Intrapartum transperineal ultrasound as a predictor of instrumentation difficulty with vacuum-assisted delivery in primiparous women

AbstractObjectives: To assess the capability of different intrapartum transperineal ultrasound parameters to predict the difficulty of vacuum extraction. This is a prospective observational study performed between 04/2012 and 03/2013 on 72 primiparous-women, ≥37-weeks with singleton pregnancies at full dilatation that underwent transperineal ultrasound before vacuum placement for foetal extraction. Working in a transperineal longitudinal plane we evaluated: progression-angle, progression-distance and head direction; in a transverse plane: midline-angle and head-perineum distance. The vacuum extractions were classified as easy-group (EG) (≤3 vacuum pulls), difficult/impossible-group (DG)(≥4 pulls). Occiput-posterior presentations were not assessed.Results: Fifty-two (52) patients were studied (26 patients per study group). No differences were observed in obstetric, neonatal or intrapartum characteristics between the study groups, with the following exceptions: new-born (NB) weight (3147 g versus 3540 g) an...