505: Persistent breech presentation-A novel prognostic factor

Abstract

The success of external cephalic version (ECV) depends on several factors such as placental position, amniotic fluid index, unengaged presenting part, fetal weight, and operator experience. We sought to determine the importance of a new variable named “Persistent Breech Presentation” (PBP) as an independent prognostic factor for the success of ECV. A retrospective study from January 2008 to December 2018. We defined PBP when breech presentation was documented at each ultrasound evaluation from the routine anatomical survey at 18-23 weeks’ gestation up to ECV. We assessed variables that were considered favorable or unfavorable for ECV success. The primary outcome of the study was the success of ECV and the secondary outcome included mode of delivery. 1,271 women with breech presentation came for consultation. The average number of physician visits during which sonographic evaluation was performed was 4. Of the 1271 women that were included in the study, 684 (54%) underwent ECV at 37 weeks` gestation. Successful ECV was achieved in 489 cases (71.5%) but in only 7% (34 cases) of PBP (P< 0.0001). In patients with PBP and a composite of validated favorable conditions (posterior lying placenta, adequate amniotic fluid index, no uterine activity, average estimated fetal weight (, ECV succeeded in only 44 women (9%) (P< 0.0001). Of the 195 failed ECVs, 180 (92.3%) had PBP (P< 0.0001). Of the 44 women with PBP and successful ECV, only 12 (27.3%) had an uneventful vaginal delivery, 13 (29.5%) had an instrumental delivery and 19 (43.2%) had an emergency cesarean delivery mainly due to arrest of descent. No differences in cord entanglement or uterine anomalies were noted between PBP or non-PBP patients during Cesarean Section (CS). PBP is associated with a very low success rate of ECV (< 10%) and uncomplicated vaginal delivery (< 30%). PBP should be taken into consideration when counseling women for ECV.