Hypothyroxinemia in Preterm Neonates: Not Always Hypothyroidism

Bhatia, Vijayalakshmi

doi:10.1007/s12098-019-03015-1

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…[17] An Indian study also had observed that hypothyroxinemia of prematurity is transient and spontaneous recovery occurs by 6-8 weeks of age, which supports observations made in the present study. [18] The current study also observed that preterm neonates mature and stabilize to have normal thyroid function by 2-4 weeks of age. Hence, this study recommends that the estimation of serum thyroid function tests can be postponed to 2 weeks of life, instead on day 3 after birth.…”

Section: Discussionsupporting

confidence: 73%

A study on normalization of hypothyroxinemia in neonates below 34 weeks of gestation

Gaonkar

Shenoi

Sathyanarayana³

et al. 2022

JPED

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Objectives: The aim of the study was to estimate the time required for normalization of hypothyroxinemia of prematurity in neonates below 34 weeks of gestation. Material and Methods: A retrospective study was conducted in neonates born below 34 weeks of gestation, between January 2015 and December 2016. Data were collected on free thyroxine (fT4) and thyroid-stimulating hormone (TSH) levels, tested on days 3, 14, 28, and 42. Gestational age, birth weight, use of antenatal steroids, mechanical ventilation, and various preterm morbidities, along with development at 18 months of corrected age, were comparatively analyzed in neonates with and without hypothyroxinemia. The median time for normalization of fT4 in all these variables was estimated. Results: On day 3, low fT4 was noted in 69 (37.7%) out of 183 neonates born below 34 weeks of gestation; all had normal TSH levels. Hypothyroxinemia showed statistically significant association with gestational age, birth weight, antenatal steroid use, respiratory distress syndrome, invasive ventilation, shock, sepsis, patent ductus arteriosus (PDA), anemia during stay in neonatal intensive care unit, and development at 18 months. Median time for normalization was 14 days in most of the neonates, and 28 days in those with <28 weeks of gestational age, weight of <1000 g and with shock, anemia, and PDA. Two infants with hypothyroxinemia received therapy with levothyroxine at 6 weeks for a short duration, as TSH was high. Conclusion: Hypothyroxinemia of prematurity takes 14–28 days to normalize based on maturity, weight, and illnesses. This study recommends serum fT4 testing at 2 weeks of life, provided congenital hypothyroidism was ruled out by 3–4 days of life, using direct blood spot card metabolic screening.

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Section: Discussionsupporting

confidence: 73%

A study on normalization of hypothyroxinemia in neonates below 34 weeks of gestation

Gaonkar

Shenoi

Sathyanarayana³

et al. 2022

JPED

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“…The reason for these additional measurements relies on the expected lag in the postnatal TSH rise (absence or delay of TSH surge) and on potential hypothyroxinemia, due to hypothalamic-pituitary-thyroid axis immaturity. Both are strongly in uenced by the gestational age: the lower the gestational age, the lower and delayed the TSH, TT4 and FT4 peaks [18,20,[21][22][23][24][25][26][27]. Several studies have reported that screening solely based on an increase of TSH levels likely results in a failure to detect CH in most preterm/VLBW babies.…”

Section: Discussionmentioning

confidence: 99%

“…Many situations in the neonatal period, besides prematurity and VLBW, may affect thyroid function, thus interfering with the diagnosis of CH. Given that any impairment of thyroid status (either isolated hypothyroxinemia or hypothyroidism) may cause neurodevelopmental disorders, screening should be repeated, and children must be carefully followed up until normalization of thyroid function or evolution to permanent HC [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Neonatal Screening Program of Congenital Hypothyroidism: How Can We (Still) Improve?

Costeira

Martins

Reis

et al. 2021

Preprint

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Background: Congenital hypothyroidism (CH) has severe and irreversible neurological consequences for the child if treatment is not readily initiated, which justifies fast diagnosis. Screening of CH is a universal procedure well established in Portugal. It is based on measuring the pituitary thyroid stimulating hormone. The physiology of maturation of the pituitary-thyroid axis is incomplete at delivery in preterm and very-low birth weight babies (VLBW), which raises concerns with respect to the standard timing of CH diagnosis.The Portuguese Neonatal Screening Program recommends testing preterm/VLBW babies at three time points. The purpose of this study was to assess compliance of these guidelines.Methods: Questionnaires were sent to neonatal care units (NCU) and to general practitioner community health units in two time periods.Results: All NCU have written guidelines and the great majority follows the recommendations. Few NCU still postpone the first collection for newborns with protein intake restrictions, some retest new-borns in special circumstances, and a great number still use iodine disinfectants.Conclusions: This study shows that performing the metabolic screening is a well standardized procedure that can still be improved: not delaying the first collection, retesting sick and medicated babies, and avoiding iodine disinfectants.

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“…In a resource limited setting like India, it is difficult to do repeated thyroid testing in babies and the priority remains to implement universal newborn screening so as not to miss congenital hypothyroidism. [8] Decisions regarding levothyroxine treatment should be individualized and taken after considering all the factors. [9]…”

Section: Journal Of Pediatric Endocrinology and Diabetesmentioning

confidence: 99%