Background: Subclinical hypothyroidism (SCH) has been reported to be associated with adverse pregnancy outcomes, however universal screening and treatment is controversial.
Objectives: Our objectives were to determine population-specific pregnancy reference values (R1) for serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) at 14 weeks' gestation, along with the prevalence of SCH and thyroid peroxidase antibody (TPOAb).
Methods: This was a prospective hospital-based cohort study.