Screening for Delayed Thyroid Stimulation Hormone Rise and Atypical Congenital Hypothyroidism in Infants Born Very Preterm and Infants with Very Low Birth Weight

Bret Nolan; Cherry Uy; Lisa Stablein; Fayez Bany-Mohammed

doi:10.1016/j.jpeds.2024.113974

Screening for Delayed Thyroid Stimulation Hormone Rise and Atypical Congenital Hypothyroidism in Infants Born Very Preterm and Infants with Very Low Birth Weight

J Pediatr. 2024 Feb 22:269:113974. doi: 10.1016/j.jpeds.2024.113974. Online ahead of print.

Authors

Bret Nolan¹, Cherry Uy¹, Lisa Stablein², Fayez Bany-Mohammed³

Affiliations

¹ Division of Neonatology, Department of Pediatrics, University of California Irvine, Orange, CA.
² UC Irvine Medical Center High-Risk Infant Follow-up Program, Department of Pediatrics, University of California Irvine, Orange, CA.
³ Division of Neonatology, Department of Pediatrics, University of California Irvine, Orange, CA. Electronic address: fbanymoh@hs.uci.edu.

PMID: 38401790
DOI: 10.1016/j.jpeds.2024.113974

Abstract

Objective: To determine among infants born very preterm (VPT) or with very low birth weight (VLBW) the incidence of alterations in thyroid function and associated comorbidities; the incidence of atypical congenital hypothyroidism (CH) requiring thyroxine therapy; and reference ranges for rescreening at 1 month of age.

Study design: A retrospective review of infants born VPT or with VLBW and admitted to UC Irvine Medical Center between January 1, 2012, and December 31, 2020. Repeat thyroid screening was obtained at 1 month of life (+10 days). Infants with thyroid-stimulating hormone (TSH) >5 μIU/mL or free thyroxine <0.8 ng/dL underwent follow-up testing and endocrinology consultation. Initial newborn screening (NBS) and repeat thyroid screening data were collected via chart review. Demographic data and short-term outcomes were abstracted from the California Perinatal Quality Care Collaborative database.

Results: In total, 430 patients were included; 64 of 429 patients (14.9%) had TSH >5 μIU/mL and 20 of 421 patients (4.8%) had free thyroxine <0.8 ng/dL. Logistic regression analysis identified small for gestational age (P = .044), patent ductus arteriosus (P = .013), and late-onset sepsis (P = .026) as risk factors associated with delayed TSH rise. Atypical CH requiring treatment through neonatal intensive care unit discharge was diagnosed in 6 patients (incidence of 1.4%); none were identified by NBS. The 90th percentile TSH for infants with extremely low birth weight (<1000 g) was 7.2 μIU/mL, and the 95th percentile for those with birth weight of 1000-1500 g was 6.1 μIU/mL; using these cutoff values identified all infants diagnosed with atypical CH with 100% sensitivity and 90%-95% specificity.

Conclusions: Abnormal thyroid function is common in infants born preterm. Those infants, including some with atypical CH, are missed by NBS. We recommend repeat thyroid screening with TSH at 1 month of age in infants born VPT or infants with VLBW to identify CH that may require therapy.

Keywords: VLBW infants; atypical hypothyroidism; congenital hypothyroidism; delayed TSH rise.