External Cephalic Version PDF

External cephalic version Official reprint from UpToDate® www.uptodate.com ©2024 UpToDate® External cephalic version Author: G Justus Hofmeyr, MD Section Editor: Charles J Lockwood, MD, MHCM Deputy Editor: Alana Chakrabarti, MD...

External cephalic version Official reprint from UpToDate® www.uptodate.com ©2024 UpToDate® External cephalic version Author: G Justus Hofmeyr, MD Section Editor: Charles J Lockwood, MD, MHCM Deputy Editor: Alana Chakrabarti, MD Contributor Disclosures All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Nov 2024. | This topic last updated: Oct 26, 2023. INTRODUCTION External cephalic version (ECV) refers to a procedure in which the fetus is rotated from a noncephalic to a cephalic presentation by manipulation through the mother's abdomen ( figure 1). It is typically performed as an elective procedure in nonlaboring patients at or near term to improve their chances of having a vaginal cephalic birth. The success of ECV is influenced by both maternal and fetal factors. This topic will discuss the procedure for ECV. The causes, diagnosis, management, and outcome of breech presentation are - Page 1 of 63 - External cephalic version reviewed separately. (See "Overview of breech presentation".) OUTCOMES Outcomes of ECV include the ability to turn a fetus from breech to cephalic presentation (ie, success rate), and the proportion of fetuses that remain in cephalic presentation at birth which affects the frequency of cesarean birth. Version to cephalic presentation — Success rates of ECV vary widely, ranging from as low as 22 percent to as high as 76 percent [1-5]. In a meta-analysis of 84 studies including almost 13,000 version attempts at term, the pooled success rate was 58 percent. After successful ECV, reversion to breech presentation occurs in a small subset of patients. For example, in one study of 2614 ECV attempts, 2.2 percent of successfully verted cases reverted to breech. In addition, a small subset of patients with unsuccessful ECV have spontaneous version to a cephalic presentation. In the same study, 4.3 percent of patients with an unsuccessful ECV attempt subsequently had spontaneous cephalic version. The success of ECV is influenced by both maternal and fetal factors, as discussed in the following sections. - Page 2 of 63 - External cephalic version Factors that impede success — Factors that may be associated with lower ECV success rates include: Anterior [4,6-10], lateral , or cornual placenta. Decreased amniotic fluid volume [8-10,12-14]. Descent of the breech into the pelvis [9,13,15,16]. Female sex. Fetal head not palpable [9,15]. Firm maternal abdominal muscles. Frank breech presentation [8,18]. Low birth weight [5,10,12]. Nulliparity [4-9,12,15,19-21]. In the series including 2614 ECV attempts discussed above (see 'Version to cephalic presentation' above), nulliparous compared with parous patients had lower rates of ECV success (40 versus 64 percent). Obesity [5,8,13,15,22]. In one large series, patients with a body mass index (BMI ≥40 kg/m2) compared with normal BMI had a lower ECV success rate (59 versus 65 percent); of those patients, vaginal birth rates were also lower (60 versus 81 percent). However, one large study found no effect. Persistent breech presentation (ie, breech presentation - Page 3 of 63 - External cephalic version confirmed during every ultrasound examination from midpregnancy onward). Posteriorly located fetal spine [13,18]. Tense uterus. Thinner myometrial thickness. Some of these factors may also impede spontaneous version. Factors that enhance success — In addition to absence of the above unfavorable prognostic factors, favorable prognostic factors may include [27-30]: Amniotic fluid index >10 cm. Complete breech position. Nonlongitudinal lie – A fetus in oblique or transverse lie is easier to rotate to a cephalic lie than the breech fetus since only small degrees of rotation are needed and these lies are inherently unstable. Posterior placental location. Provider experienced in ECV and/or use of a standard ECV protocol – In one cohort study, introduction of a dedicated ECV team increased the overall success rate from 40 to 70 percent; lower rates were reported in nulliparous patients (24 to 59 percent). Similarly, in another cohort study, - Page 4 of 63 - External cephalic version implementation of a standardized protocol for ECV was associated with an increase in the success rate (47 percent [110/236 pregnant patients] to 61 percent [85/139 pregnant patients]). Unengaged presenting part – In one retrospective study, sonographic measurement of the forebag (ie, distance from the internal cervical os to the presenting part) was an objective method for interpreting the degree of engagement and was predictive of ECV success. In this study, a forebag >1 cm was highly predictive of successful ECV, whereas a forebag 180,000 participants with breech fetuses, patients undergoing attempted ECV had a lower risk of cesarean birth compared with - Page 7 of 63 - External cephalic version those who did not undergo attempted ECV (43 versus 75 percent; relative risk [RR] 