Evaluation of TSH levels in the program of congenital hypothyroidism newborn screening in a pilot study of preterm newborns in Bogotá, Colombia

Introduction: Preterm infants (<37 weeks of gestation) have low levels of thyroid hormones due to multiple factors. Objective: To evaluate levels of thyroid-stimulation hormone (TSH) in the program congenital hypothyroidism (CH) newborn screening in a sample of preterm infants in the city of Bogotá, Colombia. Methods: The Secretaría de Salud Distrital screening protocol for CH (blood sample is collected from the umbilical cord in all the newborns) remeasured the serum TSH and heel TSH when preterm infants completed 37 weeks of gestation. Results: A total of 59 preterm neonates were rescreened, of which 2 neonates had elevated levels of TSH and 1 neonate had transient hypothyroxinemia. The Kolmogorov-Smirnov 2-sample/bilateral statistical test was used to compare the neonatal TSH levels of preterm and full-term newborns, which do not follow the same distribution. Conclusion: In our pilot study, 2 of the rescreened infants presented high levels of TSH and 1 had transient hyperthyrotropinemia, suggesting the need for rescreening of preterm infants. Additionally, a larger study should be performed to determine the screening cutoff values for preterm newborns.