Predictors for a successful external cephalic version: a single centre experience

Prediction Models for Successful External Cephalic Version: An Updated Systematic Review

OBJECTIVE

 To review the decision aids currently available or being developed to predict a patient's odds that their external cephalic version (ECV) will be successful.

STUDY DESIGN

 We searched PubMed/MEDLINE, Cochrane Central, and ClinicalTrials.gov from 2015 to 2022. Articles from a pre-2015 systematic review were also included. We selected English-language articles describing or evaluating models (prediction rules) designed to predict an outcome of ECV for an individual patient. Acceptable model outcomes included cephalic presentation after the ECV attempt and whether the ECV ultimately resulted in a vaginal delivery. Two authors independently performed article selection following PRISMA 2020 guidelines. Since 2015, 380 unique records underwent title and abstract screening, and 49 reports underwent full-text review. Ultimately, 17 new articles and 8 from the prior review were included. Of the 25 articles, 22 proposed one to two models each for a total of 25 models, while the remaining 3 articles validated prior models without proposing new ones.

RESULTS

 Of the 17 new articles, 10 were low, 6 moderate, and 1 high risk of bias. Almost all articles were from Europe (11/25) or Asia (10/25); only one study in the last 20 years was from the United States. The models found had diverse presentations including score charts, decision trees (flowcharts), and equations. The majority (13/25) had no form of validation and only 5/25 reached external validation. Only the Newman-Peacock model (United States, 1993) was repeatedly externally validated (Pakistan, 2012 and Portugal, 2018). Most models (14/25) were published in the last 5 years. In general, newer models were designed more robustly, used larger sample sizes, and were more mathematically rigorous. Thus, although they await further validation, there is great potential for these models to be more predictive than the Newman-Peacock model.

CONCLUSION

 Only the Newman-Peacock model is ready for regular clinical use. Many newer models are promising but require further validation.

KEY POINTS

· 25 ECV prediction models have been published; 14 were in the last 5 years.. · The Newman-Peacock model is currently the only one with sufficient validation for clinical use.. · Many newer models appear to perform better but await further validation..

Clinical Factors Associated with Intrapartum Presentation Change after Mechanical Cervical Ripening

OBJECTIVE

The use of mechanical cervical ripening with balloon devices is common during induction of labor; however, there is risk for displacement of the fetal presenting part during its insertion. This study sought to investigate the clinical risk factors associated with an intrapartum presentation change from cephalic to noncephalic presentation after mechanical cervical ripening.

STUDY DESIGN

Data were obtained from the Consortium on Safe Labor, a multicenter retrospective study that abstracted detailed labor and delivery information from electronic medical records in 19 hospitals across the United States. All women with fetal cephalic confirmed position on admission undergoing induction of labor with mechanical cervical ripening were included. Women who had a cesarean delivery for noncephalic presentation were compared with women who had a vaginal delivery or cesarean delivery for other indications. Models were adjusted for nulliparity, multiple gestation, and gestational age.

RESULTS

A total of 3,462 women met inclusion criteria, with 1.3% (n = 46) having an intrapartum presentation change from cephalic to noncephalic presentation after mechanical cervical ripening. Those who had a cesarean delivery for an intrapartum presentation change were more likely to be nulliparous (82.6 vs. 65.4%, p = 0.01), less than 34 weeks' gestation (6.5 vs. 1.3%, p = 0.02), and have twins (6.5 vs. 1.2%, p = 0.02). In adjusted analysis, twins were associated with an increased odds of cesarean delivery for intrapartum presentation change (adjusted odds ratio [aOR]: 4.43; 95% confidence interval [CI]: 1.25-15.77), whereas multiparity reduced the odds (aOR: 0.38; 95% CI: 0.17-0.82).

CONCLUSION

Nulliparity and multifetal gestation are associated with a cesarean delivery for an intrapartum presentation change after mechanical cervical ripening.

KEY POINTS

· Intrapartum presentation change after mechanical cervical ripening is low at 1.3%.. · Nulliparity and multifetal gestation are associated with a cesarean delivery for presentation change.. · There were no significant differences in neonatal morbidity by delivery status to delivery type..

Predictive Factors for Successful Vaginal Delivery after a Trial of External Cephalic Version: A Retrospective Cohort Study of 946 Women

OBJECTIVE

Our aim was to find the factors which predict a vertex presentation of vaginal delivery (VD) in women who are admitted for a trial of external cephalic version (ECV).

STUDY DESIGN

This is a retrospective cohort study of women who underwent a trial of ECV and delivered between November 2011 and December 2018 in a single tertiary center. The main outcome measure was successful VD of a fetus in the vertex presentation. Women who achieved VD in the vertex presentation or underwent cesarean delivery were compared on the basis of variety of predictive factors. Adverse neonatal and maternal outcomes were reported. Logistic regression was used for the multivariate analysis.