0.57, 95% CI 0.5-0.64). A separate meta- analysis of eight randomized trials including 1308 patients reported similar findings (risk ratio [RR] 0.57, 95% CI 0.40-0.82). In another study that included 2614 ECV attempts, the cesarean birth rate was 55 percent (16 percent among those with successful ECV and 93 percent among those with unsuccessful ECV). It should be noted that there is considerable variability in cesarean birth rates in different settings depending on local practices of allowing vaginal breech birth. For example, cesarean birth rates are higher in studies performed in the United States and other countries where vaginal breech birth is uncommon (eg, Europe, Canada, Australia, New Zealand) and lower in countries where vaginal breech is more common (eg, India, Sudan, Zimbabwe, South Africa) [44,45]. However, the cesarean birth rate after successful ECV remains higher than in the general obstetric population. In a meta-analysis of observational studies evaluating mode of birth, patients with a successful ECV compared with a cephalic-presenting fetus and no ECV had an approximately two-fold higher rate of cesarean birth (21 versus 11 percent, RR 2.19, 95% CI 1.73-2.76). The excess risk of cesarean birth was due to both dystocia and nonreassuring fetal heart rate patterns. There is no clear explanation for the - Page 8 of 63 - External cephalic version increased frequency of dystocia after successful ECV. One theory is that factors common to both breech presentation and successful ECV, such as an unengaged presenting part or small maternal pelvis, are also risk factors for dystocia. Parity also plays a role in risk of dystocia. Multiparous patients are more likely than nulliparas to give birth vaginally after successful ECV [47,48]. By contrast, rates of cesarean birth appear to be similar for those with a fetus in cephalic presentation after ECV compared with spontaneous version. In a secondary analysis of a randomized trial, patients with a cephalic-presenting fetuses at birth as a result of successful ECV versus cephalic presenting fetuses who spontaneously turned from breech presentation in the third trimester had similar rates of cesarean birth. ECV has also been reported to be cost-effective in studies from the United States and United Kingdom [50,51]. In one such study, ECV was cost-effective when compared with a scheduled cesarean birth for breech presentation when the probability of successful ECV was greater than 32 percent. RISKS Risks associated with ECV are infrequent but include stillbirth, abruption, and emergency cesarean birth. - Page 9 of 63 - External cephalic version These risks must be weighed against the risks associated with: Persistent breech presentation, including cord prolapse, probable cesarean birth, and complications of breech birth (whether vaginal or cesarean). Planned cesarean birth, including: Precipitous labor leading to unplanned vaginal breech birth. Maternal risks (eg, surgical site infection, surgical injury, hemorrhage). Fetal/neonatal risks (eg, laceration during hysterotomy, transient tachypnea of the newborn, admission to high care unit, immune sequelae probably related to microbiome disturbance due to lack of exposure to vaginal flora ). An increased risk for development of childhood medical illnesses (eg, asthma, laryngitis, gastroenteritis, ulcerative colitis, celiac disease, lower respiratory tract infection, juvenile idiopathic arthritis) and reduced brain maturation have also been described [53- 55]. (See "Cesarean birth: Postoperative care, complications, and long-term sequelae".) Risks of ECV were reported in a systematic review of 84 observation studies and randomized trials including 12,955 - Page 10 of 63 - External cephalic version patients undergoing ECV after 36 weeks and included the following : Overall complications – The pooled overall complication rate was 6.1 percent (95% CI 4.7-7.8) and included abnormal fetal heart rate changes, fetomaternal transfusion, vaginal bleeding, emergency cesarean birth, rupture of membranes, stillbirth, abruption, and cord prolapse. The overall complication rate is comparable to that of other large series [56,57]. Stillbirth – The pooled risk of fetal death was 0.19 percent (95% CI 0.12-0.27), or 1 in 5000 ECV attempts. Only 2 of the 12 deaths were attributed to ECV; the remainder were unrelated or unexplained. In a subsequent systematic review of randomized trials, perinatal death occurred in 2 of 644 infants in the attempted ECV group and 6 of 661 infants in the group of breeches that did not undergo ECV (relative risk [RR] of perinatal death 0.39, 95% CI 0.09-1.64). The corrected perinatal mortality in a cohort of 2614 ECV attempts was 0.12 percent. Abruption – The pooled risk of abruption was 0.18 percent (95% CI 0.12-0.26), or 1 in 1200 ECV attempts. Emergency cesarean birth – Emergency cesarean birth was - Page 11 of 63 - External cephalic version performed in 49 cases; the pooled risk of emergency cesarean birth was 0.35 percent (95% CI 0.26-0.47), or 1 in 286 ECV attempts. There was no definite correlation between the risk of complications and