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 2 h 59 minutes vs 1 h 54 minutes; P = 0.001) and larger infants (mean 3723 g vs 3480 g, 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.