Amniotic fluid reverse triiodothyronine in normal and high risk pregnancies

The authors have dosed by radioimmunoassay the rT3 concentrations in the amniotic fluid of 12 normal pregnant women and of 25 women with high risk pregnancies at the same period of gestation. The average of the rT3 concentrations in the amniotic fluid of pregnant women affected by diabetes mellitus, EPH gestosis and with foetal growth, retardation, are not different from those found in the control group. In the patients affected by Rh isoimmunization, the rT3 levels are remarkably higher than those found in the control group. The rT3 highest levels found in the amniotic fluid of pregnant women affected by Rh isoimmunization could be due. 1) to a decreased transformation of rT3 in rT2 for an accentuated alteration of the sulphydryl groups: 2) to a need of blocking the pathway's conversion of T4 in T3 (hormone with great catabolic effect) in these foetuses already presenting an accentuated catabolism for the chronic hemolytic enemy and for the severe hepatic alterations.