TG and hypothyroidism: Pregnant women can have their thyroid hormones measured, with TSH and fT4 typically used to define subclinical hypothyroidism (TSH > 97.5th percentile, fT4 in normal reference range), overt hypothyroidism (TSH > 97.5th percentile and fT4 < 2.5th percentile), and hypothyroxinemia (TSH in normal reference range, fT4 < 2.5th percentile) [12].