Abstract
Objective
A critical analysis of the United States randomized controlled trial of fetal pulse
oximetry concluded that nonreassuring fetal heart rate patterns used for study entry
may have been a marker for dystocia. We prospectively studied nulliparous women in
labor whose progress was monitored with fetal pulse oximetry to examine the relationship
between nonreassuring fetal heart rate patterns and operative delivery for dystocia.
Study design
A prospective nonrandomized observational cohort study compared two distinct classes
of nonreassuring fetal heart rate patterns (class I: intermittent, mildly nonreassuring;
class II: persistent, progressive, and moderate to severely nonreassuring) among nulliparous
patients with the use of fetal pulse oximetry to confirm fetal well-being. Definitions
of dystocia included the cessation of labor progress in the first (3 hours) or second
(2 hours) stage of labor, despite adequate uterine activity that was assessed with
an intrauterine pressure catheter. Independent review confirmed the classification
of nonreassuring fetal heart rate patterns and study entry criteria.
Results
Two hundred seventy-four patients met study criteria and had sufficient information
for fetal heart rate tracing interpretation. Two hundred thirty-seven patients (86.5%)
were class II, and 37 patients (13.5%) were class I. The two classes of patients were
comparable in a variety of obstetric, demographic, and perinatal variables. Twelve
percent of all patients were delivered for nonreassuring fetal status. Significantly
more class II patients (22%) were delivered by cesarean for dystocia than were class
I patients (8%). Higher doses and a longer number of hours of oxytocin were required
among class II patients. Significantly more occiput posterior positions were noted
among all patients who underwent cesarean delivery for dystocia compared with other
modes of delivery.
Conclusion
Significantly nonreassuring fetal heart rate patterns predict cesarean delivery for
dystocia among nulliparous patients with normally oxygenated fetuses in a setting
of a standardized labor management protocol. This confirms the observations in the
randomized controlled trial of fetal pulse oximetry in the United States and may provide
insight into the treatment of nonprogressive labor in contemporary practice.
Keywords
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Article info
Publication history
Accepted:
June 26,
2003
Received in revised form:
June 9,
2003
Received:
April 9,
2003
Footnotes
☆Supported by Nellcor Perinatal Division of Tyco International, Pleasanton, Calif.
☆Reprints not available from the authors.
Identification
Copyright
© 2004 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
