Nutritional Sciences

The Korean Nutrition Society (한국영양학회)
권호 표지

Study of Thyroid-Related Hormones During Second Trimester of Pregnancy

  • Laeeq Faiqa (Institute of Chemistry, University of the Punjab) ;
  • Nagra Saeed Ahmad (Institute of Chemistry, University of the Punjab) ;
  • Elahi Shan (Centre for Nuclear Medicine, Mayo Hospital)
  • Published : 2005.08.01
Download PDF
⟨ Previous Next ⟩

Abstract

A study during second trimester of pregnancy was conducted among 100 women from a population with mild to moderate deficient iodine intake (median 7 ${\mu}g$/L)to monitor the changes in serum free thyroxin ($FT_4$), triiodothyionine ($T_3$) and thyrtropin (TSH). Thyroid related hormones were assessed using radioimmunoassay (RIA) and immunoradiometricassay (IRMA). As compared with non pregnant women, mean $FT_4$ levels decreased, $T_3$ levels increased and TSH levels were slightly depressed in pregnant women. Mean $FT_4$ concentration reached its highest level in the $4^{th}$ month and linearly decreased until the $6^{th}$ month. Mean $T_3$ level remained almost constant during $2^{nd}$ trimester of pregnancy. Mean TSH level remained unaltered during the $4^{th}$ and $5^{th}$ months and was slightly lower than that for the control group. However, these differences were statistically insignificant At the end of the second trimester, hypothyroxinemia and $T_3$ levels greater than the upper limit of the laboratory reference range were found in $34\%$ and $38\%$ of women, respectively. These changes in thyroid hormones reflect typical adaptations of the thyroid gland during pregnancy to the limited availability of iodine.

Keywords

References

  1. Glinoer D. What happens to the normal thyroid during pregnancy? Thyroid 9:631-635, 1999 https://doi.org/10.1089/thy.1999.9.631
  2. Glinoer D. The regulation of thyroid function in pregnancy: pathways of endocrine adaptation from physiology. Endocr Rev 18:404-33, 1997 https://doi.org/10.1210/er.18.3.404
  3. Mezosi E, Molnar I, Jakab A, Balogh E, Karanyi Z, Pakozdy Z, Nagy P, Gyory F, Szabo J, Bajnok L, Leovey A, Kakuk G, Nagy A. Prevalence of iodine deficiency and goiter during pregnancy in east Hungry. E.V. Eur J Endocrinol 143:479-83, 2000 https://doi.org/10.1530/eje.0.1430479
  4. Caron P, Hoff M, Bassi S, Dufor A, Faure G, Ghandour I, Lausu P, Lucas Y, Maraval D, Mignot F, Ressigeac P, Vertongen F, Grange V. Urinary iodine excretion during normal pregnancy in healthy women living in the Southwest of France: correlation with maternal thyroid parameter. Thyroid 7:749-754, 1997 https://doi.org/10.1089/thy.1997.7.749
  5. Vermiglio F, Lo-Presti VP, Castagna MG, Visli MA, Moleti M, Finocchiaro MD, Mattina F, Artemisia A, Trimarchi F. Increased maternal thyroid failure with pregnancy progression in an iodine deficient area with major iodine deficiency disorders. Thyroid 9:19-24, 1999 https://doi.org/10.1089/thy.1999.9.19
  6. Bernal J, Guadano-Ferraz A, Morte B. Perspectives in the study of thyroid hormone action on brain development and function. Thyroid 13:1005-1012, 2003 https://doi.org/10.1089/105072503770867174
  7. Auso E, Lavado-Autric R, Cuevas E, Escobar del Rey F, Morreale de Escobar G, Berbel P. A moderate and transient deficiency of maternal thyroid function at the beginning of fetal neocorticogenesis alters neuronal migration. Endocrinology 145:4037-4047, 2004 https://doi.org/10.1210/en.2004-0274
  8. UNICEF. Iodine Deficiency Disorders (IDD). Medical Herald (special supplement) 18:11-14, 2001
  9. Akhter P, ur-Rehman K, Orfi SD, Ahmad N. Assessment of iodine levels in the Pakistani diet. Nutrition 20:783-787, 2004 https://doi.org/10.1016/j.nut.2004.05.019
  10. Goverment of Pakistan. National Nutrition Survey 2001-2002. Planning Commission. Islamabad, 2003
  11. Government of Pakistan. Life cycle approach to women's health. In: Pakistan reproductive health service package. pp.5, Ministry of health and population welfare. Islamabad, 1999
  12. Government of Pakistan. National Nutrition Survey Report. National Institute of Health, Islamabad, 1998
  13. Elahi S, Syed Z, Nagra SA. Status of iodine deficiency disorders as estimated by neonatal cord serum thyrotrophin in Lahore, Pakistan. Nutr Res 24:1005-10, 2004 https://doi.org/10.1016/j.nutres.2004.07.004
  14. Fareeha R. Iodine intake and thyroid related hormones during first trimester of pregnancy. M. Sc. Thesis. Institute of Chemistry, University of the Punjab, Lahore. 2002
  15. Abbas HG, Elahi S, Khan MS, Naeem M. Serum thyroxine $(T_{4})$ and thyroid stimulating hormone (TSH) levels in cord blood of newborns in Lahore. Pak J Med Sci 19:211-216, 2003
  16. Sneedecor GW, Cochran WG. Statistical Methods. Iowa State University Press, 1976
  17. Glinoer D, DeNayer P, Bourdoux P, Lemone M, Robyn C, Van Steirteghem A. Regulation of maternal thyroid during pregnancy. J Clin Endocrinol Metab 71:276-287, 1990 https://doi.org/10.1210/jcem-71-2-276
  18. Yoshimura M, Hershman JM. Thyrotrophic action of human chorionic gonadotropin. Thyroid 5:425-434, 1995 https://doi.org/10.1089/thy.1995.5.425
  19. Pop VJ, Kuipens J, Van L, Barr AL. Low normal maternal free $T_{4}$ concentrations during early pregnancy are associated with impaired psychomotor development in infancy. Clin Endocrinol 50:149-155, 1999 https://doi.org/10.1046/j.1365-2265.1999.00639.x
  20. Calvo RM, Jauniaux E, Gulbis B, Asuncion M, Gervy C, Contempre B, Morreale de Escobar G. Fetal tissues are exposed to biologically relevant free thyroxine concentrations during early phases of development. Possible consequences of maternal hypothyroxinemia. J Clin Endocrinol Metab 87:1768-1777, 2002 https://doi.org/10.1210/jc.87.4.1768
  21. Dillon JC, Milliez J. Reproductive failure in women living in iodine deficient areas of West Africa. Br J Obstet Gynocol 107:631-636, 2000 https://doi.org/10.1111/j.1471-0528.2000.tb13305.x
  22. Glinoer D. The systematic screening and management of hypothyroidism and hyperthyroidism during pregnancy. Trends Endocrinol Metab 10:403-411, 1998
  23. Dunn JT, Delange F. Damaged reproduction: The most important consequence of iodine deficiency. J Clin Endocrinol Metab 86:2360-2363, 2001 https://doi.org/10.1210/jc.86.6.2360
  24. UNICEF. Punjab: socio-economic profile. In: A better future for children and women in Pakistan, pp.1-13, Lahore, 1995