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Dokter Emese BOROS

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Project

Newborn screening for congenital hypothyroidism in term and preterm newborns in Federation Wallonie Bruxelles: critical appraisal of real-life results.

Project supervisor

Labo of hospitaal waar het project plaatsvindt

Laboratory or Hospital where the main work will be performed : Hôpital
Universitaire de Bruxelles, HUDERF,ULB and Laboratory of Paediatric
Research, ULB

Objectives of research

Our main objective is to validate, in term newborns, the screening as soon as 48 h of life, by comparing TSH on DBS collected <72 h of life with those collected ≥72 h of life. Our secondary aim is to compare home vs hospital DBS collection in terms of screening performance. For preterm newborns our objective is to evaluate the necessity of repeating DBS in all preterm newborns, by noting the timing of DBS in positive cases and by analyzing the dynamic of TSH during the first month of life. A secondary objective is to analyze the distribution of TSH in function of gestational age and birth weight in order to see if different gestational age dependent cut-off values would be necessary.

Summary

Primary congenital hypothyroidism is a condition characterized by insufficient production of thyroid hormones, usually due to abnormal thyroid development or to thyroid dyshormonogenesis. Its serious consequences on the growth and intellectual development of the child, in the absence of early care, are well documented in the literature. The clinical diagnosis in the first days of life is difficult, while its early treatment with L-Thyroxine radically transforms its prognosis in terms of intellectual development, growth and quality of life of children. These two elements fully justify routine newborn screening. Newborn screening based on measuring TSH on dry blood spot samples, developed in Europe in the 1970s, led to early diagnosis and management. In Belgium, newborn screening for congenital hypothyroidism on the 5th day of life was implemented in 1976. Over the years, the age at screening has changed from 5 to 3 days of life. However, the 2015 reform of the "childbirth with shortened hospital stay" project led to a reorganization of screening, and since November 2019 screening takes place as early as 48 hours of life, before discharge. It is important to ensure that this early collection does not increase the number of false positive cases. The objective of this study is to validate early neonatal screening, in term newborns, as early as 48 hours of life, by comparing the TSH results of newborns who have been screened before 72 hours, to those who have been screened after 72 hours. It is also proposed to compare the results of the screening that took place at home with those that took place in the maternity ward. Due to immaturity of the hypothalamic-pituitary axis in preterm infants, interpretation of TSH results is difficult. There is no consensus on what to do in terms of screening for congenital hypothyroidism in premature newborns. Some centers repeat screening systematically at 14 days and one month, other suggest the use of threshold values specific to preterm newborns and still other carry out a single sample using the same threshold values as for term newborns. Premature babies screened by the ULB screening center, have screening on day 3, day 14 and at discharge or day 30 for those who are still hospitalized. The objective of this study is to study TSH levels in premature infants during the first month of life. It is proposed to analyze the distribution of TSH according to gestational age and birth weight, to see if different cut[1]off values would be necessary according to gestational age, in order to improve the quality of the screening.