External Cephalic Version (ECV)
Throughout the entire pregnancy, the fetus is constantly changing positions, but as the pregnancy approaches the 36 -38 week mark, a baby will typically assume a head down position before birth. This is sometimes referred to as a vertex position. On occasion, the baby will not be in a head down position at the time of labor. Doctors call this a non-vertex presentation. When the baby is bottom first, it is called breech. When the baby is neither head first or bottom first, it is often called transverse.
The Problems of Non-Vertex Presentation
A non-vertex presentation can complicate a delivery as either being undeliverable or dangerous to the baby’s health. A transverse position will not allow the baby to fit into the birth canal, so the baby cannot be delivered vaginally. A breech position may fit into the birth canal, but the width of the baby’s hips is less than the baby’s head which can create a situation where the hips may deliver but the head is trapped in the birth canal. Another problem with non-vertex presentations is the risk of the umbilical cord falling into the birth canal ahead of the baby. Should this happen, the baby’s source of oxygen may be comprised causing an emergency delivery by cesarean section.
As a result, labor is NOT recommended for non-vertex presentations. Instead, cesarean delivery is recommended if the problem presentation cannot be resolved.
The Solution for Non-Vertex Presentation
As already mentioned, cesarean delivery is recommended for persistent abnormal presentation at the time of labor. While cesarean delivery can be safe, most patients and doctors would prefer a vaginal delivery for its increased safety, and easier recovery. On occasion, your obstetrician my recommend a procedure to flip the baby to a head down (vertex) position. The procedure is called External Cephalic Version (ECV) or just, version.
How ECV is Performed ?
The technique may vary between doctors, but in most cases, ECV is performed at Women’s Hospital after 36 weeks. An epidural is often used to make the mother comfortable and a medicine, such as terbutaline, is given to let the uterus relax. Under ultrasound guidance, the obstetrician places their hands on the mother’s abdomen to manipulate the baby into a head down position. Literature reports that ECV is successful 58% of the time.
Risks of ECV
The risk of a complication of ECV is low and both mother and baby are monitored for problems after the procedure. The procedure may cause the rupture of the bag of water or cause labor. There is a risk that the umbilical cord will become compressed by the change in the baby’s position which could impair oxygen to the baby. Such a complication would result in emergent cesarean section. Injury to uterus or the placenta is very rare. There is always the risk that it doesn’t work and a cesarean section would be schedule at 39 weeks or later.
Who’s a Candidate for ECV ?
A singleton pregnancy (no twins) at least 36 weeks that is not in labor and whose water has not broken. The obstetrician may exclude mothers who have had a prior C-section or if the amniotic fluid appears to be low. At any rate, the decision to proceed with ECV is based on the preferences of the patient and the obstetrician.
For more info, consider; American College of Obstetricians and Gynecologists (2000, reaffirmed 2012). External cephalic version. ACOG Practice Bulletin No. 13. Obstetrics and Gynecology, 95(2): 1–7