Selective screening for thyroid dysfunction in pregnant women: How often do low-risk women cease to be treated following the new guidelines of the American Thyroid Association?

OBJECTIVE: Universal screening for thyroid dysfunction in pregnant women is not recommended by the American Thyroid Association (ATA) or the American Association of Clinical Endocrinologists (AACE). This study evaluated the frequency of pregnant women that would have an indication for levothyroxine (L-T4) according to the new ATA/AACE guidelines among low-risk women without an indication for screening with TSH. SUBJECTS AND METHODS: The sample consisted of 412 pregnant women ranging in age from 18 to 30 years. These women were considered to be at low risk for thyroid dysfunction according to ATA/AACE and would not be candidates for screening with TSH. Anti-thyroid peroxidase antibodies (TPOAb) and TSH were measured. Women who had TSH > 2.5 mIU/L or TPOAb in the first trimester were submitted to subsequent evaluations in the second and third trimester. RESULTS: In the first trimester, none of the pregnant women would have L-T4 therapy “recommended” and treatment would be “considered” in only two. In the second trimester, pregnant women with positive TPOAb or TSH > 2.5 mIU/L in the first trimester (n = 30) were reevaluated. L-T4 treatment would be “recommended” in only one woman and would be “considered” in two others. The 28 women that were not treated in the second trimester were reevaluated in the third trimester, but none of them would have L-T4 “recommended”. CONCLUSION: The findings of the study suggest that selective screening, recommended by ATA/AACE does not result in a significant loss of pregnant women with an indication for L-T4 treatment.