Narrow subpubic arch angle is associated with higher risk of persistent occiput posterior position at delivery

Abstract

A narrow SPA is associated with a higher risk of persistent OP position at delivery and of operative delivery. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Fetal head circumference and subpubic angle are independent risk factors for unplanned cesarean and operative delivery

“…SPA assessed on either 2D or 3D transperineal ultrasound has proved to be a reliable proxy of pelvic morphology . Narrow SPA values have been associated with the length of labor risk of operative delivery, shoulder dystocia and persistent occiput posterior position . The findings from this study confirm the association between maternal height and risk of UOD, with such risk being higher in women with a small stature .…”

Sonographic prediction of outcome of vacuum deliveries: a multicenter, prospective cohort study

“…In our study, all positions were included. The third cardinal movement is different in occiput posterior positions 48,49 and this might explain why angle of progression did not predict cesarean. Because varying cut-off levels for the angle of progression in predicting cesarean deliveries are suggested in previous studies (from 120-146 degrees), 14,45 we decided to investigate angle of progression as a continuous variable.…”

Fetal rotation during vacuum extractions for prolonged labor: a prospective cohort study

“…Spontaneous rotation is not only influenced by the position of the fetal head, but also by the position of the fetal spine (4). An android shape of the female pelvis with a narrow subpubic arch angle predisposes to persistent OP position (5). Ultrasound is found to be more accurate in diagnosing fetal position than digital examination (6,7).…”