Agreement between two- and three-dimensional transperineal ultrasound methods in assessing fetal head descent in the first stage of labor
Objective To study intraobserver repeatability and intermethod agreement between two- (2D) and three-dimensional (3D) transperineal ultrasound methods in assessing fetal head descent during the first stage of labor. Methods Fetal head descent was measured with transperineal ultrasound as the fetal head-perineum distance and the angle of progression in 106 primiparous women with prolonged first sta