whether or not the ECV was successful. There were also several limitations to this analysis. For example, there were differences among studies in design, patient populations, ECV techniques, and ascertainment/definition of outcomes. Since many studies did not determine relevant outcomes among patients with breech presentation who did not undergo ECV, a reliable comparison of the risk of ECV versus expectant management could not be performed. In addition, there was no assessment of maternal satisfaction, including degree of discomfort and, possibly, negative psychological effects in the event of failure [1,58-60]. CANDIDATES Patients with confirmed breech — ECV is offered to most patients with a noncephalic fetal lie. While the factors noted above may affect the success rate, it can be very difficult to predict success or failure in an individual case. Thus, it is reasonable to offer ECV to patients without contraindications. (See 'Factors that - Page 12 of 63 - External cephalic version impede success' above and 'Factors that enhance success' above and 'Potential contraindications' below.) Patients most likely to opt for ECV are those who are well- informed, encouraged to undergo the procedure, believe in its safety, and desire a vaginal birth. Patients may choose not to undergo ECV because of fear of the procedure, incomplete information, and preference for planned cesarean birth. Detection of breech presentation on physical examination, however, is imperfect and ultrasound examination improves detection of breech presentation. In one prospective study, 54 percent of breech presentations were unsuspected on clinical examination prior to ultrasound examination at 36 weeks gestation. In another cohort study, introduction of routine ultrasound examination at 36 weeks reduced the rate of undiagnosed breech before labor from 22.3 to 4.7 percent (relative risk 0.21, 95% CI 0.12-0.36). Potential contraindications Absolute contraindications – Any absolute contraindication to labor and vaginal birth, regardless of fetal presentation, is an absolute contraindication to ECV; examples include placenta previa and previous classical cesarean birth. Relative contraindications – There is no consensus about - Page 13 of 63 - External cephalic version other contraindications to ECV and no strong evidence on which to base recommendations. Based primarily on expert opinion, ECV is generally contraindicated in the following settings because they are associated with a low likelihood of successful version and/or increased risk of fetal harm from the procedure: Fetal growth restriction Hyperextended fetal head Multiple gestation – In a systematic review including 23 cases of attempted ECV for a noncephalic-presenting twin, the ECV success rate was 57 percent and the vaginal birth rate was 48 percent. In a subsequent prospective study including twin gestations, ECV of twin A was successful in 10/18 (56 percent) of cases. Additional randomized trials are needed to assess the safety and efficacy of ECV for the presenting twin. Acceptable approaches for the management of a second twin in breech presentation include ECV and breech extraction; breech extraction compared with ECV may be associated with a higher successful vaginal birth rate. (See "Twin pregnancy: Labor and delivery", section on 'Cephalic/noncephalic presentation'.) - Page 14 of 63 - External cephalic version Nonreassuring fetal monitoring test results Placental abruption Previous vertical lower uterine segment cesarean birth Ruptured membranes Severe oligohydramnios Significant fetal or uterine anomaly (eg, hydrocephaly, septate uterus). TIMING For most patients with breech fetuses who have no contraindications to the procedure, we offer ECV any time after 36 0/7 weeks of gestation but typically perform the procedure at 37 weeks of gestation. This approach takes advantage of the higher probability of turning the fetus before term, that the fetus will remain cephalic, and that the fetus is mature or nearly mature in the event of complications necessitating urgent cesarean birth [68,69]. Our approach is consistent with expert guidelines: The American College of Obstetricians and Gynecologists (ACOG) recommends discussing ECV at ≥36 0/7 weeks and performing the procedure at ≥37 0/7 weeks ; the Royal College of Obstetricians and Gynaecologists (RCOG) recommends offering ECV from 37 0/7 - Page 15 of 63 - External cephalic version weeks, but states ECV may be offered to nulliparas at 36 0/7 weeks. ECV at earlier gestations (eg, 34 0/7 to 35 6/7 weeks) has a higher success rate than term ECV, but this advantage needs to be weighed against the possibility of delivering a preterm infant (due to an ECV-related complication) and lack of convincing evidence of a substantial reduction in cesarean birth with early versus term ECV. ECV at later gestations (eg, 39 0/7) may be performed for patients with a fetus in a nonlongitudinal lie (ie, transverse, oblique). (See 'Nonlongitudinal lies' below.) In a meta-analysis of three trials including 1906 participants, early compared with term ECV reduced the rate of noncephalic presentation at