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Am J Perinatol 1989; 6(3): 289-291
DOI: 10.1055/s-2007-999595
ORIGINAL ARTICLE

© 1989 by Thieme Medical Publishers, Inc.

Heart Rate Cyclicity During Labor in Healthy Term Fetuses

Boris M. Petrikovsky, Anthony M. Vintzileos, David J. Nochimson
  • Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Connecticut Health Center, Farmington, Connecticut
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Publication History

Publication Date:
04 March 2008 (online)

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ABSTRACT

Fifty-four intrapartum fetal heart rate (FHR) tracing were subjected to retrospective analysis of the presence, length, and frequency of cyclic changes in long-term variability (cyclicity). All patients had spontaneous uncomplicated labor and received no narcotics or analgesics. The following cycles were identified according the difference in long-term variability in terms of amplitude range: cycle A, 0 to 2.5 beats/min; cycle B, 3 to 5 beats/ min; cycle C, 6 to 10 beats/min; and cycle D, 11 to 20 beats/min. The frequency and length of FHR cycles was established in the latent, active phases and second stage of labor. Periods of diminished variability should be followed by fetal acid-base assessment only if their duration exceeds the established norms.

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