External cephalic version (ECV) is a process by which a breech baby can sometimes be turned from buttocks or foot first to head first. It is a manual procedure that is recommended by national guidelines for breech presentation of a pregnancy with a single baby, in order to enable vaginal delivery. It is usually performed late in pregnancy, that is, after 36 gestational weeks, preferably 37 weeks, and can even be performed in the early stages of childbirth.
Medical use
ECV is one option of intervention should a breech position of a baby be found after 36 weeks gestation. Other options include a planned caesarian section or planned vaginal delivery.
Following successful ECV, with the baby turned to head first, there is a less than 5% chance of the baby turning spontaneously to breech again.
Evidence of complications of ECV from clinical trials is limited, but ECV does reduce the chance of breech presentation at birth and caesarian section. The 2015 Cochrane review concluded that "large observational studies suggest that complications are rare".
Typical risks include umbilical cord entanglement, abruption of placenta, preterm labor, premature rupture of the membranes (PROM) and severe maternal discomfort. Overall complication rates have ranged from about 1 to 2 percent since 1979. While somewhat out of favour between 1970 and 1980, the procedure has seen an increase in use due to its relative safety.
Successful ECV significantly decreases the rate of cesarean section, however, women are still at an increased risk of instrumental delivery (ventouse and forceps delivery) and cesarean section compared to women with spontaneous cephalic presentation (head first).
Technique
The procedure is undertaken by either one or two physicians and where emergency facilities to undertake instrumental delivery and caesarian section are at hand. Blood is also taken for cross-matching should a complication arise.
The procedure usually lasts a few minutes and is monitored intermittently with CTG. With a covering of ultrasonic gel on the abdomen to reduce friction, The procedure is discontinued if maternal distress, repeated failure or fetal compromise on monitoring occurs.
There is some evidence to support the use of tocolytic drugs in ECV. Given by injection, tocolytics relax the uterus muscle and may improve the chance of turning the baby successfully. This is considered safe for the mother and baby, but can cause the mother to experience facial flushing and a feeling of a fast heart rate.
Following the procedure, a repeat CTG is performed and a repeat ultrasound will confirm a successful turn. Justus Heinrich Wigand published an account of ECV in 1807 and the procedure was increasingly accepted following Adolphe Pinard's demonstration of it in France. In 1901, British obstetrician, Herbert R. Spencer, advocated ECV in his publication on breech birth. In 1927, obstetrician George Frederick Gibberd, reviewed 9,000 consecutive births around Guy's Hospital, London. Following his study, he recommended ECV, even if it failed and needed to be repeated and even if it required anaesthesia.