Electromyographic activity in cervices with very low Bishop score during labor.

OBJECTIVES

To investigate the activity of the smooth muscles in the cervix at the onset of induced labor and to further elucidate this activity in relation to uterine contractions and to the duration of the latent phase of labor, taking cervical ripeness into account.

METHODS

Cervical electromyographic (EMG) activity was studied at the onset of labor induced with amniotomy and oxytocin. Bipolar measurement of cervical electrical activity was performed. The root mean square of the cervical EMG activity and the intensity of intrauterine pressure in two groups of parturients with different cervical ripeness were compared.

RESULTS

The EMG activity was higher in the group with lower Bishop scores. We found a significant positive correlation between EMG activity and duration of the latent phase of labor.

CONCLUSION

Smooth muscles in the human cervix are active during labor and act to some extent independently of the uterine corpus.