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

Eur J Obstet Gynecol Reprod Biol. 2011 Dec;159(2):333-7. doi: 10.1016/j.ejogrb.2011.09.021. Epub 2011 Oct 5.


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.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid-Base Imbalance / etiology
  • Adult
  • Apgar Score
  • Carbon Dioxide / blood
  • Cesarean Section
  • Electrocardiography
  • Extraction, Obstetrical
  • Female
  • Fetal Blood
  • Fetal Distress / blood
  • Fetal Distress / diagnosis*
  • Fetal Distress / physiopathology
  • Fetal Monitoring / methods*
  • Heart Rate, Fetal*
  • Humans
  • Hydrogen-Ion Concentration
  • Infant, Newborn
  • Male
  • Oximetry
  • Pregnancy
  • Severity of Illness Index
  • Young Adult


  • Carbon Dioxide