On October 25, 2019, the American Journal of Perinatology published the results of the PROLONG Trial. This study demonstrated no statistical difference in the co-primary outcome of preterm birth less than 35 0/7 weeks of gestation (P = 0.72) and neonatal composite index (P = 0.73) with 17-OHP use. Similarly, the rate of preterm birth less than 37 weeks and less than 32 weeks were not different. On October 25, 2019, the ACOG released a practice advisory about this. Let’s summarize this now.