RESULTS

A total of 946 women were included; 717 (75.8%) women had a successful ECV and 663 (70.1%) women had a VD in the vertex presentation. Parous women had 79.3% VD rate (570/719) and nulliparous women had 41.0% VD rate (93/227). Women with an amniotic fluid index (AFI) of 50 to 79, 80 to 200, and >200 mm had 34.8, 71.0, and 83.1% VD rate, respectively. Parous versus nulliparous women had an adjusted odds ratio (aOR) of 5.42 (95% confidence interval [CI]: 3.90-7.52, p < 0.001), women with AFI 50 to 79 mm compared with AFI 80 to 200 mm had an aOR of 0.21 (95% CI 0.12-0.37, p < 0.001), and women with an AFI >200 mm compared with AFI 80 to 200 mm had an aOR of 1.74 (95% CI: 1.03-2.92, p = 0.037) to achieve VD. The final prediction model for the chances of a VD based on data on admission for ECV was reported. The Hosmer-Lemeshow test was used to evaluate the goodness of fit of the model (p = 0.836).

CONCLUSION

Being parous and having an AFI >200 mm are positive independent predictive factors for achieving VD of a vertex presenting fetus after ECV. Whereas AFI 50 to 79 mm is a negative independent predictive factor.

KEY POINTS

· The goal of ECV is to achieve a vertex VD.. · Predictors for ECV success might not predict a VD.. · Parity & AFI independently predict a VD after ECV..

Factors influencing the effect of external cephalic version: a retrospective nationwide cohort analysis

OBJECTIVE

This study aims to assess the factors associated with the success and failure rate of the external cephalic version (ECV) in breech fetuses. Secondary outcomes were fetal presentation in labor and mode of delivery.

METHODS

This cross-sectional study examined the live birth certificates from 2003 through 2020 from US states and territories that implemented the 2003 revision. A total of 149,671 singleton pregnancies with information about ECV success or failure were included. The outcome was ECV success/failure, while the exposures were possible factors associated with the outcome.

RESULTS

The successful ECV procedures were 96,137 (64.23%). Among the successful ECV procedures, the prevalence of spontaneous vaginal delivery was 71.63%. Among the failed ECV procedures, 24.74% had a cephalic presentation at delivery, but 63.11% of these pregnancies were delivered by cesarean section. Nulliparity, female sex, low fetal weight centile, high pre-pregnancy BMI, high BMI at delivery, and high maternal weight gain during pregnancy were associated with an increased ECV failure (p < 0.001). African American, American Indian and Alaska Native race categories were significant protective factors against ECV failure (p < 0.001). Maternal age had a U-shape risk profile, whereas younger maternal age (< 25 years) and old maternal age (> 40 years) were significant protective factors against ECV failure (p < 0.001).

CONCLUSIONS

A high prevalence of successful ECV procedures and subsequent spontaneous vaginal delivery were found. The present results found nulliparity, maternal race, maternal age, female fetal sex, low fetal weight, and maternal anthropometric features correlated to ECV results. These findings can potentially improve the knowledge about the factors involved in ECV, allowing more informed counseling to the women undergoing this procedure.

Predictive factors for successful external cephalic version with regional anesthesia

AIM

We aimed to investigate predictive factors of successful external cephalic version (ECV) using regional anesthesia.

METHODS

In this retrospective study, we included women who underwent ECV at our center from 2010 to 2022. The procedure had been conducted using regional anesthesia and the administration of intravenous ritodrine hydrochloride. The primary outcome was the success of ECV, which was defined as the rotation from a non-cephalic to a cephalic presentation. Primary exposures were maternal demographic factors and ultrasound findings at ECV. To determine predictive factors, we conducted a logistic regression analysis.

RESULTS

Of 622 pregnant women who underwent ECV, missing data on any variables (n = 14) were excluded and the remaining 608 were analyzed. The success rate during the study period was 76.3%. Multiparous women had significantly higher success rates than primiparous women (adjusted odds ratio [OR]: 2.06 [95% confidence interval (CI): 1.31-3.25]). Women with a maximum vertical pocket (MVP) of <4 cm had significantly lower success rates than those with 4 cm < MVP ≤6 cm (OR: 0.56 [95% CI: 0.37-0.86]). The non-anterior placental location was associated with higher success rates than the anterior placental location (OR: 1.46 [95% CI: 1.00-2.17]).

CONCLUSIONS

Multiparity, MVP >4 cm, and non-anterior placental locations were associated with successful ECV. These three factors could be useful for patient selection for successful ECV.

