Birth weight and thyroxine-binding globulin in pre-eclampsia.

Plasma concentrations of thyroxine (T4) and thyroxine-binding globulin (TBG) as well as triiodothyronine uptake (T3U) were measured in 32 proteinuric pre-eclamptic patients and 24 normotensive pregnant women at similar gestations in the third trimester. The pre-eclamptic patients had slightly lower TBG, and significantly lower T4, concentrations, which were significantly correlated. They also had significantly lower infant birth weight which was correlated to the TBG and T3U values. There was no correlation between T4 and TBG or between birth weight and TBG or T3U in the normotensive women. It is likely that the correlation between TBG and birth weight in the pre-eclamptic patients reflects the severity of proteinuria in pre-eclampsia.