ESPE2019 Poster Category 1 Late Breaking Posters (28 abstracts)
1Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea, Republic of. 2Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Korea, Republic of. 3Department of Pediatrics, Seoul National University Bundang Hospital, Seoul, Korea, Republic of
Objective: We evaluated frequency and risk factors of delayed TSH elevation (dTSH) and investigated follow-up outcomes in the dTSH group with venous TSH (v-TSH) levels of 620 mU/L according to whether late preterm infants born at gestational age (GA) 3536 weeks had risk factors.
Methods: The medical records of 810 neonates (414 boys) born at Seoul National University Hospital who had a normal neonatal screening test (NST) and underwent the first repeat venous blood test at 1021 days post birth were reviewed.
Results: Seventy-three (9.0%) neonates showed dTSH, defined as a v-TSH level ≥6.0 mU/L, 12 of whom (1.5%) were started on levothyroxine medication. A multivariate-adjusted model indicated that a low birth weight (LBW <2,000 g), a congenital anomaly, and exposure to iodine contrast media (ICM) were significant predictors for dTSH (all P < 0.05). Among these 73 dTSH infants, all 5 infants with TSH levels ≥20 mU/L began levothyroxine medication, and 6 of 16 infants with v-TSH levels of 1020 mU/L were indicated for levothyroxine, regardless of coexisting risk factors. However, only 1 of 52 infants with v-TSH levels of 610 mU/L who had a congenital anomaly was indicated for levothyroxine. All healthy late preterm infants, including LBW and multiple births, with v-TSH levels of 610 mU/L exhibited normal thyroid function.
Conclusions: dTSH was detected in 9.0% and levothyroxine was indicated in 1.5% of infants born at GA 3536 weeks, particularly those with a LBW, a congenital anomaly, or history of ICM exposure. Either levothyroxine or retesting is indicated for late preterm neonates with TSH levels ≥10 mU/L regardless of risk factors. If healthy preterm neonates show v-TSH levels of 610 mU/L, a second repeat test may not be necessary; however, further studies are required to set a threshold for retesting.