Effectiveness of pulse oximetry versus fetal electrocardiography for the intrapartum evaluation of nonreassuring fetal heart rate.

OBJECTIVES To compare the effectiveness of pulse oximetry and fetal electrocardiography in the management of labor with nonreassuring fetal heart rate (NRFHR). STUDY DESIGN This randomized experimental study consisted of two arms. In group 1 we used pulse oximetry and in group 2 we used STAN® technology. The participants in each group were 90 pregnant women with a full-term singleton fetus in cephalic presentation and cardiotocographic tracings compatible with NRFHR. We compared the following variables: rate of cesarean delivery, indications for operative delivery due to NRFHR, and repercussions on the newborn's acid-base status. RESULTS The two groups differed significantly in the mode of delivery, with a cesarean delivery rate of 47.6% in group 1 vs. 30% in group 2 (p=0.032). The groups did not differ in the indications for ending labor due to NRFHR (62% vs. 61%, NS). In terms of neonatal outcomes, the 1-min Apgar score was 6 or lower in 17.8% of the group 1 neonates vs. 4.44% of the group 2 neonates (p<0.001). The groups also differed significantly in umbilical cord vein pH (7.23 vs. 7.27) and pCO₂ (57.27 vs. 46.86) at birth. CONCLUSIONS Fetal electrocardiography with the STAN® 21 system was more effective in detecting good fetal status and thus in identifying cases in which labor could proceed safely. Intrapartum surveillance with the STAN® 21 system reduced the rate of emergency cesarean delivery.