Abstract

OBJECTIVE: Our purpose was to determine whether adding antenatal thyrotropin-releasing hormone to prenatal corticosteroids reduces the frequency of respiratory distress syndrome. STUDY DESIGN: A randomized, multicenter, double-blind, placebo-controlled trial was conducted of thyrotropin-releasing hormone (400 ?g intravenously every 8 hours four times) in women with singleton pregnancies <33 weeks of gestation who received antenatal betamethasone (12 mg intramuscularly every 24 hours two times). Neonates weighing <1.0 kg received prophylactic surfactant and those above that weight received rescue therapy. RESULTS: One hundred ninety women received thyrotropin-releasing hormone and 180 were given placebo. There were no differences in the frequency of respiratory distress syndrome (relative risk 1.17 [95% confidence interval 0.93 to 1.48]), use of oxygen at age 28 days (1.14 [0.80 to 1.62]), or neonatal mortality (1.05 [0.79 to 1.38]). Air leaks were more frequent in the thyrotropin-releasing hormone group (1.57 [1.23 to 2.01]). CONCLUSIONS: The combination of antenatal thyrotropin- releasing hormone and corticosteroids does not reduce the frequency of respiratory distress syndrome or improve the outcome of preterm neonates compared with the use of corticosteroids alone.