Table 4.

Proposed changes to the ATA 2017 recommendations with supporting studies published in 2017 and 2018.

ATA 2017 recommendation 29	Proposed changes (Underlined)
LT4 therapy is recommended for  – TPOAb-positive women with a TSH greater than the pregnancy-specific reference range  Strong recommendation, moderate-quality evidence  – TPOAb-negative women with a TSH greater than 10.0 mIU/L  Strong Recommendation, low quality evidence	LT4 therapy is recommended for  – TPOAb-positive women with a TSH greater than the pregnancy-specific reference range  Strong recommendation, moderate-quality evidence  – TPOAb-negative women with a TSH greater than 10.0 mIU/L  Strong Recommendation, low quality evidence
LT4 therapy may be considered for  – TPOAb-positive women with TSH concentrations >2.5 mIU/L and below the upper limit of the pregnancy-specific reference range  Weak recommendation, moderate-quality evidence  – TPOAb-negative women with TSH concentrations greater than the pregnancy-specific reference range and below 10.0 mIU/L  Weak recommendation, low-quality evidence LT4 therapy is not recommended for  – TPOAb-negative women with a normal TSH  Strong recommendation, high-quality evidence	LT4 therapy may be considered for  – TPOAb-positive women with TSH concentrations >2.5 mIU/L and below the upper limit of the pregnancy-specific reference range  Weak recommendation, moderate-quality evidence  – TPOAb-negative women with TSH concentrations greater than the pregnancy-specific reference range and below 10.0 mIU/L diagnosed in the first trimester or earlier Weak recommendation, moderate-quality evidence LT4 therapy is not recommended for  – TPOAb-negative women with a normal TSH  Strong recommendation, high-quality evidence  – TPOAb-negative women with TSH concentrations > 2.5 mIU/L and below 10.0 mIU/L diagnosed in the second trimester or later  Weak recommendation, high-quality evidence
Supporting studies	Finding
Casey et al. (24)	No difference in child IQ at 5 years or adverse pregnancy outcomes in treated vs. untreated women with subclinical hypothyroidism in pregnancy. Treatment initiated in 2nd trimester.
Hales et al. (25)	No difference in child IQ at 9.5 years in treated vs. untreated women with subclinical hypothyroidism in pregnancy. Treatment initiated in 2nd trimester.
Nazarpour et al. (23)	Significant reduction in preterm delivery rate in treated TPOAb-negative women with TSH > 4.0 mIU/L and normal fT4 index compared to untreated women. Treatment initiated soon after first prenatal visit.
ATA 2017 recommendation 21 section	Proposed changes (Underlined)
Insufficient evidence exists to determine whether LT4 therapy improves the success of pregnancy following ART in TPOAb-positive euthyroid women. However, administration of LT4 to TPOAb-positive euthyroid women undergoing ART may be considered given its potential benefits in comparison to its minimal risk. In such cases, 25–50 μg of LT4 is a typical starting dose. Weak recommendation, low-quality evidence	LT4 therapy is not recommended for TPOAb-positive euthyroid women undergoing ART. Weak recommendation, moderate-quality evidence
Supporting studies	Finding
Wang et al. (52)	No difference in miscarriage rate, clinical pregnancy rate, live birth rate or preterm delivery rate between levothyroxine treated, TPOAb-positive euthyroid women undergoing ART and those who received no treatment.

Changes are highlighted by underlined text.

ATA, American Thyroid Association; LT4, Levothyroxine; TPOAb, Thyroid peroxidase antibody; TSH, Thyroid stimulating hormone; fT4, Free thyroxine; ART, Assisted reproductive technology.