Serum thyroxin level during the first-trimester of pregnancy

Objective: The aim of this study was to assess the requirement of serum thyroxin levels during the early stage of the first trimester of pregnancy. Methodology: Serum thyroxin levels of 120 apparently healthy women were evaluated in Gorgan in northern Iran during 2007-08 by the enzyme linked immunosorbant assay (ELISA). Results: According to the reference intervals of our standard kit, 48% of the pregnant women in this study had elevated thyroxin levels. Conclusion: The findings of this study can be misleading, because it was based on the laboratory standard kit, women normal range, as general. Pregnant women require higher levels of thyroxin and therefore, a specific normal range for the first trimester of pregnancy should be established in each particular region.