Table 1.

Recommendations From ATA and ACOG Regarding the Treatment of Maternal Hypothyroidism and Hypothyroxinemia in Pregnancy(3, 68)

Laboratory data	ATA	ACOG
TPO antibody negative and TSH >10 mIU/L	Treat with LT4	Treat with LT4 only if free T4 is low
TPO antibody positive and TSH > pregnancy-specific range (or 4 mIU/L)	Treat with LT4	Treat with LT4 only if free T4 is low
TPO antibody positive and 2.5 mIU/L < TSH < pregnancy-specific reference range (or 4 mIU/L)	Consider treatment with LT4	No treatment
TPO antibody negative and pregnancy-specific reference range (or 4 mIU/L) < TSH < 10 mIU/L	Consider treatment with LT4	Treat with LT4 only if free T4 is low
Isolated maternal hypothyroxinemia	No treatment	Not discussed

Abbreviations: ACOG, American College of Obstetrics and Gynecology; ATA, American Thyroid Association; LT4, levothyroxine; TPO, thyroid peroxidase.