RMOS Study : Impact of Manual Rotation of Occiput Posterior Position on Operative Delivery Rate

Introduction:

The frequency of fetuses in occiput posterior position during labor is approximately 20 %, in which 5% remain occiput posterior at the end of labor. Occiput posterior position is associated with higher risks of caesarean deliveries and operative vaginal deliveries. The manual rotation to promote rotation from a posterior to an anterior position has been proposed to reduce the extraction rate. There is no randomised trial comparing the effect of manual rotation and expectant management. We propose a protocol for a prospective, monocentric, randomised controlled clinical trial in order to show that the rate of spontaneous vaginal delivery is higher with manual rotation of occiput posterior position than with an expectative management.

Methods:

Every 37 weeks with a singleton pregnancy with a clinical occiput posterior position suspicion confirmed by a transabdominal ultrasound at full dilatation will be eligible. Participants will be randomised to either prophylactic manual rotation (experimental group) or expectative management (control group). Based on an alpha value of 0.05 and gaining 20% for spontaneous vaginal delivery, 238 participants will need to be enrolled.

The primary outcome will be spontaneous vaginal delivery. Secondary outcomes will be operative delivery rate (caesarean section , vacuum or forceps deliveries), significant maternal and perinatal mortality/morbidity.

Analysis will be by intention-to-treat averaging a 24-month period.