Elevation of serum Thyroxine level during early stage of first trimester of pregnancy

The aim of this study was to assess, the requirement of serum thyroxin level during early stage of first trimester of pregnancy. Serum thyroxin of 120 apparently healthy women was measured in Gorgan northern Iran during 2007- 08 using Enzyme,linked Immunossorbant assay(ELISA). According to the reference intervals of our standard kit, 48% of pregnant women in this study shown to have elevated thyroxin level. The findings of this study can be misleading because it was based on the laboratory standard kit, normal range for women, as general. Pregnant women require higher level of thyroxin. Therefore specific first trimester of normal range for pregnancy should be established in each particular region