Objective The purpose of this study was to characterize the noninvasi ve magnet ic field recordings of the uterine electrophysiological activity in patients rep orting onset of uterine contractions. Study design Transabdominal magnetomyograp hic (MMG) recordings were performed with the use of the SARA systems 151 prima ry magnetic sensors (CTF Systems Inc, Coquitlam, British Columbia, Canada). Elev en term and 4 preterm patients participated in the study. On all patients, cervi cal 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 ou r recordings. Of the 7 patients with peak activity below 8 pT, 5 failed to deliv er within 48 hours of the recordings. This observation reflects an increase in t he electrophysiologic activity of the myometrium as labor progresses. Conclusion MMG evaluation provides a new noninvasive meth od for the prediction of labor. Further studies are in progress to determine the temporal relationship of MMG changes with the onset of labor. Objective The purpose of this study was to characterize the noninvasi ve magnet ic field recordings of the uterine electrophysiological activity in patients rep orting onset of uterine contractions. Study design Transabdominal magnetomyograp hic (MMG) recordings were performed with the use of the SARA system’s 151 prima ry magnetic sensors (CTF Systems Inc, Coquitlam, British Columbia, Canada). Elev en term and 4 preterm patients participated in the study. On all patients, cervi cal dilation and outcomes were recorded. Results Of 8 patients having a peak MMG activity of 8 pT (pico Tesla), all but 1 delivered within 48 hours of ou r recordings. Of the 7 patients with peak activity below 8 pT, 5 failed to delivier within 48 hours of the recordings. This observation reflects an increase in t he electrophysiologic activity of the myometrium as labor progresses. Conclusion MMG evaluation provides a new noninvasive meth od for the prediction of labor. Further studies are in progres s to determine the temporal relationship of MMG changes with the onset of labor.