Recovery Rate of Hyperthyrotropinemia and Its Associated Factors: A Prospective Observational Study

Hyperthyrotropinemia (HT) can be transient or permanent. There is no specific protocol in confirmatory tests to discriminate between transient and permanent forms. The aim of this study was to investigate the prevalence of transient HT and the factors that help to discriminate transient from permanent HT.

This was an observational prospective study in all neonates diagnosed with HT referred to the pediatric clinic of Boali Hospital, affiliated to Islamic Azad University Tehran Faculty of Medicine, Tehran, Iran during September 2017 and January 2019. The recovery rate was investigated during a three-month follow-up while withholding medical treatment. Data were analyzed with SPSS Version 22.0.

Totally, 80 neonates (65% girls) were enrolled in this study. Among them, 62 participants (77.5%) recovered without any treatment during the three months of follow-up. The recovery rate was significantly higher in term newborns (p < 0.01). The mean weight of recovered neonates (2767.7 ± 440.2 gr) was significantly higher than that of the neonates who did not recover (2141.7 ± 755.2) (p < 0.01). The mean level of thyroid-stimulating hormone (TSH) of the recovered neonates (9.4 ± 3.0 mIU/L) was significantly lower than in the neonates who did not recover (22 ± 6.5 mIU/L) (p < 0.01).

The outcome of HT became mostly permanent in patients with a higher level of TSH. The prematurity and low birth weight were the influential factors on TSH level, which could indirectly increase the risk of HT permanence.