Determination of fetal head station and position during labor: a new technique that combines ultrasound and a position-tracking system

Abstract

The purpose of this study was to compare the ultrasound-based LaborPro (Trig Medical Ltd, Yokneam, Israel) system determination of fetal head station and position with routine vaginal examination. This prospective study, which was conducted in 3 centers included 311 measurements that were performed in 166 singleton term pregnancies during the active phase of vertex, uncomplicated labor. Ultrasound-based position-tracking system calculations of fetal head station and position were compared with routine vaginal examination measurements. Comparison of vaginal examination with the system head station results revealed a mean absolute difference of 5.5 +/- 6.1 mm (n = 311). Vaginal examination head-position evaluation, within a 45 degrees interval, complied with the system in 35 of 87 cases (40.2%). Our data show that an ultrasound-based system can determine fetal head station and position during labor, when compared with vaginal examination, and requires minimal ultrasound skills. The limits of vaginal examination assessment of the head position are in agreement with published data.