Association between ultrasound-based assessment of fetal head station and clinically assessed cervical dilatation.

Abstract

To describe the association between ultrasound-based determination of fetal head station and clinical assessment of cervical dilatation during active labor. From 427 women with singleton uncomplicated term pregnancies we obtained, during the active phase of labor, 907 pairs of measurements. Fetal head station and position were determined using the LaborPro system, based on position tracking and ultrasound imaging technology, and degree of cervical dilatation was determined by digital vaginal examination. The association between them was analyzed. The overall correlation between cervical dilatation and fetal head station was 0.64 (P < 0.001). Complete dilatation was observed in 78% of women with fetal head engagement, and in all women with a fetal head station of + 1.5 or more. There is good association between non-invasive ultrasound-based determination of fetal head station and clinically assessed cervical dilatation.