Management of fetal distress.

Since its introduction more than 20 years ago, continuous electronic FHR monitoring has become the standard in most modern obstetric units. Practitioners well versed in FHR pattern interpretation do not question the value of fetal monitoring. Not only does this modality detect hypoxia early in its evolution, but also it allows the opportunity to understand the physiology of the hypoxia and to intervene if necessary. Although nonrandomized studies demonstrate an improvement in the perinatal death rate with continuous monitoring, most randomized studies have failed to confirm this observation. Continuous fetal monitoring has been associated in several studies with an increase in the CS rate; however, concomitant changes in obstetric practice have also raised the incidence of CS, making the interpretation of to what degree fetal monitoring is responsible for this increase difficult. Other than this association with an increased CS rate, fetal monitoring seems to present few risks. A thorough understanding of basic fetal heart abnormalities is crucial to prevent unnecessary intervention; however, although quite sensitive, FHR monitoring remains nonspecific in predicting fetal metabolic acidosis. Fetal pulse oximetry is a recent development still undergoing investigation. The ability to measure fetal oxygen saturation during labor adds critical information about fetal status and refines the interpretation of abnormal FHR patterns. If approved by the US Food and Drug Administration, it has the potential to affect dramatically the practice of obstetrics.