Should we stop prescribing IM progesterone to women with a history of preterm labor?

YES, we should stop the routine prescribing of IM progesterone to prevent preterm delivery. A 2003 randomized controlled trial (RCT) found that weekly intramuscular (IM) 17 hydroxyprogesterone (17-OHP) for women with a singleton pregnancy and a history of spontaneous preterm delivery decreased the preterm delivery rate by 34% (strength of recommendation [SOR]: B, single RCT). However, the follow-up 2020 PROLONG RCT did not find that 17-OHP prevents preterm birth or improves neonatal outcomes. This held true for subgroup analyses (SOR: B, single larger RCT). (Notably, though, the PROLONG study had very few Black participants when compared with the 2003 study.)The US Food and Drug Administration (FDA) has recommended withdrawing 17-OHP from the market. The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) have released statements supporting shared decision-making with women regarding the prescribing of 17-OHP for preterm delivery prevention (SOR: C, expert opinion).