Antenatal thyrotropin releasing hormone for fetal pulmonary maturation: Two concurrent randomised controlled trials. 1045

The combined effect of antenatal treatment with corticosteroids (CS) and thyrotropin releasing hormone (TRH) for the prevention of death, RDS and chronic lung disease has been studied in 6 completed trials. A meta-analysis of these trials suggested a beneficial effect but the confidence intervals were wide. Two double-blind randomised controlled trials of antenatal TRH in combination with CS were planned, one pragmatic in Europe (AT) and one explanatory trial (TN) in the Netherlands. The primary outcome of the AT trial was mortality and/or O2 dependency at 28 days (N=3800 women); for the TN trial RDS and/or death at 72 hrs (N=1050 women). The protocols were designed for a combined analysis. Inclusion criteria were threatened preterm labour (< 33 wks gestational age (AT), 24 - 30 wks (TN)) and an indication for CS. Treatment with TRH (400 μg iv) or placebo was given Q8h X4. All women received CS. The results of the Australian trial, and the preliminary results from trials conducted in Chile and the USA led to early closure of our two trials. At the time our trials stopped a total of 224 women had been recruited. Although there are still some missing data, the preliminary results are given below. From these data, the previously mentioned meta-analysis, and the USA and Chile trials, antenatal TRH cannot be recommended for clinical practice. Table