Management of persistent occiput posterior position: a substantial role of instrumental rotation in the setting of failed manual rotation.

Introduction: To compare the maternal and neonatal outcomes associated with Instrumental Rotation (IR) to operative vaginal delivery in occiput posterior (OP) position with Thierry's spatulas (TS), in the setting of failed manual rotation (MR).

Study Design: We led a prospective observational cohort study in a tertiary referral hospital in Toulouse, France. All women presenting in labor with persistent OP position at full cervical dilatation and who delivered vaginally after failed MR and with IR or OP assisted delivery were included from January 2014 to December 2015. The main outcomes measured were maternal morbidity parameters including episiotomy rate, incidence and severity of perineal lacerations, perineal hematomas and postpartum hemorrhage. Severe perineal tears corresponded to third and fourth degree lacerations. Fetal morbidity outcomes comprised neonatal Apgar scores, acidemia, fetal injuries, birth trauma and neonatal intensive care unit admissions.

Results: Among 9762 women, 910 (9.3%) presented with persistent OP position at full cervical dilatation and 222 deliveries were enrolled. Of 111 attempted IR, 97 were successful (87.4%). The incidence of anal sphincter injuries was significantly reduced after IR attempt (1.8% vs. 12.6%; p < 0.002). Both groups were similar regarding most fetal outcomes and no birth trauma occurred in our study population. In a multivariable logistic regression analysis, OP operative delivery was a significant risk factor of severe perineal lacerations (OR = 9.5; 95% CI: 2.05-44.05).

Conclusion: Our results support the use of IR in order to reduce perineal morbidity associated with OP assisted delivery, in the setting of a failed manual rotation.