An external labor-onset monitor that differentiates true labor from braxton-hicks-type contractions: preliminary findings

Abstract

Objective: To obtain parameters that differentiate true labor from Braxton-Hicks (BH) contractions in a simplified manner by processing the frequency spectrum of uterine electromyograms (EMG).Methods: This is an ongoing open study in patients recruited from women coming for scheduled antenatal appointments or for labor and delivery at Morton Hospital. The beginning and end of each EMG burst were determined. A power spectral density calculation was performed and integrated to give a parameter (DELTA) indicative of true labor (positive DELTA) or BH-type (negative DELTA) contractions. These results were compared with delivery within 36 hours.Results: Patients who had three consecutive positive DELTA values delivered within 36 hours (even though clinical measures of labor were negative), whereas those with three consecutive negative DELTA values did not. Patients who were obese (body mass index >34) or had a vaginal examination before the EMG measurement were excluded.Conclusions: Preliminary results indicate that the use of a labor-onset monitor may enable physicians to differentiate true labor from BH-type contractions, thereby determining to which patients exhibiting signs of preterm labor, tocolytic agents should be given.