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Am J Perinatol 2001; 18(3): 137-140
DOI: 10.1055/s-2001-14522
ORIGINAL ARTICLE

Copyright © 2001 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

Correlation of External and Internal Monitoring of Uterine Activity in a Cohort of Term Patients

A. M. Miles, M. Monga, K. S. Richeson
  • Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Houston Medical School
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Publication History

Publication Date:
31 December 2001 (online)

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ABSTRACT

External tocodynamometry (ET) and intrauterine pressure monitoring (IUPC) are commonly used to assess uterine contractile activity. It is believed that ET does not accurately document contraction amplitude. However, no direct comparison of ET and IUPC has been published in term patients. Our objective was to determine the correlation between frequency, duration, and amplitude as measured by ET and IUPC.

Twenty patients between 36 and 41 weeks' gestation were enrolled during active spontaneous labor. Uterine contractions were recorded simultaneously by ET and IUPC for 2 hours. ET and IUPC data were compared using the Spearman correlation coefficient and the Wilcoxon signed-rank test. The median body mass index (BMI) of the patient population was 31.8 kg/m2 (range 22.2 to 42.3). There was good correlation of contraction frequency measured by ET and IUPC (r = 0.75, p = 0.001), but poor correlation of both contraction amplitude (r = 0.26) and duration (r = 0.27). ET and IUPC assessment of uterine contractile activity, specifically contraction amplitude and duration, do not appear to correlate in a population of moderately obese patients. This suggests that ET should not exclusively be relied upon in this population to assess uterine contractile activity during labor.

KEYWORD

External tocodynamometry - intrauterine pressure monitoring - uterine activity

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