Magnesium sulfate is widely recommended for neuroprotection in pregnancies at risk of preterm delivery. However, the optimal gestational age for use is unclear. JAMA Associate Editor Melissa Simon, MD, MPH, and Caroline Crowther, MD, Liggins Institute, University of Auckland, discuss the use of magnesium sulfate at different gestational ages and potential benefit vs harms as reflected in the MAGENTA Trial. Related Content:

• Prenatal Intravenous Magnesium at 30-34 Weeks' Gestation and Neurodevelopmental Outcomes in Offspring