Breech presentation affects 3% to 4% of term pregnancies. Because a fetus is more likely to be safely delivered vaginally from the vertex position, external cephalic version is a technique used by obstetricians to change the presentation of the fetus from breech to vertex. The obstetrician is balancing the risks of the version (umbilical cord compression, and fetal and/or maternal hemorrhage leading to urgent or emergent delivery) against the risks of a potentially difficult breech vaginal delivery (leading to urgent or emergent delivery). The procedure is typically scheduled after 38 weeks’ gestational to decrease the possibility of the fetus reverting back to a breech position and is sometimes performed with the adjunctive use of tocolytics.

Overall, external cephalic version is successful in 35% to 86% of nonlaboring, term parturients. Maternal and fetal factors that increase the chance of successful external cephalic version include that the patient is not obese, the cervix is not fully dilated, amniotic membranes are intact, the fetus is in a frank breech or transverse lie, there is normal amniotic fluid volume, the presenting part of the fetus has not entered the pelvis, and there is posterior positioning of the fetal back. Both obstetric and anesthesia staff also generally acknowledge that the success of external cephalic version may depend to a considerable degree on the skill and experience level of the obstetrician combined with the level of pain tolerated by the patient.

The question of whether the use of neuraxial anesthesia (spinal or epidural) facilitates successful external version and improves outcomes is an interesting and unanswered one. There is also the dilemma of what drug to use and how much to give. Most anesthesiologists tend to use “labor doses” for version, and because labor epidurals are quite routine in current anesthetic practice, the matter seems a simple one. When giving anesthesia for external version, however, for every pro there is a con. Patients are sometimes quite anxious about the procedure and fearful of the pain. Assuring the patient that she will have little, if any, pain, and then providing her with a painfree experience, can help the obstetrician perform the version with fewer maneuvers by providing a relaxed and reassured patient. However, removing pain as a limiting factor in the procedure may also increase the potential for a greater number of maneuvers and more aggressive attempts.
This may in turn increase the potential for significant complications, such as placental abruption. This is equally true if the patient is unable to feel pain from a resulting abruption or uterine rupture after the trial of external version is complete. Also, the risks of neuraxial anesthesia, including hypotension, infection, paresthesias, bleeding/epidural hematoma, subdural puncture headache, and, most important, fetal distress, are incurred by the patient in addition to the risks of the version. If the attempted version does result in a call for urgent or emergent delivery, it is advantageous for the patient, anesthesiologist, and obstetrician to have the block already in place and working, unless, of course, it is determined that the block contributed significantly to the inability to monitor the maternal vital signs or to the fetal difficulties. It is incumbent on the anesthesia provider to document before the version is attempted that the block is stable and the mother and fetus are at baseline.