Body
Introduction
A breech presentation occurs in 3–4% of all pregnant women at
term1. Since the publication of the Term Breech Trial
in 20002 which demonstrated excess neonatal mortality
as a consequence of breech vaginal delivery, cesarean delivery rates
have risen alarmingly3.
External cephalic version (ECV) is a procedure for modifying the fetal
position and achieving a cephalic presentation. The objective of the ECV
is to offer an opportunity for cephalic delivery to occur which, as
widely known, is safer than breech or cesarean section. The use of
external cephalic version in breech presentation, according to
WHO4, certainly reduces the incidence of cesarean
section, which is of special interest in those units where vaginal
breech delivery is not a common practice.
ECV is usually performed before the active labor period begins. Factors
associated with a higher ECV success rate include5–7:
multiparity, a transverse presentation, black race, posterior placenta,
amniotic fluid index higher than 10 cm.
Certain interventions have been related to helping in
ECV8 such as tocolysis, analgesia, empty bladder
before procedure9, or the introduction of a dedicated
experienced team10. Ritodrine has been reported as a
safe tocolytic agent and the drug that improves the most ECV success
rate8,11. Other tocolytic agents studied in ECV are
nifedipine8, atosiban8,
nitroglycerine12, or others
beta-agonist12.
About analgesia in ECV, some interventions have been analyzed such as
systemic opioids or spinal anesthesia. Spinal anesthesia techniques
improve the ECV success rate and pain after
procedure13–16. No differences are reported in Ethe
CV success rate when systemic opioids or spinal anesthesia are
compared13.
The introduction of an experienced dedicated team is not a completely
studied fact. Several studies reported a high ECV success rate when the
procedure is executed by a single operator17,18 or a
dedicated team5,10,19,20. Just one study has compared
a dedicated team with non-experienced gynecologists, midwives, and
residents10.
The main objective of this study is to compare ECV results when the
procedure is performed by an experienced dedicated team or by seniors
obstetricians who are not involved in a dedicated team. As a secondary
objective, predictor factors of ECV success are analyzed in both groups.
We hypothesized that an experienced dedicated team could have a higher
ECV success rate and a lower complication rate.
Methods
This was a longitudinal prospective analysis of ECV performed in ’Virgen
de la Arrixaca’ University Clinical Hospital in Murcia (Spain) between
1st of January of 2018 and 31st of
December of 2019. This center is the largest maternity department in
Spain with above 7.500 births per year. Informed written consent was
taken from the patients under study. The confidentiality of any
information pertaining to the patients was assured. No obligation on the
patients to participate in the study. Written informed consent was
obtained from all participants to publish their data. This study (intern
code: 2020-5-6-HCUVA) was approved by the ‘Research Ethics Committee’ of
‘Virgen de la Arrixaca’ University Hospital in June 2020.
From 1st of January of 2018 to 31stof September of 2019, the procedure was performed by two of the four
senior experienced obstetricians who composed the dedicated team for ECV
in the Maternal-Fetal Unit. In this study, this group is designed as
‘Group A’. The dedicated team for ECV in Maternal-Fetal Unit has more
than seven years of experience in ECV.
The members of the dedicated team for ECV were absent between
1st of October of 2019 and 31st of
December of 2019, and they were performed by two seniors obstetricians
specialized in obstetrical care. These seniors colleagues were not
involved in the dedicated team for ECV. In this study, this group is
designed as ‘Group B’.
Patients were recruited during the third-trimester obstetric evaluation
at 36 weeks gestation. Recruitment criteria were the same for Group A
and Group B. ECV was offered to every pregnant woman with non-cephalic
presentation and no absolute contraindication for vaginal delivery.
Women were deemed ineligible to undergo ECV in cases of severe
preeclampsia, recent vaginal bleeding, confirmed rupture of membranes,
and when an absolute indication for cesarean section was identified (eg
placenta previa).
In the consult, all pregnant women were asked about personal and
obstetric history. An ultrasound assessment for studying the fetal
position, fetal biometry, amniotic fluid, and placental position was
performed in the consult.
