ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 63 GP176 | DOI: 10.1530/endoabs.63.GP176

Do different initial doses of L-T4 within the range of 10-15 mcg/kg/die influence neurodevelopment during the first two years of life in children with congenital hypothyroidism?

Cristina Moracas1, Gian Paolo Ciccarelli1, Carmela Bravaccio1, Alessandra Cassio2, Roberto Gastaldi3, Alessandro Mussa4, Miriam Polizzi1, Maria Cristina Vigone5, Malgorzata Gabriela Wasniewska6, Giovanna Weber5 & Mariacarolina Salerno1


1Pediatric Endocrine Unit, Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy; 2Pediatric Department, Sant’Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy; 3Department of Pediatrics, Istituto Giannina Gaslini, Genoa, Italy; 4Department of Pediatrics and Public Health, Regina Margherita Children’s Hospital, University of Turin, Turin, Italy; 5Department of Pediatrics, Vita-Salute San Raffaele University, IRCCS San Raffaele Hospital, Milan, Italy; 6Department of Pediatrics, University of Messina, Messina, Italy.


Background: The initial L-T4 dose in the treatment of congenital hypothyroidism (CH) currently recommended is 10–15 mcg/kg/die.

Objective: We designed a multicenter randomized trial to evaluate the effects of different starting dose of L-T4 within the range 10–15 mcg/kg/die on neurocognitive development in children with CH.

Methods: Seventy-two children with CH diagnosed by neonatal screening were enrolled in the study. They were randomly assigned to receive an initial L-T4 dose of 10–12.5 mcg/kg/die (group A) or 12.6–15 mcg/kg/die (group B). All patients underwent clinical examination and FT4 and TSH measurement periodically during the first two years of life. At the age of 12 and 24 months they underwent Griffiths Mental Development Scales to evaluate cognitive development.

Results: Growth during the first two years of life was comparable in the two groups of patients. Neurodevelopmental evaluation showed no significant difference in Global and Subscales Quotients between the two groups – at 12 and at 24 months of age (Table 1).

Table 1
Group AGroup BP
Global Developmental Quotient 12 months105.2±12.6104.5±12.8Ns
Locomotion DQ99.1±14.796.7±18.4Ns
Personal/social DQ97.7±13.7102.2±13.3Ns
Language DQ109.1±10.8107.3±14.6Ns
Eye-hand coordination DQ107.6±17.5104.4±17.8Ns
Performance DQ109.5±19.9109.8±20.6Ns
Global Developmental Quotient 24 months96.9±16.6100.6±16Ns
Locomotion DQ109.1±23.3111.8±22.1Ns
Personal/social DQ93.3±25.399.9±21.4Ns
Language DQ87.7±21.791.2±20.1Ns
Eye-hand coordination DQ100.7±17.5104.4±13.5Ns
Performance DQ102.4±15.4105.4±15Ns

Conclusion: Different initial doses of L-T4 within the range of 10–15 mcg/kg/die are not associated with differences in neurodevelopment during the first two years of life in CH patients.