Adverse neonatal outcomes result from a complex interplay of intrapartum events, antepartum complications, placental function or dysfunction, and uterine perfusion. Electronic fetal monitoring is widely utilized intrapartum to assess fetal status, to prevent adverse neonatal outcomes such as fetal asphyxia or cerebral palsy. Unfortunately, there is high intraobserver and interobserver variability when interpreting fetal heart rate tracings. In one study, obstetricians interpreted fetal heart rate tracings similarly in only 29% of cases. In 2008, terminology and nomenclature for electronic fetal monitoring were standardized at a workshop sponsored by the American College of Obstetricians and Gynecologists, the Society for Maternal-Fetal Medicine, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. This workshop defined variable decelerations as abrupt, visually apparent decreases in the fetal heart rate. The onset of the deceleration to the nadir should be less than 30 seconds. The decrease from the fetal heart rate baseline should be at least 15 beats per minute and should last for at least 15 seconds, but less than 2 minutes. Variable decelerations can be periodic, meaning they are associated with contractions, or they can be episodic and not associated with uterine contractions.