The descent of the fetal head is not modified by mobile epidural analgesia: a controlled sonographic study.

The aim of our study was to assess the sonographic indices of fetal head progression obtained by three-dimensional ultrasound during the second stage of labor in women with and without mobile epidural analgesia. Sonographic volume data sets were obtained with a transperineal approach every 20 min from the beginning of the active second stage until delivery. The ultrasound parameters were calculated off-line from each volume and compared between women with and without epidural analgesia.