External cephalic version (ECV) is a procedure performed to convert a breech or shoulder presentation into a cephalic one by manipulating the fetus through the mother’s abdominal wall and the anterior wall of the uterus. Its reported success rate is 30-80%, and Royal College of Obstetricians and Gynaecologists (RCOG) guidance suggests that overall success rates of 40% for nulliparous women and 60% for multiparous women should be possible.
Problems and special considerations
ECV is usually attempted at 36-37 weeks’ gestation; a fetus at earlier gestation is more likely to revert to a breech presentation subsequently since there is more room available, and since the procedure carries a risk of premature delivery a more mature gestation is preferable. On the other hand, the larger the fetus the more difficult it may be to achieve successful version, especially if the presenting part is engaged. If an ECV attempt fails at 36 weeks’ gestation, it is extremely unlikely the fetus will turn spontaneously.
Contraindications include multiple pregnancy (although ECV is occasionally used to turn the second twin), antepartum haemorrhage, placenta praevia, ruptured membranes, fetal abnormalities and factors that indicate caesarean section. Previous caesarean section, fetal growth restriction, pre-eclampsia and obesity are controversial relative contraindications. The mother should be nil-by-mouth in case a complication occurs. The fetus is monitored continuously, and with the mother in the tilted supine position, talcum powder is applied to the abdominal wall and rotationary pressure applied to the fetus while attempting to lift the presenting part out of the pelvis. Tocolytic drugs (e.g. β2-agonists) have been shown to increase the success rate of ECV.
There may be considerable discomfort, particularly if the mother is very tense, which reduces the chance of success. Various manoeuvres have been used in an attempt to improve the success and tolerability of ECV, including sedation (e.g. with benzodiazepines), nitrous oxide, remifentanil and regional analgesia, with the last being the only method shown to influence success. However, many obstetricians consider the degree of discomfort a useful indicator of when to stop the attempted procedure, and prefer to avoid the use of adjuncts.
In the UK, anaesthetists are rarely involved, although meta-analysis suggests that the success rate can be significantly improved with regional analgesia without an increase in complications. Current RCOG guidelines state that regional anaesthesia should not be routinely offered, but may be considered for a second attempt at ECV or when the mother requires improved analgesia. A maximum of 10 minutes is usually allowed before considering the attempt at version unsuccessful.
Apart from discomfort, complications of ECV include maternal or fetal bradycardia, onset of labour and placental abruption, with about 0.5% of cases requiring immediate caesarean section. Labour after successful ECV is also associated with a slight increase in delivery by instrumental delivery or caesarean section. Because of these possibilities, a clear discussion with the mother and her partner about the options, risks and timings is essential. It should also be remembered that breech presentation is more common in fetuses with other congenital abnormalities and in placenta praevia or uterine abnormalities.
Management options
From the anaesthetic viewpoint, awareness that ECV is being planned is usually the main issue, since anaesthetic input may be required at short notice. However, anecdotal experience suggests that many obstetricians perform ECV in clinics, wards or the delivery suite without routinely informing anaesthetists. If regional anaesthesia is requested, spinal and combined spinal-epidural are both appropriate techniques, with the usual attention paid to maintaining uteroplacental blood flow.
Key points
• External cephalic version has a reported success rate of 30-80%.
• Analgesia or sedation may occasionally be required.
• Regional analgesia improves the success rate but is uncommonly used in the UK.
• Complications include fetal distress, onset of labour and haemorrhage.
Further reading
Hutton EK, Hofmeyr G, Dowswell T. External cephalic version for breech presentation before term.
Cochrane Database Syst Rev 2015; (7): CD000084
Impey LWM, Murphy DJ, Griffiths M, Penna LK; Royal College of Obstetricians and Gynaecologists. External cephalic version and reducing the incidence of term breech presentation. Green-top Guideline 20a. BJOG 2017; 124: e178-92.
Khaw KS, Lee SW, Ngan Kee WD, et al. Randomized trial of anaesthetic interventions in external cephalic version for breech presentation. Br J Anaesth 2015; 114: 944-50.
Lim S, Lucero J. Obstetric and anesthetic approaches to external cephalic version. Anesthesiol Clin 2017; 35: 81-94.
Magro-Malosso ER, Saccone G, Di Tommaso M, Mele M, Berghella V. Neuraxial analgesia to increase the success rate of external cephalic version: a systematic review and meta-analysis of randomized controlled trials. Am J Obstet Gynecol 2016; 215: 276-86.