RESUMO
INTRODUCTION: Thyroid dysfunction is a common problem in pregnant women. It is usually of an autoimmune origin, with Hashimotós thyroiditis and Graves disease being the most common conditions. Although hormonal changes and transplacental antibody transfer may occur, specific neonatal screening has not been shown to be useful. PATIENTS AND METHOD: A prospective study of newborns of women with autoimmune thyroid disease born at a level III university hospital (November 2013-December 2016). Neonates were selected during their stay at the maternity. Babies with perinatal asphyxia were excluded. Data were collected from the clinical histories of mothers and newborns. RESULTS: A total of 191 neonates were included. Ninety percent of mothers had been diagnosed with autoimmune hypothyroidism. Only 5.8% of newborns had some laboratory disorder, consisting of slightly increased thyroid-stimulating hormone levels, which returned to normal at the age of one month and did not correlate to thyroid peroxidase antibody levels. Transient hyperthyrotropinemia was diagnosed in one newborn and required thyroxin treatment during the first year of life. Among newborns from mothers with Graves disease, 36.8% had some abnormal laboratory value during the first 7 days of life, but there were no cases of hyperthyroidism and only one of transient hyperthyrotropinemia. CONCLUSIONS: Experience at our hospital in screening of newborns from hypothyroid mothers reveals a high number of laboratory controls with a poor diagnostic yield. No relationship was found between thyroid peroxidase antibody levels and thyroid dysfunction. We support the recommendations to continue testing serum thyroid-stimulating hormone and FT4 levels at 48h of life in newborns of mothers with autoimmune hypothyroidism.
