Thyroid stimulating hormone (TSH) ≥2.5 mU/l in early pregnancy: Prevalence and subsequent outcomes

Using a TSH cut-off of 2.5 mU/l in keeping with European and US guidelines means that over 12% of women in this cohort would be classified as having subclinical hypothyroidism. Treatment and monitoring of these women would have major implications for planning of obstetric services.