Transperineal ultrasound imaging in prolonged second stage of labor with occipitoanterior presenting fetuses: how well does the ‘angle of progression’ predict the mode of delivery?

This is the first report to document a strong relationship between an objective ultrasound marker (angle of progression) and the mode of delivery following prolonged second stage of labor with occipitoanterior fetal position. A predictive model using this parameter would allow better decision making regarding operative delivery for obstructed labor.