On December 15, 2018, the ACOG released a Practice Update regarding subcutaneous use of 17OHP rather than IM 17OHP for preterm birth prevention. Weekly IM injections of 17OHP were endorsed by the ACOG after the 2003 MEIS MFM Network clinical study demonstrated a reduced risk of preterm birth in women with prior preterm birth, with its use. In this podcast, we will review the ACOG practice update regarding subcutaneous rather than IM 17 OHP for preterm birth prevention.