The Effect of External Cephalic Version on Fetal Circulation: A Prospective Cohort Study

External cephalic version (ECV) is a cost-effective and safe treatment option for breech presentation at term. Following ECV, fetal well-being is assessed via a non-stress test (NST). An alternative option to identify signs of fetal compromise is via the Doppler indices of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV). Inclusion criteria were an uncomplicated pregnancy with breech presentation at term. Doppler velocimetry of the UA, MCA and DV were performed up to 1 h before and up to 2 h after ECV. The study included 56 patients who underwent elective ECV with a success rate of 75%. After ECV, the UA S/D ratio, UA pulsatility index (PI) and UA resistance index (RI) were increased compared to before the ECV (p = 0.021, p = 0.042, and p = 0.022, respectively). There were no differences in the Doppler MCA and DV before or after ECV. All patients were discharged after the procedure. ECV is associated with changes in the UA Doppler indices that might reflect interference in placental perfusion. These changes are probably short-term and have no detrimental effects on the outcomes of uncomplicated pregnancies. ECV is safe; yet it is a stimulus or stress that can affect placental circulation. Therefore, careful case selection for ECV is important.

External Cephalic Version-A Chance for Vaginal Delivery at Breech Presentation

Background and Objectives: In recent years, the rate of caesarean section (CS) has increased constantly. Although vaginal breech delivery has a long history, breech presentation has become the third most common indication for CS. This study aims to identify factors associated with the success of external cephalic version (ECV), underline the success rate of ECV for breech presentation and highlight the high rate of vaginal delivery after successful ECV. Material and Methods: This retrospective observational study included 113 patients with singleton fetuses in breech presentation, who underwent ECV from January 2016 to March 2021 in the Clinic of Obstetrics and Gynecology, Diakonieklinikum Schwäbisch Hall, Germany. Maternal and fetal parameters and data related to procedure and delivery were collected. Possible predictors of successful ECV were evaluated. Results: The success rate of ECV was 54.9%. The overall rate of vaginal birth was 44.2%, regardless of ECV outcome. The vaginal birth rate after successful ECV was 80.6%. Overall, 79.0% of women with successful ECV delivered spontaneously without complications, 19.4% delivered through CS performed during labor by medical necessity, and 1.6% delivered through vacuum extraction. ECV was performed successfully in three of the four women with history of CS. Gravidity, parity, maternal age, gestational age, fetal weight, and amniotic fluid index (AFI) were significantly correlated with the outcome of ECV. Conclusions: ECV for breech presentation is a safe procedure with a good success rate, thus increasing the proportion of vaginal births. Maternal and fetal parameters can be used to estimate the chances of successful ECV.

A prospective study using an individualized nomogram to predict the success rate of external cephalic version

To establish a clinical-based nomogram for predicting the success rate of external cephalic version (ECV) through a prospective study. This was a single-center prospective study that collected eligible breech pregnant women. 152 participants were enrolled in the training cohort, who received ECV procedures performed by a single operator. We used the training cohort to establish regression equations and prediction models. These variables include maternal factors (age, operation gestational age, pre-pregnancy BMI (Body Mass Index), operation BMI, BMI increase, multipara), ultrasound factors (fetal weight estimation, amniotic fluid index, placental location, type of breech presentation, spinal position), and anesthesia. Univariate and multivariable analyses were used to screen the factors affecting the success of ECV. A nomogram scoring model was established based on these factors. And C-index, DCA (Decision Curve Analysis) and calibration curve, Hosmer-Lemeshow test was used to verify the prediction effect of the model. Finally, 33 participants were enrolled in the testing cohort who received ECV with an unrestricted operator. We used C-index, DCA (decision curve analysis), and Hosmer-Lemeshow to verify the application value of the prediction model. The calibration curves and ROC curves of both the training cohort and testing cohort are plotted for internal and external validation of the model. The ECV success rate of the training cohort was 62.5%. Univariate analysis showed that the predictors related to the success rate of ECV were age, BMI increase value, AFI (amniotic fluid index), breech type, placental location, spinal position, anesthesia, and multipara. The prediction thresholds of the corresponding indexes were calculated according to the Youden index. Multivariate logistic regression analysis showed that BMI increase ≥ 3.85 kg/m2, AFI ≥ 10.6 cm, anesthesia, multipara, and non-anterior placenta were independent predictors of ECV success. Through the internal and external validation, it is confirmed that the model has a good calibration and prediction ability. Our nomogram has a good ability to predict the success rate of ECV.

External cephalic version at 38 weeks' gestation at a specialized German single center

Introduction

Cesarean section (CS) rates are increasing worldwide. One constant indication is the breech presentation at term. By offering external cephalic version (ECV) and vaginal breech delivery CS rates can be further reduced.