If the patient was eligible and informed consent was obtained, ECV is
performed at 37 weeks gestation. All patients were asked to fast for
eight hours before the procedure.
Procedure
ECV was performed following the same protocol in Group A and Group
B21,22. The procedure was carried out in the obstetric
operating room with the presence of an anesthesiologist and a midwife.
Before ECV was performed, pregnant women were evaluated by the
anesthesiologist. The patients were asked to empty their bladder. Just
before the procedure, 0.2 mg/min of ritodrine are intravenously
administered for 30 minutes.
In the operating room, maternal vital signs were monitored (heart rate,
EKG, temperature, noninvasive blood pressure, oxygen saturation). The
patient was positioned in Trendelenburg (15º) and administered 1-1.5
mg/kg of propofol22.
Two ECV attempts following the forward roll technique were performed by
two experienced obstetricians. Immediately after the procedure, fetal
well-being was assessed with continuous cardiotocograph register during
the following 4 hours. Anti‐D was given to rhesus‐negative women. 24
hours after the procedure, fetal well-being was reassessed with
continuous monitoring for one hour.
If any complication occurred immediately after the procedure, an urgent
cesarean section was performed. ECV is considered successful when a
cephalic presentation is achieved.
Outcome variables
ECV is considered successful when a cephalic presentation is achieved.
Intraversion cesarean is considered as any cesarean carried out during
the ECV or the first 24 hours after the procedure due to any
complication secondary to it (i.e., fetal compromise, cord prolapse,
vaginal bleeding, …).
Statistical Analysis
Data were recorded prospectively on all referrals. Data on pregnancy
outcomes were collected from hospital obstetric and neonatal records.
Continuous variables were assessed for normality with the Shapiro–Wilk
test.
The primary outcome variable was the incidence of external cephalic
version procedural success. The secondary outcome variable was the
incidence of intraversion cesarean section. Obstetric history,
anthropometric measurements, estimated fetal weight at
3rd trimester, placental location, and fetal
presentation underwent bivariate analysis using Student’s T-test or
Pearson’s chi-squared test to compare the characteristics of each group.
Subsequently, the primary and secondary outcome variables were compared
between both groups.
Afterward, taking primary and secondary outcome variables for each
group: all variables above mentioned with P-value <0.2 in
bivariate analysis were considered using a multivariable analysis
logistic regression model for both groups. In common with all logistic
regression analyses, this produced a model applicable to the dataset
from which it was generated.
All tests were two‐tailed and the level of statistical significance was
set at 0.05. Data analysis was performed using SPSS version 25.0 (SPSS
Inc., Chicago, Illinois) and RStudio version 1.2.5033: Integrated
Development for R (RStudio, Inc., Boston, Massachusetts), and R version
3.6.2 (https://www.r-project.org/. Accessed February 29, 2022).
Results
In total, 186 pregnant women underwent an ECV attempt. Of these, 150
(80.6%) were performed by Group A, and 36 (19.4%) were carried out by
Group B. 86 women were nulliparas (66.1%) and 36 (33.9%) women were
multiparas. Baseline characteristics are depicted in Table 1. Baseline
characteristics were comparable for Group A and Group B.
The overall ECV success rate was 68.8% (95% CI 61.9-75.1). ECV
outcomes and obstetric outcomes by Group are shown in Table 2.
The success rate of ECV increased from 47.2% (95% CI 31.7-63.2) in
Group B to 74.0% (95% CI 66.6-80.5) in Group A (Figure 1). The
greatest increase in the success rate of ECV was seen in nulliparas,
from 38.5% (95% CI 21.8-57.6) in group B to 69.1% (95% CI 59.4-77.6)
(Figure 1).
After successful ECV, 11 pregnant women (5.9%) showed breech
presentation at birth and they were planned cesarean section.
The total vaginal delivery rate after ECV increased from 41.2% (95% CI
25.9-57.9) in Group B to 56.1% (95% CI 48.9-63.9) in Group A. Overall,
the rate of planned cesarean after ECV decreased from 33.3% (95% CI
19.7-49.5) in Group B to 22.0% (95% CI 15.9-29.1) in Group A.
