Recent recommendations from ATA guidelines to define the upper reference range for serum TSH in the first trimester match reference ranges for pregnant women in Rio de Janeiro

Abstract

In the population studied,TSH upper limit in the first trimester of pregnancy was above 2.5 mIU/L. The value of 3.6 mIU/L, found when iodine deficiency and thyroiditis (defined by antibodies and ultrasound characteristics) were excluded, matches recent ATA guidelines.