Objective

This study aimed to analyze the ECV at 38 weeks of gestation with the associate uptake rate, predicting factors, success rate, and complications at a tertiary healthcare provider in Germany specializing in vaginal breech delivery.

Methods

We conducted a prospective cohort study with retrospective data acquisition. All women with a singleton fetus in breech presentation presenting after 34 weeks of gestation for counseling between 2013 and 2017 were included. ECV impact factors were analyzed using logistic regression.

Results

A total of 1,598 women presented for breech birth planning. ECV was performed on 353 patients. The overall success rate was 22.4%. A later week of gestation (odds ratio [OR] 1.69), an abundant amniotic fluid index (AFI score) (OR 5.74), fundal (OR 3.78) and anterior (OR 0.39) placental location, and an oblique lie (OR 9.08) were significantly associated with successful ECV in our population. No major complications were observed. The overall vaginal delivery rates could be increased to approximately 14% with ECV.

Conclusion

The demand for alternative birth modes other than CS for breech birth is high in the area of Frankfurt, Germany. Our study offers evidence of the safety of ECV at 38 weeks. Centers with expertise in vaginal breech delivery and ECV can reduce CS-rates. To further establish vaginal breech delivery and ECV as alternate options, the required knowledge and skill should be implemented in the revised curricula.

A Multivariable Predictive Model for Success of External Cephalic Version

OBJECTIVE

To create a prediction model for external cephalic version (ECV) success using objective patient characteristics.

METHODS

This retrospective study included pregnant individuals of at least 18 years of age with a nonanomalous, singleton gestation who underwent an ECV attempt between 2006 and 2016 at a single quaternary care hospital. Variables assessed included maternal age, height, weight, body mass index (BMI), parity, fetal sex, gestational age, estimated fetal weight, type of fetal malpresentation, placental location, and amniotic fluid volume. Univariable and multivariable logistic regression models were used to determine the association of patient characteristics with ECV success. Estimated odds ratios and corresponding 95% CIs were calculated for each variable, and backward elimination and bootstrapping were used to find a parsimonious model for ECV success with the highest discriminatory capacity (as determined by the area under the receiver operating characteristic curve [AUC]). This model was evaluated with a calibration curve across deciles of success.

RESULTS

A total of 1,138 individuals underwent an ECV attempt and were included in this analysis. The overall ECV success frequency was 40.6%. Factors significantly associated with ECV success were maternal age, parity, placental location, estimated fetal weight, and type of fetal malpresentation. A final model with BMI, parity, placental location, and type of fetal malpresentation had the highest AUC (0.667 [95% CI 0.634-0.701]), resulted in good calibration, and is represented by the following equation: 1/[1+e-x] where x=1.1726-0.0314 (BMI)-0.9299 (nulliparity)+1.0218 (transverse or oblique presentation at ECV)-0.5113 (anterior placenta). An interactive version of this equation was created and can be accessed at www.ecvcalculator.com.

CONCLUSION

A prediction model that estimates the probability of ECV success was created and internally validated. This model incorporates easily obtainable and objective patient factors known before ECV and may be used in decision making and patient counseling about ECV.

Patient characteristics associated with complications of external cephalic version

BACKGROUND

Patient characteristics associated with external cephalic version success are well documented; however, the association between patient characteristics and the likelihood of external cephalic version complications is poorly understood.

OBJECTIVE

This study aimed to assess the frequency of patient characteristics associated with complications that lead to unanticipated delivery during external cephalic version.

STUDY DESIGN

This retrospective study included pregnant women aged at least 18 years with singleton gestations who underwent an external cephalic version attempt between 2006 and 2016 at a single quaternary care center. External cephalic version complications were defined as persistent nonreassuring fetal status, placental abruption, labor, spontaneous rupture of membranes, and umbilical cord prolapse. Complications were only considered if they led to unanticipated induction or cesarean delivery within 24 hours of external cephalic version. Patient characteristics including maternal age, height, weight, body mass index, parity, fetal sex, gestational age, estimated fetal weight, the type of fetal malpresentation, and placental location were analyzed for their association with external cephalic version complications using univariable analysis and multivariable logistic regressions.

