Abdominal electromyography may predict the response to tocolysis in preterm labor

Abstract

Objective: To determine whether abdominal electromyography can predict the response to tocolysis in pregnant women in preterm labor.

Study design: This study was carried out at the Department of Obstetrics and Gynecology, Menofyia University Hospital in Egypt. Fifty pregnant women in preterm labor who fulfilled the inclusion criteria were enrolled. Baseline abdominal electromyography was performed. Tocolysis in the form of hexoprenaline sulphate infusion was started for all women and electromyography was repeated after 24h in responders but only after 6h in non responders. The receiver operating characteristics curve was drawn to calculate specificity of the electromyography at 100% sensitivity. Results were tabulated and statistically analyzed.

Results: Forty women responded to tocolysis by delaying delivery for more than 48 h. There was a significant reduction in the frequency of uterine contractions after tocolysis (3.76 ± 0.92 versus 2.32 ± 2.05 contractions per 10 min; P<0.001). Similar significant reductions affected the duration and amplitude of uterine action potentials (25.08 ± 9.74 versus 14.4 ± 17.16s; P<0.001, 40.8 ± 25.89 versus 28.32 ± 29.38 mV; P<0.001). At a sensitivity of 100% and using ROC curve, abdominal electromyography of amplitude of 82 mV lasting for 30s or more had a specificity of 90%, positive and negative predictive values of 67% and 95%, and a diagnostic accuracy of 88% in predicting preterm labor.

Conclusion: Abdominal electromyography may predict the response to tocolysis in preterm labor.