Effect of Maternal Iodine Excess during Pregnancy on Neonatal Thyroid Function and Neurodevelopmental Status at 12 Weeks
DOI:
https://doi.org/10.15605/jafes.039.02.12Keywords:
thyroid, hypothyroidism, iodinization, hyperthyrotropinemia, thyroid function test, urine iodine concentrationAbstract
Objective. This study aims to determine the effect of iodine excess in pregnant mothers on thyroid function, growth and neurodevelopment in the neonates when assessed at 12 weeks of age.
Methodology. This prospective study enrolled term neonates with birth weight >2500 gm of mothers having urine iodine concentration (UIC) ≥500 µg/L documented in the third trimester of the peripartum period. Neonatal TSH was collected by heel prick on dried blood spots within 24-72 hours of age and measured by time-resolved fluroimmunoassay. Neonates with TSH ≥11 mIU/L at birth were followed up at 2 and 12 weeks to monitor thyroid dysfunction, growth and development.
Results. A total of 2354 (n = 1575 in the delivery room) maternal urine samples were collected of which 598 (25.4%) had elevated UIC. Forty-nine (12.2%) neonates had TSH ≥11mIU/L on newborn screening of whom 18 and 3 neonates had residual elevated TSH at 2 and 12 weeks of life, respectively. Maternal iodine levels correlated weakly with TSH at 2 weeks (rho = 0.299; p = 0.037). No child required treatment for congenital hypothyroidism. Eight babies additionally had TSH >5 mIU/L at 12 weeks of life. The growth and development of babies with or without TSH elevation was comparable at three months (p >0.05).
Conclusion. Maternal iodine excess in pregnancy and peripartum period causes transient hyperthyrotropinemia in neonates that did not affect the growth and development at 3 months of age.
Downloads
References
Marwaha RK, Tandon N, Garg MK, et al. Thyroid status two decades after salt iodization: country-wide data in school children from India. Clin Endocrinol. 2012;76(6):905-10. https://pubmed.ncbi.nlm.nih.gov/22142266 https://doi.org/10.1111/j.1365-2265.2011.04307.x
Abbag FI, Abu-Eshy SA, Mahfouz AA, et al. Iodine deficiency disorders in the Aseer region, south-western Saudi Arabia: 20 years after the national survey and universal salt iodization. Public Health Nutr. 2015;18(14):2523-9. https://pubmed.ncbi.nlm.nih.gov/25563504 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10271673 https://doi.org/10.1017/S1368980014003073
Zhao W, Han C, Shi X, et al. Prevalence of goiter and thyroid nodules before and after implementation of the universal salt iodization program in mainland China from 1985 to 2014: a systematic review and meta-analysis. PLoS ONE. 2014;9(10):e109549. https://pubmed.ncbi.nlm.nih.gov/25313993 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4196906 https://doi.org/10.1371/journal.pone.0109549
Tan L, Sang Z, Shen J, et al. Prevalence of thyroid dysfunction with adequate and excessive iodine intake in Hebei Province, People’s Republic of China. Public Health Nutr. 2015; 18(9):1692-7. https://pubmed.ncbi.nlm.nih.gov/25373938 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10271343 https://doi.org/10.1017/S1368980014002237
Fiore E, Tonacchera M, Vitti P. Best influence of iodization programmes on the epidemiology of nodular goitre. Best Pract Res Clin Endocrinol Metab. 2014;28(4):577-88. https://pubmed.ncbi.nlm.nih.gov/25047207 https://doi.org/10.1016/j.beem.2014.04.002
Chen W, Sang Z, Tan L, et al. Neonatal thyroid function born to mothers living with long-term excessive iodine intake from drinking water. Clin Endocrinol (Oxf). 2015;83(3):399-404. https://pubmed.ncbi.nlm.nih.gov/25280177 https://doi.org/10.1111/cen.12625
Hisada A, Takatani R, Yamamoto M, et al. Maternal iodine intake and neurodevelopment of offspring: The Japan environment and children's study. Nutrients. 2022;14(9):1826. https://pubmed.ncbi.nlm.nih.gov/35565793 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9105063 https://doi.org/10.3390/nu14091826
Andersson M, Braegger CP. The role of iodine for thyroid function in lactating women and infants. Endocr Rev. 2022;43(3):469-506. https://pubmed.ncbi.nlm.nih.gov/35552681 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9113141 https://doi.org/10.1210/endrev/bnab029
Nishiyama S, Mikeda T, Okada T, Nakamura K, Kotani T, Hishinuma A. Transient hypothyroidism or persistent hyperthyrotropinemia in neonates born to mothers with excessive iodine intake. Thyroid. 2005;14(12):1077-83. https://pubmed.ncbi.nlm.nih.gov/15650362 https://doi.org/10.1089/thy.2004.14.1077
Perrine CG, Cogswell ME, Swanson CA, et al. Comparison of population iodine estimates from 24-hour urine and timed-spot urine samples. Thyroid. 2014;24(4):748-57. https://pubmed.ncbi.nlm.nih.gov/24308769 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993064 https://doi.org/10.1089/thy.2013.0404
World Health Organization. Urinary iodine concentrations for determining iodine status deficiency in populations (VMNIS). http://www.who.int/nutrition/vmnis/ indicators/urinaryiodine
Shelor P, Dasgupta PK. Review of analytical methods for the quantification of iodine in complex matrices. Anal Chim Acta. 2011;702(1):16-36. https://pubmed.ncbi.nlm.nih.gov/21819856 https://doi.org/10.1016/j.aca.2011.05.039
Desai MP, Sharma R, Riaz I, Sudhanshu S, Parikh R, Bhatia V. Newborn screening guidelines for congenital hypothyroidism in India: recommendations of the Indian Society for Pediatric and Adolescent Endocrinology (ISPAE) - Part I: screening and confirmation of diagnosis. Indian J Pediatr. 2018;85(6):440-7. https://pubmed.ncbi.nlm.nih.gov/29380252 https://doi.org/10.1007/s12098-017-2575-y
Lem AJ, de Rijke YB, van Toor H, de Ridder MA, Visser TJ, Hokken-Koelega AC. Serum thyroid hormone levels in healthy children from birth to adulthood and in short children born small for gestational age. J Clin Endocrinol Metab. 2012;97(9):3170-8. https://pubmed.ncbi.nlm.nih.gov/22736771 https://doi.org/10.1210/jc.2012-1759
WHO Multicentre Growth Reference Study Group. WHO child growth standards based on length/height, weight and age. Acta Paediatr Suppl. 2006;450:76-85. https://pubmed.ncbi.nlm.nih.gov/16817681 https://doi.org/10.1111/j.1651-2227.2006.tb02378.x
Phatak P. Developmental assessment scale of Indian infants (DASII), (Revised baroda norms manual, 2997) manual. Anand Agencies, Pune, India; 1997.
