OC13.03: Sonographic prediction of mode of delivery: a multicentre, prospective cohort study

The aim of the study was to assess if ultrasound measurements of fetal position and station can predict mode of delivery in nulliparous women with prolonged second stage of labour. We performed a prospective cohort study in nulliparous women at term with prolonged second stage of labour from 2013–2016 in seven European maternity units. Fetal head position and station were determined using transabdominal and transperineal ultrasound respectively. Women were included and examined with ultrasound and head-perineum distance was measured when the birth attendant diagnosed prolonged second stage of labour after at least 45 minutes of active pushing and vacuum extraction was considered. The mode of delivery was evaluated using receiver-operating characteristics curves and descriptive statistics. 222 women were included in the study. The head-perineum distance was associated with spontaneous delivery with area under the curve 83% (95% CI 77–89%) and was associated with Caesarean with area under the curve 83% (95% CI 74–92%). In women with head-perineum distance ≤35mm, 7/181 (3.9%) were delivered by Caesarean versus 9/41 (22.0%) in women with head-perineum distance >35 mm (p <0.01). Ultrasound assessed position was occiput anterior (OA) in 73%. Only 3/138 (2.2%) of fetuses in OA position and head-perineum distance ≤35 mm versus 6/17 (35.3%) with non-OA position and head-perineum distance >35 mm were delivered by Caesarean. Supporting information can be found in the online version of this abstract Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.