, Volume 13, Issue 3, pp 375–381 | Cite as

No increase in renal iodine excretion during pregnancy: a telling comparison between pregnant women and their spouses

  • Eftychia KoukkouEmail author
  • Stavros Kravaritis
  • Irene Mamali
  • Georgios G. Markantes
  • Marina Michalaki
  • Georgios G. Adonakis
  • Neoklis A. Georgopoulos
  • Kostas B. Markou
Research paper


OBJECTIVE: Adequate dietary iodine intake is necessary for normal thyroid gland function at all times, and most particularly during pregnancy. Increased iodine loss is cited, among other factors, as responsible for the increased iodine demand in this period. Our aim was to compare renal iodine excretion between women during all three pregnancy trimesters with that of their spouses and thereby to estimate the iodine intake in an a large sample of pregnant women in urban areas in Greece. DESIGN: Four hundred twenty-four healthy pregnant women were included prospectively (residents of Athens n=218, residents of Patras n=206). The spouses of 177 of these women following the same diet were also studied. Determinations included serum FT4, TSH and aTPO and urinary iodine excretion (UIE). RESULTS: No difference was found either in median UIE throughout pregnancy or between the UIE of the pregnant women and their spouses during the trimesters. Throughout pregnancy, mild iodine deficiency was noted and was classified as mild in 60%, moderate in 30% and severe in 10% of the women studied. Users of iodized salt had significantly higher median UIE compared with non-users. Serum FT4 levels decreased and TSH increased as pregnancy progressed. CONCLUSIONS: Our study indicates that renal iodine excretion is not increased during pregnancy. This finding needs to be confirmed by further investigation in other populations with different iodine intakes. Thus, increased iodine requirements in pregnancy are possibly due to extra-renal causes. The population of pregnant women in Greek urban areas is mildly-and often moderately and severely-iodopenic and needs to be treated accordingly.