RESULTS

Among the 1138 patients included in this analysis, external cephalic version complications occurred in 6.7% (n=76). These complications (not mutually exclusive) included nonreassuring fetal status (4.8%, n=55), placental abruption (1.6%, n=18), labor (1.0%, n=11), spontaneous rupture of membranes (0.6%, n=7), and cord prolapse (0.1%, n=1). Neonatal outcomes for those with complications included intensive care unit admission (10.5%, n=8), 5-minute Apgar scores <5 (1.3%, n=1), cord arterial pH <7 (6.6%, n=5), head cooling (1.3%, n=1), and anemia (6.6%, n=5). There were no perinatal deaths. In multivariable analysis, higher body mass index (adjusted odds ratio, 0.90 per kg/m²; 95% confidence interval, 0.84-0.97) and estimated fetal weight (adjusted odds ratio, 0.998 per gram; 95% confidence interval 0.998-0.999) were associated with decreased likelihood of experiencing external cephalic version complications, whereas greater gestational age at procedure (adjusted odds ratio, 1.95 per week; 95% confidence interval, 1.4-2.7) and anterior placental location (adjusted odds ratio, 2.0; 95% confidence interval, 1.1-3.7) were associated with increased likelihood of experiencing external cephalic version complications.

CONCLUSION

In this large series, complications that led to delivery during external cephalic version occurred in 6.7% patients and were associated with body mass index, estimated fetal weight, gestational age, and placental location.

Clinical analysis of 40 cases of external cephalic version without anesthesia

Objective

This study aimed to investigate the success rate, complications, and success-related factors of external cephalic version (ECV) of singleton breech pregnancies after 37 gestational weeks without anesthesia.

Methods

We studied 40 singleton breech pregnancies in women who underwent ECV without anesthesia after 37 gestational weeks from October 2018 to March 2020. On the basis of success of ECV, the women were divided into two groups of the successful group and the failed group. Various factors were analyzed to determine those that affect the success of ECV.

Results

Of the 40 attempts of ECV, 24 (60.0%) were successful and 16 (40.0%) failed. With regard to success-related factors, parity was significantly different between the two groups, with more multiparous women in the successful group than in the failed group. However, none of the other factors were significantly different between the groups. Fetal outcome was good in all of the cases. Ultimately, 3 cesarean sections were performed in the successful group and 16 were performed in the failed group.

Conclusions

ECV of breech presentation after the 37th week of pregnancy without anesthesia is an effective and relatively safe alternative, and can effectively reduce the cesarean section rate.

Association of Persistent Breech Presentation With External Cephalic Version Success

OBJECTIVE

To evaluate a possible correlation between a new variable-persistent breech presentation-and the success rate of external cephalic version (ECV).

METHODS

This was a retrospective study of ECVs performed from January 2008 through January 2019 in an Israeli tertiary care hospital. The study group included all pregnant women who underwent an ECV at or beyond 37 weeks of gestation. Persistent breech presentation was defined as persistent breech presentation during all ultrasound examinations performed between the anatomy scan at mid-pregnancy and the gestational week when ECV was attempted. Women in whom cephalic presentation was documented at least once on these ultrasound examinations were defined as not having persistent breech presentation. The primary outcome was defined as the success rate of ECV, and the secondary outcome was defined as the mode of delivery after a successful ECV.

RESULTS

We identified 1,271 women with breech presentation during the study period. They had undergone median of five (range 2-7) ultrasound examinations. External cephalic version was attempted in 684 women (53.8%), with a success rate of 61.5%. External cephalic version succeeded in 19.6% of those with persistent breech presentation (44/224) compared with 82.0% (377/460) of those without persistent breech presentation (P<.001). Ultimately, women with persistent breech presentation and successful ECV experienced a lower rate of vaginal delivery (27.3% vs 79%, P<.001), and a higher rate of instrumental (29% vs 13%, P<.001) and cesarean deliveries (43% vs 7%, P<.001) compared with the nonpersistent breech presentation group. The rate of noninstrumental vaginal delivery among women with persistent breech presentation, regardless of ECV, was 5.4%.

CONCLUSION

Women with persistent breech presentation experienced a high rate of ECV failure and a low rate of spontaneous vaginal delivery.

External cephalic version - A 10-year review of practice

INTRODUCTION

Following the term breech trial (TBT), the incidence of Caesarean section secondary to breech presentations increased, from 76.9 % to 89.7 %. External Cephalic Version (ECV) is a safe effective method to reduce non-cephalic presentation at time of delivery.

METHODS

Retrospective audit of all the ECV procedures performed at a tertiary women's hospital between Jan 2010 and Jan 2020.

RESULTS

The success rate of ECV was 54.5 %. The rate of vaginal birth following successful ECV was 73.6 % and rate of Caesarean 26.4 %, compared to 96.4 % for those with unsuccessful ECV (P < 0.0001). Factors found to be associated with increased success rates was the use of Intravenous terbutaline (P = 0.03), fetal birth weight ≥3.5 kg (P = 0.0001) and when the procedure is performed by an experienced operator who performed over 20 ECV procedures (P < 0.0001).

