16: Can myometrial electrical activity identify preterm labor?

Article Outline

• Objective
• Study design
• Results
• Conclusion
• Copyright

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Objective 

We hypothesized that false and active labor in preterm pregnancy can be differentiated using myometrial electrical activity.

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Study design 

In a prospective study (IRB approved) patients with gestational age <37 reporting to Labor and Delivery for premature labor were recruited (with signed consent). Myometrial electrical activity of the uterine muscle was measured using a proprietary multi-channel EMG amplifier and a 3-dimensional non-invasive position sensor (EUM-100) with non-significant patient risk. Subjects were monitored for 30 minutes. Spontaneous premature delivery was defined as delivery within 2 weeks from time of test. An index score (1-5) for prediction of premature labor was developed: average period between contractions (in seconds); average power of contraction peaks (in watts) [The higher the energy, the higher the grade]; average movement of “center of gravity” (in mm). The computerized data that generated the index score were analyzed with the evaluator blinded to the clinical outcome. For further comparison to the EUM score, transvaginal cervical length, fetal fibronectin (FFN), and time interval from test to delivery were collected.

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Results 

64 patients consented to the study. Of tests performed, 18% scored 1 (0-2.9 watts), 27% scored 2 (3-6.9watts), 33% scored 3 (7-13.9watts), 11% scored 4 (14-19.9watts) and 9% scored 5 (20-high watts). An EUM score ≥4 identified 75% of patients delivering within 2 weeks regardless of tocolytic therapy. A score of ≤3 identified 72% of patients who failed to deliver within two weeks (p=0.002). Data on patients with gestational age ≤34 for single/combination of prediction tests is displayed below.

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Conclusion 

Our data suggests that measuring myometrial electrical activity may enhance identification of patients in true premature labor.