Does occiput posterior position in the second stage of labour increase the operative delivery rate?

Objectives To assess the impact of occipito-posterior position in the second stage of labour on operative delivery. Methods Double-blinded prospective cohort study of ultrasound determined occiput-posterior position during the second stage of labour compared with occiput-anterior position. The primary outcome was operative (caesarean section, forceps or vacuum) delivery. Results A total of 68% (13/19) women in the occiput-posterior group, and 27% (39/141) in the occiput-anterior group had an operative delivery (unadjusted: P<0.001). Caesarean section was performed in 37% and 5%, respectively (P<0.001). The occiput-posterior group had a longer second stage (mean 2h 59minutes vs 1h 54minutes; P=0.001) and larger infants (mean 3723g vs 3480g, P=0.024). In the logistic regression, occiput-posterior position, nulliparity, abnormal second stage cardiotocograph and epidural analgesia were independent predictors for operative delivery. Conclusions Occiput-posterior position early in the second stage of labour is strongly associated with operative delivery. There is potential to explore interventions such as manual rotation.