Multivariable logistic regression analysis showed that amniotic fluid
pocket (OR 1.08, CI 95% 1.04-1.13 P <0.001) was
associated with the success of ECV. Multiparity (OR 3.16, CI 95%
1.04-9.58 P <0.05) and lower maternal BMI (OR 0.86, 95%
CI 0.77-0.95 P <0.001) were associated with the success
of ECV (Table 3).
Over this period, 22 (11.8%) complications occurred, all during the 24
h following the procedure. Complications rate decreased from 22.2%
(95% CI 11.1-37.6) in Group B to 9.3% (95% CI 5.5-14.8) in Group A.
13 minor vaginal bleeding, five non-reassuring fetal heart rate pattern,
two preterm rupture of membranes, two chord prolapse and a maternal
bronchoaspiration during the procedure were reported.
One newborn was admitted to neonatal unit care due to minor respiratory
distress. This was a patient with a successful ECV, and afterward,
intrauterine growth restriction was diagnosed. Labor was induced with
dinoprostone and it was a spontaneous delivery with a cord blood pH =
7.28 and APGAR score at 1st minute of life = 8 and
APGAR at 5 minutes of life = 9. The newborn was discharged after two
days with no consequences.
One newborn was admitted to neonatal intensive unit care due to major
respiratory distress. This was a planned cesarean section two weeks
after unsuccessful ECV. It was an extremely difficult fetal extraction
during the cesarean section that needed a J-shaped incision for
achieving it. Arterial cord blood pH was 6.97, venous cord blood pH was
7.00, APGAR score at 1st minute of life = 1, and APGAR
at 5 minutes of life = 6. After 7 days, the newborn was discharged to
neonatal unit care, where she was admitted for 23 days. No complications
arose during the following year.
One patient suffered bronchoaspiration. The bronchoaspiration occurred
just after ending the ECV. The patient was admitted to the maternal unit
care with antibiotic treatment. Although a cephalic presentation was
achieved, finally a cesarean section was performed due to the
bronchoaspiration after 7 days with treatment. A female was born with
APGAR score at 1st minute of life = 9 and Apgar at 5
minutes of life = 10. Arterial cord blood pH was 7.932, venous cord
blood pH was 7.28. The patient and her newborn were discharged with no
sequelae.
Discussion
Main findings
The experience is considered crucial in medicine in general, and in
obstetrics particularly. Super-specialization in medicine improves the
experience acquisition and makes the daily work safer. It seems logical
that the introduction of a super-specialized team in ECV, would improve
the success rate and would make the procedure safer. National and
International Obstetrics organizations should not only support but also
lead specific formation and accreditation plans for External Cephalic
Version specialization for obstetricians, midwives, and
anesthesiologists in light of this and previous results.
In this study, the success rate of ECV increases from 47.2% (95% CI
31.7-63.2) to 74.0% (66.6-80.5%) with the introduction of a dedicated
team. The number needed to treat was 6.7, meaning that 6.7 ECVs
performed by the experienced dedicated ECV team led to one additional
vaginal delivery in comparison with ECVs performed by the non-dedicated
team. The creation of a dedicated experienced team of obstetricians to
perform ECV led to an increase in the success rate and a significant
decrease in the cesarean section rate overall.
If the results are compared in nulliparas, a greater increase is
reported from 38.5% (95% CI 21.8-57.6) in group B to 69.1% (95% CI
59.4-77.6).
Interpretation
Several studies have used analgesia 8,12–14,16,20,23and tocolysis8,11 to improve the ECV success rate. The
present study had remarkable procedure characteristics such us, as far
as we are concerned, it is the first study in which propofol is used for
ECV and what tocolysis concerned, ritodrine is administered for 30
minutes just before the procedure.