Fan X, Zhao L, Wang S, et al. Relation between iodine nutrition and thyroid diseases in Qinghai, China. Front Endocrinol (Lausanne). 2023;14:1234482. https://pubmed.ncbi.nlm.nih.gov/37745704 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10515197 https://doi.org/10.3389/fendo.2023.1234482
Palaniappan S, Shanmughavelu L, Prasad HK, Subramaniam S, Krishnamoorthy N, Lakkappa L. Improving iodine nutritional status and increasing prevalence of autoimmune thyroiditis in children. Indian J Endocrinol Metab. 2017;21(1):85-9. https://pubmed.ncbi.nlm.nih.gov/28217504 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5240087 https://doi.org/10.4103/2230-8210.195996
N øhr SB, Laurberg P. Opposite variations in maternal and neonatal thyroid function induced by iodine supplementation during pregnancy. J Clin Endocrinol Metab. 2015;85(2):623-7. https://pubmed.ncbi.nlm.nih.gov/10690866 https://doi.org/10.1210/jcem.85.2.6391
Osei J, Andersson M, Reijden OV, Dold S, Smuts CM, Baumgartner J. Breast-milk iodine concentrations, iodine status, and thyroid function of breastfed infants aged 2-4 months and their mothers residing in a South African Township. J Clin Res Pediatr Endocrinol. 2016;8(4):381-91. https://pubmed.ncbi.nlm.nih.gov/27217155 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5197995 https://doi.org/10.4274/jcrpe.2720
Kumar D, Raina SK, Chauhan R, Kumar P, Sharma S. Iodine intake among pregnant mothers residing in hilly terrains of two districts of Himachal Pradesh, India. Indian J Public Health. 2021;65(2):185-9. https://pubmed.ncbi.nlm.nih.gov/34135189 https://doi.org/10.4103/ijph.IJPH_1407_20
Bali S, Singh AR, Nayak PK. Iodine deficiency and toxicity among school children in Damoh district, Madhya Pradesh, India. Indian Pediatr. 2018;55(7):579-81. https://pubmed.ncbi.nlm.nih.gov/30129540
Tomoda C, Kitano H, Uruno T, et al. Transcutaneous iodine absorption in adult patients with thyroid cancer disinfected with povidone-iodine at operation. Thyroid. 2005;15(6):600-3. https://pubmed.ncbi.nlm.nih.gov/16029128 https://doi.org/10.1089/thy.2005.15.600
Kapil U, Bhadoria AS. Concerns with urinary iodine excretion level in a single random sample. Indian Pediatr. 2018;55(11):1007. https://pubmed.ncbi.nlm.nih.gov/30587659
Yoon SA, Chang YS, Yang M, et al. Effect of levothyroxine supplementation in extremely low birth weight infants with transient hypothyroxinemia of prematurity. Sci Rep. 2022;12(1):9717. https://pubmed.ncbi.nlm.nih.gov/35690687 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9188355 https://doi.org/10.1038/s41598-022-13927-2
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2024 Deepashree K Rao, Ankur Jindal, Aashima Dabas, Haseena Sait, Sangeeta Yadav, Seema Kapoor
![Creative Commons License](http://i.creativecommons.org/l/by-nc/4.0/88x31.png)
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Journal of the ASEAN Federation of Endocrine Societies is licensed under a Creative Commons Attribution-NonCommercial 4.0 International. (full license at this link: http://creativecommons.org/licenses/by-nc/3.0/legalcode).
To obtain permission to translate/reproduce or download articles or use images FOR COMMERCIAL REUSE/BUSINESS PURPOSES from the Journal of the ASEAN Federation of Endocrine Societies, kindly fill in the Permission Request for Use of Copyrighted Material and return as PDF file to jafes@asia.com or jafes.editor@gmail.com.
A written agreement shall be emailed to the requester should permission be granted.