CONCLUSION

ECV is a safe and effective procedure to reduce Caesarean section rates secondary to breech presentation. A dedicated ECV clinic with experienced operators and the use of intravenous terbutaline could improve success rate of ECV and reduce the number of Caesareans for breech presentation.

Nitrous oxide analgesia for external cephalic version: A randomized controlled trial

STUDY OBJECTIVE

Our study sought to determine whether or not nitrous oxide analgesia decreases pain compared to oxygen placebo during external cephalic version for breech presentation. Procedural success may be limited by pain and anxiety. Although neuraxial anesthesia has been studied extensively for these procedures, many centers lack resources for routine use. Nitrous oxide is noninvasive, has minimal side effects and requires limited facilities. We hypothesized that its analgesic properties would decrease pain compared to oxygen placebo during external cephalic version.

DESIGN

Double-blinded randomized placebo-controlled trial.

SETTING

Labor and delivery triage room.

PATIENTS

Forty-eight patients, ≥18 years of age, 37-weeks' gestation or beyond, singleton pregnancy, breech presentation, and American Society of Anesthesiology physical status I-III, having an external cephalic version.

INTERVENTIONS

Patients undergoing external cephalic version were randomized to receive self-administered 50% nitrous oxide/50% oxygen versus 100% oxygen placebo.

MEASUREMENTS

The primary outcome measured was intra-procedural pain. Secondary outcomes were intra-procedural anxiety, patient satisfaction, and procedure difficulty.

MAIN RESULTS

Forty-eight patients were enrolled; 23 received nitrous oxide and 25 received oxygen. No difference was noted in mean pain scores (nitrous oxide 5.5 ± 2.3, placebo 5.4 ± 2.7, [CI_95% = -1.40, 1.51]; P = 0.943) or anxiety scores (nitrous oxide 1.6 ± 2.0, placebo 1.2 ± 1.8, [CI_95% = -0.74, 1.45]; P = 0.515). Procedural difficulty (1-10 scale, 1 = very easy, 10 = extremely difficult) was not different between groups (nitrous oxide 6.1 ± 2.2, placebo 6.1 ± 3.2, [CI_95% = -1.54, 1.66]; P = 0.944). There was a significant increase in the number of version attempts in the nitrous oxide group (nitrous oxide 3.9 ± 1.9, placebo 2.8 ± 1.4, [CI_95% = 0.05, 2]; P = 0.046). Patient satisfaction was significantly lower in the nitrous oxide group (nitrous oxide 4.3 ± 4.0, placebo 6.9 ± 3.6, [CI_95% = -4.93, -0.34]; P = 0.025).

CONCLUSION

Despite the desirable properties of nitrous oxide, there was no analgesic benefit over oxygen for external cephalic version. Its routine use for these procedures was not supported.

External cephalic version at term: A 6-year single-operator experience

BACKGROUND

External cephalic version (ECV) should be offered for patients presenting with a noncephalic pregnancy that are willing to deliver vaginally. Various reports have evaluated predictors for successful ECV. Yet, none have reported a single-operator large cohort experience. We aim to analyze the outcome of referrals for ECV.

METHODS

We conducted a retrospective cohort study of prospectively collected data. We performed a multivariate analysis of data with respect to ECV procedures performed by a single operator in a 6-year period. Maternal and fetal characteristics were compared between ECV success and failure groups.

RESULTS

Six hundred and two women underwent ECV. Of them, ECV was successful in 432 (71.7%). A multivariate binary logistic regression model demonstrated that high liquor volume was a predictor of ECV success (Adj OR 1.17 [95% CI 1.09-1.26]). Failure of ECV was correlated with anterior placenta (0.44 [0.56-0.76]) and nulliparity (0.21 [0.11-0.36]). Adverse events were rare and mostly minor, occurring in 1% of procedures.

CONCLUSIONS

ECV has a high success rate and a low complication rate, enabling vaginal birth and avoiding cesarean. The role of manipulation of modifiable determinants such as liquor volume should be further assessed in future studies.

Effectiveness of nitrous oxide in external cephalic version on success rate: A randomized controlled trial

INTRODUCTION

Approximately 4% of singleton pregnancies at term are in breech presentation. External cephalic version (ECV) can reduce the risks of noncephalic birth and cesarean delivery, but this maneuver can be painful. Our aim was to analyze the effect of administering inhaled nitrous oxide for analgesia on the ECV success rate.

MATERIAL AND METHODS

This prospective, randomized, single-blind, controlled trial included women with singleton pregnancies in breech presentation at term who were referred for ECV in a tertiary care center. Women were assigned according to a balanced (1:1) restricted randomization design to inhale either nitrous oxide (N₂ O) in a 50:50 mix with oxygen or medical air during the procedure. The main outcomes reported are the ECV success rate, degree of pain, adverse event rate, and women's satisfaction.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01948115.

