Does Hypothyroxinemia of Preterm Neonates Persist Beyond 7 weeks of Life?

  • Jhulan Das SharmaEmail author
  • M. F. H. Nazir
  • Abdul Gofur Khan
  • Baharul Hoque
Original Article



To determine whether hypothyroxinemia in the early neonatal period normalizes by 7 wk of postnatal age.


An observational study was carried out from July 2008 through June 2010 in the neonatal and postnatal unit of Chittagong Medical College Hospital, Bangladesh. A total of 150 neonates including 100 preterm and 50 term neonates were selected by convenient sampling. Preterm neonates were stratified according to postconceptional age. By the 3rd generation two site chemiluminesent immunometric assay, free T4 (FT4) and thyroid stimulating hormone (TSH) estimations were done. Within 5–11 d, first samples were collected from all the neonates and the second samples of hypothroxinemic preterm neonates were collected within 42–50 d of birth.


Positive correlation of FT4 was found with gestational age (p < 0.0001, n = 100, r = 0.61) in preterm neonates while significant difference was found among the gestational age subgroups (p = 0.0001). No significant differences were, however, found in TSH levels of such age groups of the preterms. Highly significant differences in FT4 and TSH levels between 1st and 2nd samples were found in subgroup analysis of the preterm neonates. In the 1st samples, TSH level correlated positively with gestational age but in the 2nd samples, significant negative correlation was observed. In all neonates with initial hypothyroxinemia, FT4 levels were found to increase to reach the normal levels by 7 wk.


FT4 level normalizes by 7 wk of birth in preterm newborn neonates.


Preterm neonates FT4 TSH Bangladesh 



The authors acknowledge Dr. Shimita Shome. the then MD (Thesis part) student for helping in sample and report collection and Dr. Jagadish Chandra Das, Professor of Neonatology, for constructive criticism and overall supervision of data collection procedure.

Authors’ Contributions

JDS: Conceptualized and designed the study, designed research instrument, participated in data collection. He drafted the initial manuscript and approved the final manuscript as submitted; MFHN, AGK and BH: Conceptualized the study; reviewed and revised the manuscript, and approved the final manuscript as submitted. He also guided and supervised the study. JDS will act as guarantor for this article.