Although several prediction models for the success of ECV have been
developed, none of them included the experience of the operator as a
potential predictor for success24,25. Kim et al.
underlined the potential importance of operator experience by developing
a learning curve for ECV. To achieve an expected success rate of 50% in
nulliparas, approximately 57 ECV attempts are needed, and for a 70%
success rate, approximately 130 attempts are needed. In multiparas, only
eight to 10 cases would be necessary for an expected success rate of
50% and 70%, respectively 26.
Several studies have analyzed their results in ECV when it is performed
by a dedicated team: single-operator17,18 or dedicated
team5,10,19,27. Bogner et al. showed that the ECV
success rate depended not only on parity and gestational age but also on
performing physician 28.
It should be highlighted that the success rate of ECV in this study
continued to increase in the years after the introduction of the
dedicated team, without a change in team members. It may indicate the
development of a learning curve.
Other studies have focused on the effect of a dedicated
team10,27. Hickland et al. replaced their ECV
obstetrician with a weekly breech clinic every 15 days and showed an
increase in the success rate of ECV from 32.6% to 41.9% over 3 years27. Thissen et al. compared ECV performed by a
non-experienced team with their results after the introduction of a
dedicated team. They reported an increase in the ECV success rate
(39.8% to 59.66%) with the greatest increase in
nulliparas10.
Previous studies have tried to elucidate fetal and maternal factors that
can predict the ECV result 6,24,25,29,30. Normal or
high amniotic fluid volume, multiparity, BMI<35
Kg/m2, reduced bladder volume, fetal transverse lie,
and increased estimated fetal weight are predictive of the success of
ECV in several studies9,25,29. The present study found
that normal to high amniotic fluid volume, multiparity, and lower BMI was
associated with the success of ECV.
ECV is considered to be a safe procedure for achieving a cephalic
presentation. Two studies analyzed ECV complications rate in dedicated
team31,32. Beuckens et al. reported 47.2% of ECV
success and 2.63% of complications during the 48 hours next to the
procedure. Rodgers et al. reported a success rate of 35% for nulliparas
and 62% for multiparas and an ECV complication rate of 4.73%. In both
studies, ECV was performed without analgesia nor tocolysis. The present
study found that an experienced dedicated team decreases ECV
complications rate from 22.2% (95% CI 11.1-37.6) to 9.3% (95% CI
5.5-14.8) with the introduction of ECV dedicated team.
Super-specialization in obstetrics is essential for improving results
and maintaining safety in procedures. ECV is an effective procedure for
reducing the cesarean section rate and offering a chance for a vaginal
delivery. When ECV is performed by experienced obstetricians a reduction
in complications rate and an increase in success rate are
observed10. Although how experience influences in ECV
have already been analyzed, experienced dedicated team was compared with
residents or non-experienced obstetricians10. This
study has compared the results, in terms of effectiveness and safety,
between the dedicated team and experienced senior obstetricians.
The introduction of a dedicated team not only supposes an advantage in
comparison with residents or other colleges but also with other
experienced obstetricians. Super-specialization in ECV, in the light of
this study, should be enhanced by nationals and internationals
obstetrics and gynecology associations.
Some key questions still unanswered, such as, the learning curve needed,
the type of anesthetic technique, the type of tocolytic drug, etc.
Besides, clinical trials are needed to evaluate definitively the
effectiveness of super-specialization in ECV. without the potential bias
that could affect observational studies.
Strengths and Limitations
A strength of this study is the fact that it is the first prospective
cohort study to assess the influence of an experienced dedicated team on
the success rate of ECV in comparison with senior experienced
obstetricians. This is the first study in which propofol is used for
sedation in patients who underwent ECV. It should be also highlighted
that in the present study ritodrine is administered for 30 minutes just
before the procedure. There were no significant differences in patient
and obstetric characteristics making selection bias less likely.
This study has some limitations. First, the number of women who
underwent ECV in a non-dedicated team is small, which may affect the
power of statistical analysis. However, differences observed in the
present study, despite the lack of power, are consistent. Due to the
differences in complications rate, it should be not ethical to increase
patients recruited in a non-dedicated team in this study. Besides, the
learning curve cannot be evaluated in this study due to the absence of
temporal analysis.
