild-moderate iodine deficiency: an observational study. Clin Endocrinol. 2011; 74: 762–768. PubMed:
  65. Zimmermann MB. The role of iodine in human growth and development. Semin Cell Dev Biol. 2011; 22: 645–652. PubMed:
  66. Snart CJP, Keeble C, Taylor E, Cade JE, Stewart PM, et al. Maternal iodine status and associations with birth outcomes in three major cities in the United Kingdom. Nutrients. 2019; 11: 441. PubMed:
  67. Charoenratana C, Leelapat P, Traisrisilp K, Tongsong T. Maternal iodine insufficiency and adverse pregnancy outcomes. Matern Child Nutr. 2015; 12: 680-687. PubMed:
  68. Alvarez-Pedrerol M, Guxens M, Mendez M, Canet Y, Martorell R, et al. Iodine levels and thyroid hormones in healthy pregnant women and birth weight of their offspring. Eur J Endocrinol. 2009; 160: 423–429. PubMed:  
  69. Abel MH, Korevaar TIM, Erlund I, Villanger GD, Caspersen IH, et al. Iodine intake is associated with thyroid function in mild to moderately iodine deficient pregnant women. Thyroid. 2018; 28: 1359–1371. PubMed:
  70. Levie D, Derakhshan A, Shu H, Broeren M, de Poortere R, et al. The association of maternal iodine status in early pregnancy with thyroid function in the SELMA study. Thyroid. 2019; 29: 1660-1668. PubMed:
  71. Farebrother J, Naude CE, Nicol L, Sang Z, Yang Z, et al. Effects of Iodized Salt and Iodine Supplements on Prenatal and Postnatal Growth: A Systematic Review. Adv Nutr. 2018; 9: 219-237. PubMed:
  72. Abel MH, Caspersen IH, Sengpiel V. Insufficient maternal iodine intake is associated with sub-fecundity, reduced fetal growth, and adverse pregnancy outcomes in the Norwegian Mother, Father and Child Cohort Study BMC Med. 2020; 18: 211. PubMed:  
  73. Lazarus J, Brown RS, Daumerie C, Hubalewska-Dydejczyk A, Negro R, et al. 2014 European thyroid association guidelines for the management of subclinical hypothyroidism in pregnancy and in children. Eur Thyroid J. 2014; 3: 76–94. PubMed:
  74. Moog NK, Entringer S, HeimC,Wadhwa PD, Kathmann N, Buss C. Influence of maternal thyroid hormones during gestation on fetal brain development. Neuroscience. 2017; 342: 68–100. PubMed:
  75. Mohan V, Sinha RA, Pathak A, Rastogi L, Kumar P, et al. Maternal thyroid hormone deficiency affects the fetal neocorticogenesis by reducing the proliferating pool, rate of neurogenesis and indirect neurogenesis. Exp Neurol. 2012; 237: 477–488. PubMed:
  76. Pop VJ, Kuijpens JL, van Baar AL, Verkerk G, van Son MM, et al. Low maternal free thyroxin concentrations during early pregnancy are associated with impaired psychomotor development in infancy. Clin Endocrinol (Oxf). 1999; 50: 149-155. PubMed:
  77. Pharoah POD, Buttfield IH, Hetzel BS. Neurological damage to the fetus resulting from severe iodine deficiency during pregnancy. Lancet. 1971; 297:308–310. PubMed:
  78. Cao XY, Jiang XM, Dou ZH, Rakeman MA, Zhang ML, O’Donnell KJ, et al. Timing of vulnerability of the brain to iodine deficiency in endemic cretinism. N Engl J Med. 1974; 331:1739–1744. PubMed:
  79. Torlinska B, Bath SC, Janjua A, Boelaert K, Chan SY. Iodine status during pregnancy in a region of mild-to-moderate iodine deficiency is not associated with adverse obstetric outcomes; results from the Avon Longitudinal Study of Parents And Children (ALSPAC). Nutrients. 2018; 10: 291. PubMed:
  80. Hynes KL, Otahal P, Hay I, Burgess JR. Mild iodine deficiency during pregnancy is associated with reduced educational outcomes in the offspring: 9-year follow-up of the Gestational Iodine Cohort. J Clin Endocrinol Metab. 2013; 98: 1954-1962. PubMed:
  81. Abel MH, Caspersen IH, Meltzer HM, Haugen M, Brandlistuen RE, et al. Suboptimal maternal iodine intake is associated with impaired child neurodevelopment at 3 years of age in the Norwegian Mother and Child Cohort Study. J Nutr. 2017; 147: 1314–1324. PubMed:
  82. Markhus MW, Dahl L, Moe V, Abel MH, Brantsæter AL, et al. Maternal Iodine Status is Associated with Offspring Language Skills in Infancy and Toddlerhood. Nutrients. 2018; 10: 1270. PubMed:
  83. Iodine Global Network. Global scorecard of iodine nutrition in 2017 in the general population based on school-age children (SAC) with additional data for pregnant women (PW) [Internet]. Zurich, Switzerland: Iodine Global Network. 2017.
