Screening and management of thyroid dysfunction in preterm infants

Abstract

Preterm infants can suffer various thyroid dysfunctions associated with developmental immaturity of the hypothalamic-pituitary-thyroid axis, postnatal illness, medications, or iodine supply. The incidence of thyroid dysfunction among preterm infants is higher than that among term infants and has been increasing with improvement in the survival of preterm infants. Hypothyroxinemia is frequently observed during the first week of life in extreme preterm neonates, and the incidence of delayed thyrotropin elevation is high at the age of 2–6 weeks. Although the necessity of routine rescreening remains controversial, recent guidelines on screening for congenital hypothyroidism have recommended rescreening of all preterm neonates. Thyroid hormone replacement is recommended for persistent thyrotropin elevation with or without hypothyroxinemia. Hypothyroxinemia without thyrotropin elevation does not require treatment, and some potential risks of levothyroxine supplementation have been reported. Although most thyroid dysfunctions are transient, careful follow-up after discontinuation of levothyroxine is considered so as to avoid missing persistent hypothyroidism.

Factors associated with permanent hypothyroidism in infants with congenital hypothyroidism

“…In our study, there was no difference in the proportion of TCH patients between the term and preterm groups. It is known that delayed TSH elevation is common in preterm infants, and these patients generally have transient CH [20]. In our study, 31.4% of preterm babies showed delayed TSH elevation, and only one of preterms with delayed TSH elevation failed to discontinue levothyroxine.…”

Bone Mineral Density, Body Composition, and Metabolic Health of Very Low Birth Weight Infants Fed in Hospital Following Current Macronutrient Recommendations during the First 3 Years of Life

“…The major strengths of the present study are the meticulous longitudinal assessment of children’s growth during infancy and the use of DXA to measure total and regional body composition. Thyroid dysfunction is increased in preterm infants and has been shown to impact outcome [ 63 ]. In our infants the assessment of the thyroid status was part of the clinical routine.…”

Thyroid Function of Preterm Twins Having Breastmilk from Their Mothers Consuming Seaweed Soup Might Be Variable between Siblings: A Case Series

“…In infant A-1, fT4 level was decreased to 0.53 ng/dL (normal, www.e-kjp.org Perinatology cations such as dopamine, glucocorticoid, furosemide, and phenobarbital are known to affect thyroid function. 15 Furthermore, iodine in topical antiseptic agents and contrast media can affect thyroid function of preterm neonates. 16 In our NICU, iodine antiseptic agent has not been used for many years, so any effect of topical iodine antiseptic agents could be ruled out.…”

“…It is known that the size of the thyroid gland affects thyroid hormone synthesis and storage capacity. 15 We performed thyroid ultrasonography, and all patients' thyroid glands were normal in size and location.…”