Conclusion
ECV is a safe and effective procedure. The introduction of an
experienced dedicated team improves the ECV success rate. Multiparity,
lower BMI, and normal or high amniotic fluid volume have been associated
with an increase in the ECV success rate. The introduction of an
experienced dedicated team reduces the ECV complications rate. ECV
super-specialization plan should be led by national and international
obstetrics organizations.
Contribution to Authorship:
J Sánchez-Romero, RM Gallego-Pozuelo helped to record data, performing
an ultrasound scan, and to design the study. F Araico-Rodríguez, JE
Blanco-Carnero, A Nieto-Díaz and ML Sánchez-Ferrer helped to record data
and to design the study. F Araico-Rodríguez and J Herrera-Giménez helped
to design the study.
Funding statement:
This research did not receive any specific grant from funding agencies
in the public, commercial, or not-for-profit sectors.
Ethical statement: This study was approved on the 30thof April of 2020 by the Clinical Research Committee of the ’Virgen de la
Arrixaca’ University Clinical Hospital (2020-5-6-HCUVA). Written
informed consent was obtained from all participants.
Reference
1 Hofmeyr GJ, Kulier R, West HM. External cephalic version for breech
presentation at term. Cochrane Database Syst Rev 2015; :
CD000083.
2 Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR.
Planned caesarean section versus planned vaginal birth for breech
presentation at term: a randomised multicentre trial. The Lancet2000; 356 : 1375–83.
3 Lee HC, El-Sayed YY, Gould JB. Population trends in cesarean delivery
for breech presentation in the United States, 1997-2003. Am J
Obstet Gynecol 2008; 199 : 59.e1-59.e8.
4 Hindawi I. Value and pregnancy outcome of external cephalic version.East Mediterr Health J Rev Sante Mediterr Orient Al-Majallah
Al-Sihhiyah Li-Sharq Al-Mutawassit 2005; 11 : 633–9.
5 Melo P, Georgiou EX, Hedditch A, Ellaway P, Impey L. External cephalic
version at term: a cohort study of 18 years’ experience. BJOG Int
J Obstet Gynaecol 2019; 126 : 493–9.
6 Isakov O, Reicher L, Lavie A, Yogev Y, Maslovitz S. Prediction of
Success in External Cephalic Version for Breech Presentation at Term.Obstet Gynecol 2019; 133 : 857–66.
7 Grootscholten K, Kok M, Oei SG, Mol BWJ, van der Post JA. External
cephalic version-related risks: a meta-analysis. Obstet Gynecol2008; 112 : 1143–51.
8 Cluver C, Gyte GML, Sinclair M, Dowswell T, Hofmeyr GJ. Interventions
for helping to turn term breech babies to head first presentation when
using external cephalic version. Cochrane Database Syst Rev 2015;
: CD000184.
9 Levin G, Rottenstreich A, Weill Y, Pollack RN. The role of bladder
volume in the success of external cephalic version. Eur J Obstet
Gynecol Reprod Biol 2018; 230 : 178–81.
10 Thissen D, Swinkels P, Dullemond RC, van der Steeg JW. Introduction
of a dedicated team increases the success rate of external cephalic
version: A prospective cohort study. Eur J Obstet Gynecol Reprod
Biol 2019; 236 : 193–7.
11 Levin G, Ezra Y, Weill Y, Kabiri D, Pollack RN, Rottenstreich A.
Nifedipine versus ritodrine during external cephalic version procedure:
a case control study. J Matern-Fetal Neonatal Med Off J Eur Assoc
Perinat Med Fed Asia Ocean Perinat Soc Int Soc Perinat Obstet 2019; :
1–6.
12 Katz D, Riley K, Kim E, Beilin Y. Comparison of Nitroglycerin and
Terbutaline for External Cephalic Version in Women Who Received
Neuraxial Anesthesia: A Retrospective Analysis. Anesth Analg2019; published online April 8. DOI:10.1213/ANE.0000000000004155.
