To measure the rates of thyroid gland imaging and levothyroxine (L-T₄) discontinuation and to assess whether discontinuation was monitored with thyroid-stimulating hormone testing in subjects with congenital hypothyroidism.

This is a retrospective analysis of claims data from the IBM MarketScan Databases for children born between 2010 and 2016 and continuously enrolled in a noncapitated employer-sponsored private health insurance plan or in Medicaid for ≥36 months from the date of the first filled L-T₄ prescription.

There were 263 privately insured and 241 Medicaid-enrolled children who met the inclusion criteria. More privately insured than Medicaid-enrolled children had imaging between the first filled prescription and 180 days after the last filled prescription (24.3% vs 12.9%; P = .001). By 36 months, 35.7% discontinued L-T₄, with no difference by insurance status (P = .48). Among those who discontinued, 29.1% of privately insured children and 47.7% of Medicaid-enrolled children had no claims for thyroid-stimulating hormone testing within the next 180 days (P = .01).

Nearly one-third of children with suspected congenital hypothyroidism discontinued L-T₄ by 3 years and fewer Medicaid-enrolled than privately insured children received timely follow-up thyroid-stimulating hormone testing. Future studies are indicated to understand the quality of care and developmental outcomes for children with congenital hypothyroidism and barriers to guideline adherence in evaluating for transient congenital hypothyroidism.