For a study, researchers wanted to assess the possibility of a link between a novel variable, persistent breech presentation, and the success rate of the external cephalic version (ECV). This was a review of ECVs conducted between January 2008 and January 2019. All pregnant women who had an ECV at or after 37 weeks of pregnancy were included in the research group. The persistent breech presentation was defined as persistent breech presentation throughout all ultrasound tests between the anatomy scan at mid-pregnancy and the gestational week when ECV was tried. Women who had a cephalic presentation at least once on these ultrasonography tests were considered to have chronic breech presentation. The primary outcome was the ECV success rate, while the secondary outcome was the manner of delivery following a successful ECV.

During the research period, researchers found 1,271 women with breech presentation. They’d had a median of five (range 2–7) ultrasound exams. The external cephalic version was tried in 684 women (53.8%), with a 61.5% success rate. The external cephalic version was successful in 19.6% of those with persistent breech presentation (44/224), but not in 82.0% (377/460) of those without persistent breech presentation (P<.001). When compared to the nonpersistent breech presentation group, women with persistent breech presentation and successful ECV had a lower rate of vaginal delivery (27.3% vs 79%, P<.001) and a higher rate of instrumental (29% vs 13%, P<.001) and cesarean deliveries (43% vs 7%, P<.001). The rate of noninstrumental vaginal birth was 5.4% among women with persistent breech presentation, independent of ECV.

Women who presented in a persistent breach position had a high probability of ECV failure and a low incidence of spontaneous vaginal birth.