RESULTS

The study included 150 women (nitrous oxide group: n = 74; medical air: n = 76). Inhaled nitrous oxide was not associated with a higher ECV success rate than medical air (24.3 vs 19.7%, P = 0.51). Among parous women (n = 34 in each group), the ECV success rate appeared higher in the nitrous oxide group, respectively 47.1% (n = 16) vs 23.5% (n = 8) (P = 0.042). Neither the median pain level nor adverse event rates differed significantly in women with inhaled nitrous oxide compared with medical air.

CONCLUSIONS

Use of an equimolar mixture of oxygen and nitrous oxide during ECV appears safe. Although it does not seem to change the overall success rate, it may increase success in parous women.

Reviving external cephalic version: a review of its efficacy, safety, and technical aspects

Currently, the rate of cesarean sections being performed in Korea is approximately 40%, with Korea ranking 4th among the Organization for Economic Co-operation and Development countries with respect to cesarean deliveries. Breech presentation at term is an important indication for cesarean section among other factors, including medicolegal concerns and pregnancies in women of advanced maternal age. Term breech presentation is associated with a higher fetal mortality rate than that associated with a cephalic presentation. Therefore, in Korea, most of these women deliver by cesarean section to avoid the complications of vaginal breech delivery. However, cesarean section is itself associated with considerable obstetric morbidity and sometimes, mortality. External cephalic version (ECV) is a useful method to reduce the cesarean section rate in women with breech presentation and therefore to reduce the incidence of breech presentation at delivery. Studies have shown that routine use of ECV reduces the cesarean section rate by approximately two-thirds in term pregnancies with breech presentation. ECV is accepted as a safe, efficacious, and cost-effective method and is recommended by both the American College of Obstetricians and Gynecologists and the Royal College of Obstetricians and Gynecologists in all pregnancies with term breech presentation, if not contraindicated. In Korea, although most clinicians are aware of the option of ECV, their relative lack of experience in performing the procedure and fear of complications render them hesitant to perform ECV. This review is aimed at guiding obstetricians by describing the efficacy, safety concerns, and technical aspects of this procedure.

Analysing the likelihood of caesarean birth after implementation of the two-childbirth policy in China, using the Ten Group Classification System

The aim of this study was to identify the main contributor to the high Caesarean section birth rate at a regional perinatal medical centre using the Robson Ten Group Classification System (TGCS). A total of 54,085 women were surveyed and were included in our study from 2015 to 2017 at the Women's Hospital at Zhejiang University School of Medicine in Hangzhou, China. The Caesarean birth rate was similar among the three years; although, the new two-childbirth policy in China has been in implementation since 2016. According to the TGCS, Group 5 was the largest contributor to the overall Caesarean birth rate (40.79%), followed by Group 2 (21.36%). The Caesarean birth rate of Group 5 and Group 2 decreased significantly from 2015 to 2017 (p < .05). The proportion of Group 7 contributing to the overall Caesarean birth rate increased significantly (p < .05). Future efforts should focus on increasing vaginal birth after Caesarean in Group 5 and external cephalic version in Group 7 to decrease the overall Caesarean birth rate.Impact statementWhat is already known on this subject? The Ten Group Classification System (TGCS) proposed by World Health Organisation was used in some countries such as Queensland, Singapore and Japan to assess and compare Caesarean section rates. The main contributor to the high Caesarean birth rate varies in different counties. However, it is not widely used in China.What the results of this study add? It was the first study using the TGCS to analyse the Caesarean birth rate and the changes after implementation of the two-childbirth policy in China. It identified that Group 5 (multiparous mothers with a previous Caesarean birth in a singleton, cephalic full-term pregnancy) constituted the most important determinant of overall Caesarean birth rates, followed by Group 2 (nulliparous mothers with a singleton, cephalic full-term pregnancy undergoing an induction of labour or prelabour Caesarean birth). The contribution of Group 5 and Group 7 (multiparous women with a single breech pregnancy) to the overall Caesarean birth rate has increased significantly since the new childbirth policy was implemented.What the implications are of these findings for clinical practice and/or further research? Future efforts should focus on increasing vaginal birth after Caesarean in Group 5 and external cephalic version in Group 7 to decrease the overall Caesarean birth rate in China.

Introduction of a dedicated team increases the success rate of external cephalic version: A prospective cohort study

OBJECTIVE

To investigate the influence of a dedicated team on the success rate of external cephalic version and mode of delivery.

