Newborn of mothers affected by autoimmune thyroiditis: the importance of thyroid function monitoring in the first months of life

Rosanna Rovelli,Arianna Passoni,Giovanna Weber,Ludovica Maina,Maria Cristina Vigone,Fabio Mosca,Giuseppe Chiumello,Andrea Corrias,Carlo Corbetta,Chiara Giovanettoni

doi:10.1186/1824-7288-36-24

Abstract

Backgroundevaluation of thyroid function in neonates born from mothers affected by autoimmune thyroiditis in order to define if a precise follow-up is necessary for these children. The influence of maternal thyroid peroxidase antibody (TPOAb) and L-thyroxine therapy during pregnancy on neonatal thyroid function was also investigated.Methods129 neonates were tested for thyroid function by measurement of free thyroxine (FT4) and thyroid stimulating hormone (TSH) in 3th day, 15th day and at one month of life. TPOAb were measured in all patients; periodical control of thyroid function were performed until 6 months of life if Ab were positive. Data concerning etiology of maternal hypothyroidism and maternal replacement therapy with L-thyroxine during pregnancy were retrospectively collected.Results28% neonates showed at least a mild increase of TSH value at the different determinations. In the majority of them, a spontaneous completely normalisation of TSH value was observed within the first month life. L-thyroxine replacement therapy was started in 3 neonates. TPOAb titer and maternal L-thyroxine replacement therapy were not related to alteration of thyroid hormone function in our study population.Conclusionstransient mild elevation of serum TSH above the normal reference value for age is frequently observed in the first month of life in infants born from mothers affected by autoimmune thyroiditis. Persistent hyperthyrotropinemia requiring replacement therapy is observed in 2.2% of these neonates. According to our experience, follow-up is recommended in these newborns; the most accurate and not invasive way to carefully monitor these infants after neonatal screening for CH seems to be serum-testing TSH between 2ndand 4th week of life.

Highlights

During pregnancy there are many physiological changes of maternal thyroid function
129 neonates (61 females, 68 males) born from mothers affected by autoimmune thyroiditis were enrolled in the present study
One neonate who resulted negative to the neonatal screening for CH and whose thyroid stimulating hormone (TSH) was normal at the first plasma TSH sampling, showed TSH value above the normal reference range in 15th day of life; TSH measurement was repeated and confirmed, so that replacement therapy was started at about one month of life

Summary

Introduction

During pregnancy there are many physiological changes of maternal thyroid function. The lack of maternal thyroid hormone during early pregnancy might have some irreversible effects on fetal development [3]. Dussault et al reported that there is no correlation between the presence of maternal antimicrosomal antibodies and congenital hypothyroidism[12]; a further study conducted in Quebec in 1999 demonstrated an increased prevalence of transient congenital hypothyroidism associated with maternal autoimmune thyroid disease, antimicrosomal autoantibodies were found in 77% of mothers of infants with transient congenital hypothyroidism[13]. The presence of maternal TPOAb with normal maternal thyroid function has been described in association with impaired neuropsychological development during early childhood [14]

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