The American College of Obstetricians and Gynecologists has updated Practice Bulletin #159: Management of of Preterm Labor and Practice Bulletin #160: Premature Rupture of Membranes, and Committee Opinion #652: Magnesium Sulfate Use in Obstetrics published in the January 2016 edition of Obstetrics & Gynecology (membership required for access to practice bulletins).
These are interim updates to reflect a limited, focused change in gestational age at which to consider tocolysis or antenatal corticosteroids, based on the Obstetric Care Consensus No. 3: Periviable Birth. Obstet Gynecol 2015;126:e82–94