birth (42 versus 52 percent; risk ratio [RR] 0.81, 95% CI 0.74-0.9). While the cesarean birth rate was also lower in the early ECV group, the difference was modest and had borderline statistical significance (52 versus 56 percent; RR 0.92, 95% CI 0.85-1). Reasons for the lack of a clear impact on the cesarean birth rate include the possibility that fetuses in noncephalic presentation in the third trimester have characteristics that place them at higher risk of having antepartum/intrapartum complications necessitating cesarean - Page 16 of 63 - External cephalic version birth even if they turn or are turned to cephalic presentation, and a willingness among European hospitals to deliver the term, but not preterm, breech fetus vaginally. The largest trial in the meta-analysis included over 1500 patients with singleton breech fetuses who were randomly assigned to early (34 0/7 to 35 6/7 weeks) or term (≥37 weeks) ECV. Nearly all procedures were performed by experienced practitioners; repeated ECV attempts were permitted, as was use of tocolytics and neuraxial anesthesia. Patients in the early ECV group had a lower risk of noncephalic fetal presentation at birth (41 versus 49 percent, relative risk [RR] 0.84, 95% CI 0.75-0.94). The procedure was also slightly less painful at earlier gestations, but the difference was probably not clinically significant. Rates of cesarean birth between groups were similar (52 versus 56; RR 0.93, 95% CI 0.85-1.02). Rates of preterm birth before 37 weeks and median gestational age at birth (39.1 weeks) were also similar between groups. Complications during the procedure occurred in 3 to 4 percent of patients in each group; the most common complication was a nonreassuring fetal heart rate tracing. ALTERNATIVES Alternatives to ECV include expectant management, postural - Page 17 of 63 - External cephalic version maneuvers to facilitate spontaneous version, moxibustion, and acupuncture. Expectant management — Options for expectant management include planned cesarean birth (scheduled or unscheduled) of a persistently breech fetus or a trial of labor of a persistently breech fetus. (See "Overview of breech presentation", section on 'Approach to management at or near term (singleton pregnancies)'.) Since spontaneous version may occur at any time, even after a failed ECV, a case can be made for delaying cesarean birth for breech presentation until late pregnancy or early labor. Risks associated with delaying cesarean birth include potential complications of persistent breech presentation (eg, cord prolapse, precipitous labor if membranes rupture) and increased risk of maternal infection when cesarean birth is performed intrapartum versus prepartum. There are insufficient data to balance the potential benefits and risks of expectant management, but risks are probably low for most patients. Postural maneuvers to facilitate spontaneous version — There are insufficient data to recommend for or against the use of postural maneuvers (eg, pelvic elevation using a knee-chest - Page 18 of 63 - External cephalic version position with or without a full bladder [73,74], supine head-down position with the pelvis supported by a wedge-shaped cushion , lateral position on the side opposite the fetal back ) for version of the nonvertex fetus, but these maneuvers are unlikely to be harmful. By contrast, home-based rebozo exercises appear to have a negative effect and may decrease the rate of cephalic presentation at birth. High quality evidence that maternal postural changes facilitate spontaneous version are lacking. In a systematic review of six randomized and quasi-randomized trials including 417 patients, maternal postural management compared with no intervention resulted in a similar rate of noncephalic births. Moxibustion and acupuncture — There are insufficient data to recommend for or against the use of Moxibustion, a Chinese herb, that when burnt close to the skin of the tip of the fifth toe (acupuncture point Bladder 67 [BL67], Chinese name Zhiyin), has been proposed as a means of correcting breech presentation. It can be used alone or with acupuncture. The procedure is performed for 20 to 60 minutes, once or twice per day, two to seven times per week for one to two weeks. In a systematic review of randomized and quasi-randomized trials including subjects with a singleton breech fetus, moxibustion - Page 19 of 63 - External cephalic version compared with no moxibustion resulted in lower rates of noncephalic presentation at birth (risk ratio [RR] 0.87, 95% CI 0.78 to 0.99; seven trials, 1152 patients). However, rates of cesarean birth were similar between groups (six trials, 1030 subjects). Adverse events may include abdominal pain, nausea, an unpleasant odor which can cause respiratory irritation, and burns. PREPROCEDURE Ultrasound examination — Prior to performing ECV, an ultrasound examination is performed to confirm fetal and placental position (placenta previa is a contraindication to vaginal birth) and to look for factors which can reduce the likelihood of success (eg, oligohydramnios, significant fetal or uterine anomalies) which may