Compliance with Ethical Standards

Conflict of Interest



  1. 1.
    Rabin CW, Hopper AO, Job L, et al. Incidence of low freeT4 values in premature neonates as determined by direct equilibrium dialysis. J Perinatol. 2004;24:640–4.CrossRefGoogle Scholar
  2. 2.
    Forghani N, Aye T. Hypothyroxinemia and prematurity. NeoRev. 2008;9:e66–71.CrossRefGoogle Scholar
  3. 3.
    Chung HR, Shin CH, Yang SW, et al. High incidence of thyroid dysfunction in preterm neonates. J Korean Med Sci. 2009;24:627–31.CrossRefGoogle Scholar
  4. 4.
    Williams FL, Mires GJ, Barnett C, et al. Transient hypothyroxinaemia in preterm neonates: the role of cord sera thyroid hormone levels adjusted for prenatal and intrapartum factors. J Clin Endocrinol Metab. 2005;90:4599–606.CrossRefGoogle Scholar
  5. 5.
    Fisher DA. Foetal Thyroid Function: Diagnosis and Management of Foetal Thyroid Disorders. California: Lippincott-Raven Publishers; 1997. p. 16–31.Google Scholar
  6. 6.
    LaFranchi S. Thyroid function in the preterm neonates. Thyroid. 1999;9:71–8.CrossRefGoogle Scholar
  7. 7.
    van Wassenaer AG, Kok JH. Hypothyroxinaemia and thyroid function after preterm birth. Semin Neonatol. 2004;9:3–11.CrossRefGoogle Scholar
  8. 8.
    Brown RS, LaFranchi S, Rose SR. Congenital hypothyroidism. J Clin Endocrinol Metab. 2009;94:E2.Google Scholar
  9. 9.
    Nahar J, Zabeen B, Akhter S, Azad K, Nahar N. Neonatal morbidity and mortality pattern in special care baby unit of BIRDEM. Ibrahim Med Coll J. 2007;1:1–4.CrossRefGoogle Scholar
  10. 10.
    Sharma JD, Afroze S, Salam MA, et al. Comparative study of thyroid function test between preterm and term neonates. Bangladesh J Child Health. 2003;27:33–7.Google Scholar
  11. 11.
    LaFranchi S. Thyroid development and physiology. In: Kliegman RM, Behrman R, Jenson H, Stanton BF, editors. Nelson Textbook of Pediatrics. 18th ed. Philadelphia: Saunders-Elsevier; 2007. p. 2316–7.Google Scholar
  12. 12.
    Bernal J. Thyroid hormones in brain development and function. Vitam Horm. 2005;71:95–122.CrossRefGoogle Scholar
  13. 13.
    Reuss ML, Paneth N, Pinto-Martin JA, Lorenz JM, Susser M. Hypothyroxinaemia in preterm neonates and neurological development at two years age. N Engl J Med. 1996;334:821–7.CrossRefGoogle Scholar
  14. 14.
    Den Ouden AL, Kok JH, Verkerk PH, Brand R, Verloove-Vanhorick SP. The relation between neonatal thyroxine levels and neurodevelopmental outcome at age 5 and 9 years in a national cohort of very preterm and/or very low birth weight neonates. Pediatr Res. 1996;39:142–5.CrossRefGoogle Scholar
  15. 15.
    Cartault Grandmottet A, Cristini C, Tricoire J, Rolland M, Tauber MT, Salles JP. TSH, FT4 and T3T evaluation in normal and preterm hospitalized newborns. Arch Pédiatr. Article in French. 2007;14:138–43.CrossRefGoogle Scholar
  16. 16.
    Dembinski J, Arpe V, Kroll M. Thyroid function in healthy and sick very-low-birth-weight neonates- TSH and free thyroxine levels until the sixth week of age. Biol Neonate. 2001;80:210–4.CrossRefGoogle Scholar
  17. 17.
    Clemente M, Ruiz-Cuevas P, Carrascosa A, et al. Thyroid function in preterm neonates 27-29 weeks of gestational age during the first four months of life: results from a prospective study comprising 80 preterm neonates. J Pediatr Endocrinol Metab. 2007;20:1269–80.CrossRefGoogle Scholar
  18. 18.
    Adams LM, Emery JR, Clark SJ, Carlton EI, Nelson JC. Reference ranges for newer thyroid function tests in premature neonates. J Pediatr. 1995;126:122–7.CrossRefGoogle Scholar
  19. 19.
    Hirano T, Singh J, Srinivasan G, Pildes R. Postnatal thyroid function in low birth weight neonates: a cross–sectional assessment of free thyroxine and thyroid hormone binding globulin. Eur J Pediatr. 1982;139:244–6.CrossRefGoogle Scholar
  20. 20.
    Torkaman M, Ghasemi F, Amirsalan S, et al. Thyroid function test in pre-term neonates during the first five weeks of life. Int J Prev Med. 2013;4:1271–6.Google Scholar
  21. 21.
    Delange F, Dalhem A, Bourdoux P, et al. Increased risk of primary hypothyroidism in preterm neonates. J Pediatr. 1984;105:462–9.CrossRefGoogle Scholar
  22. 22.
    Frank JE, Faix JE, Hermos RJ, et al. Thyroid function in very low birth weight neonates: effects on neonatal hypothyroidism screening. J Pediatr. 1996;128:548–54.CrossRefGoogle Scholar
  23. 23.
    van Wassenaer AG, Kok JH, Dekker FW, de Vijlder JJ. Thyroid function in very preterm neonates: influences of gestational age and disease. Pediatr Res. 1997;42:604–9.CrossRefGoogle Scholar
  24. 24.
    Mercado M, Yu VYH, Francis I, Szymonowicz W, Gold H. Thyroid function in very preterm neonates. Early Hum Dev. 1988;16:131–41.CrossRefGoogle Scholar

Copyright information

© Dr. K C Chaudhuri Foundation 2019

Authors and Affiliations

  • Jhulan Das Sharma
    • 1
    Email author
  • M. F. H. Nazir
    • 2
  • Abdul Gofur Khan
    • 3
  • Baharul Hoque
    • 3
  1. 1.Department of PediatricsSouthern Medical College & HospitalChittagongBangladesh
  2. 2.Department of PediatricsDoctor MR Khan Shishu HospitalDhakaBangladesh
  3. 3.Department of ZoologyChittagong UniversityChittagongBangladesh

Personalised recommendations