The effect of thyroxine and corticosteroids upon amniotic fluid fluorescence polarization: A randomized controlled study

The efficacy of glucocorticoid and intra amniotic thyroxine therapy on fetal lung maturity were compared in a randomized prospective clinical trial. Eighty two patients received either intra amniotic thyroxine (n = 36), or intra muscular Dexamethasone (n = 46). The Fluorescence Polarization (FP) of amniotic fluid measured prior to and one week following treatment were similar in the two groups. The rate of decrease in FP value per unit of time (dFP/dt) was identical in the T4 and corticosteroid treated patients and the proportion of immature FP values obtained was similar in the two groups. The effect of thyroxine therapy was more pronounced in pregnancies above 33 weeks gestation. Intra amniotic thyroxine therapy appeared to be as effective as glucocorticoids for the enhancement of fetal lung maturity. This therapeutic modality may be of particular use on pregnant subjects in whom a relative contra indication for the administration of steroids exists.