STUDY DESIGN

This prospective cohort study included 673 women with a singleton fetus in breech presentation who underwent external cephalic version between January 2013 and December 2017 at Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands. In January 2014, a dedicated team consisting of six gynaecologists and six midwives was introduced at the study clinic. The success rate of external cephalic version and mode of delivery were analysed. In addition, predictors for success were examined by logistic regression analysis. Successful external cephalic version was defined as fetal cephalic presentation immediately following the procedure.

RESULTS

Following the introduction of a dedicated team in 2014, the success rate of external cephalic version increased from 39.8% in 2013 to 69.5% in 2017 (p < 0.001), with the greatest increase in nulliparous women (from 23.5% to 58.5%, p = 0.002). Over the 5-year study period, the vaginal delivery rate after external cephalic version increased from 43% in 2013 to 71% in 2017 (p < 0.05). The rate of caesarean section after external cephalic version decreased from 55% to 27% (p < 0.05). Anterior placenta [odds ratio (OR) 0.7, 95% confidence interval (CI) 0.48‒0.97] and complete breech (OR 0.2, 95% CI 0.07‒0.90) were significantly associated with a lower success rate.

CONCLUSIONS

This study showed that introduction of a dedicated team led to a significant increase in the success rate of external cephalic version, and a significant decrease in the rate of caesarean section for women presenting with breech in pregnancy.

Predictors of a successful external cephalic version: A population-based study of Washington state births

BACKGROUND

Breech presentation affects approximately 3% of women with singleton pregnancies. External cephalic version is a manual procedure that reorients a foetus to cephalic position in preparation for birth, reducing indications for caesarean birth. However, unsuccessful attempts are associated with some adverse health outcomes. Versions are successful in 17-86% of attempts. Temporal trends in version success and association between maternal height or prenatal care and version success are unknown. Few population-based studies and no recent investigations in the United States have evaluated predictive factors for version success.

OBJECTIVES

This study aimed to estimate the proportion of successful version procedures in the United States and to evaluate factors associated with version success.

METHODS

We used birth certificate and hospital administrative data. The study included all women who had a singleton birth in Washington State between 2003-2014 following a version procedure (total n=4981). Prevalence ratios and 95% confidence intervals were calculated using Poisson regression.

FINDINGS

57.2% of version attempts were successful. Primiparity (Prevalence Ratio:1.43; 95% Confidence Interval:1.29-1.60) and multiparity (Prevalence Ratio:1.68; 95% Confidence Interval:1.50-1.88) were associated with procedure success. Oligohydramnios was associated with lower version success (Prevalence Ratio:0.75; 95% Confidence Interval:0.57-1.00). Maternal height, pre-pregnancy weight, polyhydramnios, frequency of prenatal care, smoking, infant sex, and year of birth were not significantly associated with version outcome.

CONCLUSION

We found that most version procedures are successful. This reinforces that procedures may be able to reduce the frequency of caesarean birth. These contemporary results can help women and clinicians make decisions with realistic estimates of success.

Applying the Newman-Peacock Prognostic System to a Portuguese Obstetrical Population - A Useful Tool?

BACKGROUND

 External cephalic version (ECV) is a maneuver that enables the rotation of the non-cephalic fetus to a cephalic presentation. The Newman-Peacock (NP) index, which was proposed by Newman et al. in a study published in 1993, was described as a prediction tool of the success of this procedure; it was validated in a North-American population, and three prognostic groups were identified.

PURPOSE

 To evaluate the value of the NP score for the prediction of a successful ECV in a Portuguese obstetrical population, and to evaluate maternal and fetal safety.

METHODS

 We present an observational study conducted from 1997-2016 with pregnant women at 36-38 weeks of pregnancy who were candidates for external cephalic version in our department. Demographic and obstetrical data were collected, including the parameters included in the NP index (parity, cervical dilatation, estimated fetal weight, placental location and fetal station). The calculation of the NP score was performed, and the percentages of success were compared among the three prognostic groups and with the original study by Newman et al. The performance of the score was determined using the Student t-test, the Chi-squared test, and a receiver operating characteristic (ROC) curve.

RESULTS

 In total, 337 women were included. The overall success rate was of 43.6%. The univariate analysis revealed that multiparity, posterior placentation and a less engaged fetus were factors that favored a successful maneuver (p < 0.05). Moreover, a higher amniotic fluid index was also a relevant predictive factor (p < 0.05). The Newman-Peacock score had a poorer performance in our population compared with that of the sample of the original study, but we still found a positive relationship between higher scores and higher prediction of success (p < 0.001). No fetal or maternal morbidities were registered.

CONCLUSIONS

 The Newman-Peacock score had a poorer performance among our population compared to its performance in the original study, but the results suggest that this score is still a useful tool to guide our clinical practice and counsel the candidate regarding ECV.