  84. Rebagliato M, Murcia M, Alvarez-Pedrerol M, Espada M, Fernández-Somoano A, et al. Iodine supplementation during pregnancy and infant neuropsychological development. INMA Mother and Child Cohort Study.  Am J Epidemiol. 2013; 177: 944-953. PubMed:
  85. Berbel P, Mestre JL, Santamaría A, Palazón I, Franco A, et al. Delayed neurobehavioral development in children born to pregnant women with mild hypothyroxinemia during the first month of gestation: the importance of early iodine supplementation. Thyroid. 2009; 19: 511–519. PubMed:
  86. Velasco I, Carreira M, Santiago P, Muela JA, García-Fuentes E, et al. Effect of iodine prophylaxis during pregnancy on neurocognitive development of children during the first two years of life. J Clin Endocrinol Metab. 2009; 94: 3234–3241. PubMed:
  87. Zhou SJ, Anderson AJ, Gibson RA, Makrides M. (2013) Effect of iodine supplementation in pregnancy on child development and other clinical outcomes: a systematic review of randomized controlled trials. Am J Clin Nutr. 2013; 98: 1241–1254. PubMed:
  88. Chaouki ML, Benmiloud M. Prevention of iodine deficiency disorders by oral administration of lipiodol during pregnancy. Eur J Endocrinol. 1994; 130: 547–551. PubMed:
  89. Qian M, Wang D, Watkins WE, Gebski V, Yan YQ, et al. The effects of iodine on intelligence in children: a meta-analysis of studies conducted in China Asia Pac J Clin Nutr. 2005; 14: 32-42. PubMed:
  90. Censi S, Watutantrige-Fernando S, Groccia G, Manso J, Plebani M, et al. The Effects of Iodine Supplementation in Pregnancy on Iodine Status, Thyroglobulin Levels and Thyroid Function Parameters: Results from a Randomized Controlled Clinical Trial in a Mild-to-Moderate Iodine Deficiency Area.  Nutrients. 2019; 11: 2639. PubMed:
  91. Taylor PN, Okosieme OE, Dayan CM, Lazarus JH. Therapy of endocrine disease: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis. Eur J Endocrinol. 2013; 170: R1-R15. PubMed:
  92. Rebagliato M, Murcia M, Espada M, Alvarez-Pedrerol M, Bolumar F, et al. Iodine intake and maternal thyroid function during pregnancy. Epidemiology. 2010; 21: 62–69. PubMed:
  93. Mohammed H, Marquis GS, Aboud F, Bougma K, Samuel A.  Pre-pregnancy Iodized Salt Improved Children’s Cognitive Development in Randomized Trial in Ethiopia. Matern Child Nutr Jul. 2020; 16: e12943. PubMed:  
  94. Fishpool MDH, Rayman MP, Mendis J, Bath SC. Systematic Review and Meta-Analysis of the Effects of Iodine Supplementation on Thyroid Function and Child Neurodevelopment in Mildly-To-Moderately Iodine-Deficient Pregnant Women. Am J Clin Nutr. 2020; 112: 389-412. PubMed:
  95. Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AG. Iodine-Induced hypothyroidism. Thyroid. 2001; 11: 501-510. PubMed:
  96. Shi X, Han C, Li C, Mao J, Wang W, et al. Optimal and safe upper limits of iodine intake for early pregnancy in iodine-sufficient regions: a cross-sectional study of 7190 pregnant women in China. J Clin Endocrinol Metab. 2015; 100: 1630–1633. PubMed:
  97. De Groot L, Abalovich M, Alexander EK. Management of thyroid dysfunction during pregnancy and postpartum: an endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2012; 97: 2543–2565. PubMed:
  98. Institute of Medicine Food and Nutrition Board. Dietary Reference Intakes. Washington (DC): National Academies Press; 2006.
  99. WHO. Iodine supplementation in pregnant and lactating women. Geneva: World Health Organization; 2016.
  100. Andersson M, de Benoist B, DelangeF, Zupan J. WHO Secretariat. Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr. 2007; 10: 1606-1611. PubMed:  
  101. Romano R, Jannini EA, Pepe M, Grimaldi A, Olivieri M, et al. The effects of iodoprophylaxis on thyroid size during pregnancy. Am J Obstet Gynecol. 1991; 164: 482–485. PubMed:
  102. Pedersen KM , Laurberg P, Iversen E, Knudsen PR, Gregersen HE, et al. Amelioration of some pregnancy-associated variations in thyroid function by iodine supplementation. J Clin Endocrinol Metab. 1993; 77:1078–1083. PubMed:
  103. Fierro-Benitez R, Cazar R, Stanbury JB, Rodriguez P, Garces F, et al. Effects on schoolchildren of prophylaxis of mother with iodized oil in an area of iodine deficiency. J Endocrinol Inves. 1988; 11: 327-335. PubMed:
  104. Glinoer D, De Nayer P, Delange F, Lemone M, Toppet V, et al. A randomized trial for the treatment of mild iodine deficiency during pregnancy: maternal and neonatal effects. J Clin Endocrinol Metab. 1995; 80: 258–262. PubMed:
  105. Becker DV, Braverman LE, Delange F, Hollowell JG, Lamm SH, et al. Iodine supplementation for pregnancy and lactation—United States and Canada: recommendations of the American Thyroid Association. Thyroid. 2006; 16: 949–995. PubMed:
  106. WHO Secretariat, Andersson M, de Benoist B, Delange F, Zupan J. Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr. 2007; 10:1606–1611. PubMed:
  107. WHO/UNICEF. Reaching optimal iodine nutrition in pregnant and lactating women and young children. Joint Statement by the WHO and the UNICEF. World Health Organization, Geneva. 2007.
  108. International Council for Control of Iodine Deficiency Disorders. Iodine requirements in pregnancy and infancy. IDD Newsletter. 2007; 23: 1-2.
  109. Alexander EK, Pearce EN, Brent GA, Brown RS, Chen H, et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid. 2017; 27: 315-389. PubMed:
  110. De Groot L, Abalovich M, Alexander EK, Amino N, Barbour L, et al. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2012; 97: 2543-2565. PubMed: