[Assessment of pre-term uterine contractions by characterization of the power spectra of abdominal surface potentials (ASP)].
The prognosis of pre-term labor in the absence of complications such as PROM is dependent on the strength of the uterine contractions, which are dependent on the sensitivity of the myometrium, expressed in terms of bio-electric potentials. Our electromyography were obtained from pregnant ewes, and these were correlated with abdominal surface potentials (ASP) obtained from human volunteers, to see if impending premature labor could be detected and the prognosis predicted. 1) The EMG tracings obtained from pregnant ewes were submitted to a power spectrum analysis. 2) EMG tracings revealed an increase in power output with the advance of labor, but power spectra varied with the stage of labor. 3) Uterine contractions not leading to cervical ripening had a low power output with a low frequency range. 4) Ewes in true labor had EMG's at a high power output of low frequency waves. 5) Ewes in pre-term labor leading to cervical ripening had power outputs similar to ewes in true labor, but the power spectra of the former were wider in range. 6) ASP tracing revealed an increasing power output with increasing uterine contractile activity and power spectra correlated well with the EMGs obtained from ewes. In conclusion, since ASP findings were in good correlation with EMGs obtained directly from the myometrium, we hope that this method may be developed into a practical non-invasive method for detecting and assessing uterine contractions.
Ebisawa
H
H
Department of Obstetrics and Gynecology, Nihon University School of Medicine, Tokyo.
Matsuura
M
M
Takagi
S
S
Satoh
K
K
D000005:Abdomen / Q000502:physiology; D000200:Action Potentials; D000818:Animals; D004576:Electromyography; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007752:Obstetric Labor, Premature / Q000503:physiopathology*; D011247:Pregnancy; D012756:Sheep; D014590:Uterine Contraction