Key words

Iodine Iodine deficiency Pregnancy Thyroid Urinary iodine excretion 


  1. 1.
    de Escobar GM, Obregón MJ, del Rey FE, 2007 Iodine deficiency and brain development in the first half of pregnancy. Public Health Nutr 10: 1554–1570.CrossRefGoogle Scholar
  2. 2.
    Glinoer D, 2007 The importance of iodine nutrition during pregnancy. Public Health Nutr 10: 1542–1546.CrossRefGoogle Scholar
  3. 3.
    Medeiros-Neto G, Camargo RY, Tomimori EK, 2012 Approach to and treatment of goiters. Med Clin North Am 96: 351–368.CrossRefGoogle Scholar
  4. 4.
    Hynes KL, Otahal P, Hay I, Burgess GR, 2013 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 98: 1954–1962.CrossRefGoogle Scholar
  5. 5.
    Zimmermann MB, Andersson M, 2012 Update on iodine status worldwide. Curr Opin Endocrinol Diabetes Obes 19: 382–387.CrossRefPubMedPubMedCentralGoogle Scholar
  6. 6.
    ICCIDD Global Network. National Iodine Status in 2013. Available at Accesesed August 2013.
  7. 7.
    Zimmermann MB, 2009 Iodine deficiency. Endocr Rev 30: 376–408.CrossRefGoogle Scholar
  8. 8.
    Pearce EN, 2007 National trends in iodine nutrition: is everyone getting enough?. Thyroid 17: 823–827.CrossRefGoogle Scholar
  9. 9.
    Nøhr SB, Laurberg P, Børlum KG, et al, 1993 Iodine deficiency in pregnancy in Denmark: Regional variations and frequency of individual iodine supplementation. Acta Obstet Gynecol Scand 72: 350–353.CrossRefGoogle Scholar
  10. 10.
    Mian C, Vitaliano P, Pozza D, et al, 2009 Iodine status in pregnancy: role of dietary habits and geographical origin. Clin Endocrinol (Oxf) 70: 776–780.CrossRefGoogle Scholar
  11. 11.
    Marchioni E, Fumarola A, Calvanese A, et al, 2008 Iodine deficiency in pregnant women residing in an area with adequate iodine intake. Nutrition 24: 458–461.CrossRefGoogle Scholar
  12. 12.
    Kibirige MS, Hutchison S, Owen CJ, Delves HT, 2004 Prevalence of maternal dietary iodine insufficiency in the north east of England: implications for the fetus. Arch Dis Child Fetal Neonatal Ed 89: F436–439.CrossRefPubMedPubMedCentralGoogle Scholar
  13. 13.
    Koutras DA, Alexander WD 1964 Excretion of iodine. In: Koutras DA, Alexander WD (eds) Clinical Aspects of Iodine Metabolism, Blackwell Scientific Publications, Oxford, England; pp, 73–82.Google Scholar
  14. 14.
    Glinoer D, 2001 Pregnancy and Iodine. Thyroid 11: 471–481.CrossRefGoogle Scholar
  15. 15.
    Doufas AG, Mastorakos G, Chatziioannou S, et al, 1999 The predominant form of non-toxic goiter in Greece is now autoimmune thyroiditis. Eur J Endocrinol 140: 505–511.CrossRefGoogle Scholar
  16. 16.
    Michalaki M, Kyriazopoulou V, Paraskevopoulou P, Vagenakis AG, Markou KB, 2008 The odyssey of nontoxic nodular goiter (NTNG) in Greece under suppression therapy, and after improvement of iodine deficiency. Thyroid 18: 641–645.CrossRefGoogle Scholar
  17. 17.
    Tsatsoulis A, Johnson EO, Andricula M, et al, 1999 Thyroid autoimmunity is associated with higher urinary iodine concentrations in an iodine-deficient area of Northwestern Greece. Thyroid 9: 279–283.CrossRefGoogle Scholar
  18. 18.
    Kaloumenou I, Alevizaki M, Ladopoulos C, et al, 2007 Thyroid volume and echostructure in schoolchildren living in an iodine-replete area: relation to age, pubertal stage, and body mass index. Thyroid 17: 875–881.CrossRefGoogle Scholar
  19. 19.
    Pearce EN, Alexiou M, Koukkou E, et al, 2012 Perchlorate and thiocyanate exposure and thyroid function in first-trimester pregnant women from Greece. Clin Endocrinol (Oxf) 77: 471–474.CrossRefGoogle Scholar
  20. 20.
    Dunn JT, Crutchfield HE, Gutekunst R, Dunn AD, 1993 Two simple methods for measuring iodine in urine. Thyroid 3: 119–123.CrossRefGoogle Scholar
  21. 21.
    Smyth PP, 1999 Variation in iodine handling during normal pregnancy. Thyroid 9: 637–642.CrossRefGoogle Scholar
  22. 22.
    Stilwell G, Reynolds P, Parameswaran V, Blizzard L, Greenaway TM, Burgess JR, 2008 The Influence of Gestational Stage on Urinary Iodine Excretion in Pregnancy. J Clin Endocrinol Metab 93: 1737–1742.CrossRefGoogle Scholar
  23. 23.
    Gültepe M, Ozcan O, Ipçioglu OM, 2005 Assessment of iodine intake in mildly iodine-deficient pregnant women by a new automated kinetic urinary iodine determination method. Clin Chem Lab Med 43: 280–284.CrossRefGoogle Scholar
  24. 24.
    Brander L, Als C, Buess H, et al, 2003 Urinary iodine concentration during pregnancy in an area of unstable dietary iodine intake in Switzerland. J Endocrinol Invest 26: 389–396.CrossRefGoogle Scholar
  25. 25.
    Koutras DA, 2000 Circulating iodide concentrations during and after pregnancy. J Clin Endocrinol Metab 85: 1345.CrossRefGoogle Scholar
  26. 26.
    Smyth PP, Smith DF, Sheehan S, Higgins M, Burns R, O’Herlihy C, 2007 Short-term changes in maternal and neonatal urinary iodine excretion. Thyroid 17: 219–222.CrossRefGoogle Scholar
  27. 27.
    Burns R, Azizi F, Hedayati M, Mirmiran P, O’Herlihy C, Smyth PP, 2011 Is placental iodine content related to dietary iodine intake? Clin Endocrinol (Oxf) 75: 261–264.CrossRefGoogle Scholar
  28. 28.
    Dworkin HJ, Jacquez JA, Beierwaltes WH, 1966 Relationship of iodine ingestion to iodine excretion in pregnancy. J Clin Endocrinol 26: 1329–1336.CrossRefGoogle Scholar
  29. 29.
    Pierce JG, Faith MR, Giudice LC, Reeve JR, 1976. Structure and structure-function relationships in glycoprotein hormones. Ciba Found Symp 41: 225–250.PubMedGoogle Scholar
  30. 30.
    Smyth PP, Wijeyaratne CN, Kaluarachi WN, et al, 2005 Sequential studies on thyroid antibodies during pregnancy. Thyroid 15: 474–477.CrossRefGoogle Scholar
  31. 31.
    Markou KB, Koukkou EG, 2012 The Greek population is iodine sufficient and not at risk of iodine-induced hyperthyroidism. J Nutr 142: 1611; author reply 1612.CrossRefGoogle Scholar
  32. 32.
    Caldwell KL, Miller GA, Wang RY, Jain RB, Jones RL, 2008 Iodine status of the U.S. population, National Health and Nutrition Examination Survey 2003–2004. Thyroid 18: 1207–1214.CrossRefGoogle Scholar
  33. 33.
    Caron P, Hoff M, Bazzi S, et al, 1997 Urinary iodine excretion during normal pregnancy in healthy women living in the southwest of France: correlation with maternal thyroid parameters. Thyroid 7: 749–754.CrossRefGoogle Scholar
  34. 34.
    Hollowell JG, Staehling NW, Hannon WH, et al, 1998 Iodine nutrition in the United States. Trends and public health implications: iodine excretion data from National Health and Nutrition Examination Surveys I and III (1971–1974 and 1988–1994). J Clin Endocrinol Metab 83: 3401–3408.PubMedGoogle Scholar
  35. 35.
    Gowachirapant S, Winichagoon P, Wyss L, et al, 2009 Urinary iodine concentrations indicate iodine deficiency in pregnant Thai women but iodinesufficiency in their school-aged children. J Nutr 139: 1169–1172.CrossRefGoogle Scholar
  36. 36.
    Hollowell JG, Haddow J, 2007 The prevalence of iodine deficiency in women of reproductive age in the United States of America. Public Health Nutr 10: 1532–1539.CrossRefGoogle Scholar
  37. 37.
    Pearce EN, 2008 Iodine in pregnancy: is salt iodization enough? J Clin Endocrinol Metab 93: 2466–2468.CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Hellenic Endocrine Society 2014

Authors and Affiliations

  • Eftychia Koukkou
    • 1
    Email author
  • Stavros Kravaritis
    • 2
  • Irene Mamali
    • 3
  • Georgios G. Markantes
    • 2
  • Marina Michalaki
    • 3
  • Georgios G. Adonakis
    • 2
  • Neoklis A. Georgopoulos
    • 2
    • 3
  • Kostas B. Markou
    • 3
  1. 1.Department of Endocrinology, Diabetes and Metabolism“Elena Venizelou” HospitalAthensGreece
  2. 2.Department of Obstetrics and GynecologyUniversity of PatrasPatrasGreece
  3. 3.Department of EndocrinologyUniversity of PatrasPatrasGreece

Personalised recommendations