Prediction of labor in term and preterm pregnancies using non-invasive magnetomyographic recordings of uterine contractions.

OBJECTIVE

The purpose of this study was to characterize the noninvasive magnetic field recordings of the uterine electrophysiological activity in patients reporting onset of uterine contractions.

STUDY

DESIGN

Transabdominal magnetomyographic (MMG) recordings were performed with the use of the SARA system's 151 primary magnetic sensors (CTF Systems Inc, Coquitlam, British Columbia, Canada). Eleven term and 4 preterm patients participated in the study. On all patients, cervical dilation and outcomes were recorded.

RESULTS

Of 8 patients having a peak MMG activity exceeding 8 pT (pico Tesla), all but 1 delivered within 48 hours of our recordings. Of the 7 patients with peak activity below 8 pT, 5 failed to deliver within 48 hours of the recordings. This observation reflects an increase in the electrophysiologic activity of the myometrium as labor progresses.

CONCLUSION

MMG evaluation provides a new noninvasive method for the prediction of labor. Further studies are in progress to determine the temporal relationship of MMG changes with the onset of labor.