13 Sullivan JT, Grobman WA, Bauchat JR, et al. A randomized
controlled trial of the effect of combined spinal-epidural analgesia on
the success of external cephalic version for breech presentation.Int J Obstet Anesth 2009; 18 : 328–34.
14 Mancuso KM, Yancey MK, Murphy JA, Markenson GR. Epidural analgesia
for cephalic version: a randomized trial. Obstet Gynecol 2000;95 : 648–51.
15 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.
16 Chalifoux LA, Bauchat JR, Higgins N, et al. Effect of
Intrathecal Bupivacaine Dose on the Success of External Cephalic Version
for Breech Presentation: A Prospective, Randomized, Blinded Clinical
Trial. Anesthesiology 2017; 127 : 625–32.
17 Levin G, Rottenstreich A, Weill Y, Pollack RN. External cephalic
version at term: A 6‐year single‐operator experience. Birth 2019;46 : 616–22.
18 Levin G, Rottenstreich A, Weill Y, Pollack RN. Late preterm versus
term external cephalic version: an audit of a single obstetrician
experience. Arch Gynecol Obstet 2019; 300 : 875–80.
19 Burgos J, Rodríguez L, Cobos P, et al. Management of breech
presentation at term: a retrospective cohort study of 10 years of
experience. J Perinatol 2015; 35 : 803–8.
20 Burgos J, Pijoan JI, Osuna C, et al. Increased pain relief
with remifentanil does not improve the success rate of external cephalic
version: a randomized controlled trial. Acta Obstet Gynecol Scand2016; 95 : 547–54.
21 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.
22 Velzel J, de Hundt M, Mulder FM, et al. Prediction models for
successful external cephalic version: a systematic review. Eur J
Obstet Gynecol Reprod Biol 2015; 195 : 160–7.
23 Kok M, van der Steeg J, van der Post J, Mol B. Prediction of Success
of External Cephalic Version after 36 Weeks. Am J Perinatol 2011;28 : 103–10.
24 Kim SY, Han JY, Chang EH, et al. Evaluation of the learning
curve for external cephalic version using cumulative sum analysis.Obstet Gynecol Sci 2017; 60 : 343.
25 Hickland P, Gargan P, Simpson J, McCabe N, Costa J. A novel and
dedicated multidisciplinary service to manage breech presentation at
term; 3 years of experience in a tertiary care maternity unit. J
Matern Fetal Neonatal Med 2018; 31 : 3002–8.
26 Bogner G, Xu F, Simbrunner C, Bacherer A, Reisenberger K.
Single-institute experience, management, success rate, and outcome after
external cephalic version at term. Int J Gynecol Obstet 2012;116 : 134–7.
27 Ebner F, Friedl TWP, Leinert E, et al. Predictors for a
successful external cephalic version: a single centre experience.Arch Gynecol Obstet 2016; 293 : 749–55.
28 Burgos J, Cobos P, Rodriguez L, et al. Clinical score for the
outcome of external cephalic version: A two-phase prospective study:
Clinical score for external cephalic version. Aust N Z J Obstet
Gynaecol 2012; 52 : 59–61.
29 Beuckens A, Rijnders M, Verburgt-Doeleman G, Rijninks-van Driel G,
Thorpe J, Hutton E. An observational study of the success and
complications of 2546 external cephalic versions in low-risk pregnant
women performed by trained midwives. BJOG Int J Obstet Gynaecol2016; 123 : 415–23.
30 Rodgers R, Beik N, Nassar N, Brito I, de Vries B. Complications of
external cephalic version: a retrospective analysis of 1121 patients at
a tertiary hospital in Sydney. BJOG Int J Obstet Gynaecol 2017;124 : 767–72.
Tables
Table 1 - Characteristics of pregnant women who underwent
external cephalic version (ECV). Data presented as mean or % (number
(n)). P-value < 0.05 in bold, when comparing characteristics
between Group A and B, T-student test for normally distributed
variables, and Chi-squared for categorical variables. BMI: Body Mass
Index. ECV: External Cephalic Version. CS: Cesarean Section. EFW:
Estimated Fetal Weight.