In the 6 trials combined in the Goldstein meta-analysis, only 279 women were treated with 17OHP and only 73 women had a preterm delivery. The NICHD study presented by Meis approximately doubles the world-wide experience, with 306 women under treatment, of whom 73 delivered prior to 35 wks. Yet, this study was not designed to have power to show a reduction in neonatal complications but only a reduction in preterm birth rates.