A Prospective Randomized Study to Examine the Success Rate of External Cephalic Version for Breech Presentation at Term Presentation: Spinal Analgesia Versus No Analgesia

The rate of breech presentations in the general population of parturients has remained unchanged at 3%. However, the recent finding that the fetus has an increased morbidity during a vaginal delivery when compared with Cesarean section [1] has driven obstetricians towards the decision that all breech presentations will be delivered surgically. The morbidity of the mother with a breech presentation is not increased with a vaginal delivery; in fact the maternal morbidity associated with surgery is higher than after a vaginal delivery [2,3]. Subsequent pregnancies are automatically deemed high risk due to the presence of a uterine scar [4].

In an attempt to reduce the need for surgery with a breech presentation, the only option available in the current climate, where a vaginal delivery is out of the question, is to attempt to convert the fetal presentation from a breech to a vertex (head) presentation.

This technique may result in the premature onset of labor, which would require emergent surgery, and there is also a risk of placental abruption [5]. Following external cephalic version (ECV), the fetus may spontaneously return to the breech position. The success rates vary from 30% in nulliparous women, to 67% in multiparous women [6].

In an attempt to improve the success rates of ECV, authors have previously utilized regional anesthesia techniques [7-11]. Regional analgesia relaxes the stomach wall, and provides pain relief during the ECV procedure. The use of regional analgesia has claimed to increase the success rate of ECV to up to 80% [7]. However, other studies found no differences in success rates between the group which received regional analgesia and the group that did not [12]. All of these studies looked at women who have reached at least 36 weeks gestation. Despite the well-recognized differences in success rates between nulliparous and multiparous women, none of the studies that have examined regional analgesia with ECV have controlled for this factor in their studies. Thus the success rates, and any increase in success rates that is seen, may purely be a function of the number of multiparous women enrolled in the study.

This study will compare ECV separately in both a nulliparous and multiparous population, at term, and compare the success rates when spinal anesthesia is employed, versus no anesthesia. Success is defined as the conversion of a breech to vertex presentation.