The physiologic and medical rationale for intrapartum fetal monitoring

In the United States and most industrialized countries, intrapartum fetal surveillance is performed primarily by electronic fetal heart rate monitoring. Following implementation of this technology into clinical practice, a reduction in perinatal mortality has been accompanied by a concomitant increase in the cesarean section rate to concerning levels. Although these trends are not solely due to one factor such as electronic fetal heart rate monitoring, it is well-recognized that this method of surveillance is hampered by subjectivity in interpretation and by a high false-positive (falsely nonreassuring) rate. The purpose of this review is to assess the physiologic rationale for intrapartum assessment, the significant limitations of current primary and ancillary monitoring methods, and the development of new technologies such as fetal oxygen saturation monitoring (pulse oximetry) that potentially hold great promise for the future.