warrant not proceeding with ECV. (See 'Factors that impede success' above and 'Potential contraindications' above.) Assessment of fetal well-being — Fetal well-being is documented with a reactive fetal heart rate pattern or satisfactory biophysical profile score before exposing the fetus to a potentially stressful procedure. In low-resource settings without access to ultrasound or fetal heart rate monitoring, fetal well-being may be confirmed based on a report of good fetal movements or a positive clinical - Page 20 of 63 - External cephalic version fetal acoustic stimulation test and probably outweighs the risks of no ECV attempt. Counseling — Patients are informed of the relative advantages and disadvantages of ECV in order to make an informed decision. This choice is likely to be influenced by the value the patient places on a vaginal cephalic birth. In addition to a description of the procedure, some of the elements of informed consent include a discussion of: Why the procedure is being performed (if ECV is successful, the patient is likely to avoid cesarean birth performed because of breech presentation). Alternatives to ECV. (See 'Alternatives' above.) Overall success rate; all patients should be informed of the possibility of failure, whether or not risk factors for failure are present. (See 'Outcomes' above and 'Factors that impede success' above.) The small chance that the fetus will spontaneously revert to breech. (See 'Version to cephalic presentation' above.) Risks. (See 'Risks' above.) Procedure-related discomfort. Side effects of any medications that may be administered. - Page 21 of 63 - External cephalic version Management plans if the procedure is successful or unsuccessful (eg, amniotomy and induction, scheduled cesarean birth, second attempt at ECV). Counseling is more effective and patient satisfaction is higher if a structured decision aid for patients with breech presentation is used [80,81]. Oral intake — Given the low complication rate, we and others believe intravenous (IV) access and avoidance of oral intake before the procedure are unnecessary. In fact, we actually encourage increased oral fluid intake for 24 hours prior to ECV attempt as this may increase amniotic fluid volume, though not proven to increase ECV success rate. (See 'Other' below.) However, some practice guidelines recommend a two-hour oral restriction , and other providers place an IV catheter and restrict oral intake for four to 8 hours before the procedure in case emergency cesarean birth becomes necessary. PROCEDURE The procedure should be performed by an experienced operator in a facility with ready access to emergency cesarean birth. A video of the author performing an ECV can be found here ( - Page 22 of 63 - External cephalic version movie 1). Video recordings of the ECV technique have also been published in the WHO Reproductive Health Library and in the Journal of Visualized Experiments (JoVE). A video recording of a two- operator technique is available online. Simulation training models have been developed [88,89], and various modifications of the technique have been reported. Technique — Various techniques have been reported but have not been compared in randomized trials. Our technique is described here and in the algorithm ( algorithm 1): Each step of the procedure is explained to the patient. The patient is positioned on a narrow, firm examination table with the fetal back towards the operator. A wedge or cushion can be used to tilt the uterus towards the operator and minimize aortocaval compression. Tocolysis is administered in most patients. (See 'Tocolysis' below.) Patients are asked to keep their abdominal muscles relaxed and inform the operator if they feel any discomfort, rather than tensing their abdominal muscles, so that the pressure being used can be modified. Good rapport with patients is essential to help them relax and keep them from tensing - Page 23 of 63 - External cephalic version their muscles, which makes it more difficult to manipulate the fetus. Ultrasound coupling gel or powder (eg, cornstarch) is applied to the patient's abdomen to help the operator's hands slide over the skin while manipulating the fetus. Ultrasound coupling gel is typically used when the fetal heart rate is monitored by ultrasound rather than by intermittent auscultation. In a randomized trial, aqueous gel was more effective than powder for reducing maternal pain. The breech is disengaged from the pelvis by slowly inserting the fingertips of both hands deeply behind the symphysis pubis to scoop the breech from the pelvis to a position above the sacral promontory. Some obstetricians prefer to use two operators, one manipulating the breech and the other the fetal head. The author prefers to begin with a backward somersault, whereas ACOG describes beginning with a forward roll and then attempting a backward roll if the forward roll fails. Backward somersault – For the fetus in the left sacrolateral position with planned backward somersault ( figure 2), the operator stands on the patient's left side, on the same side as the fetal back. After disengagement - Page 24 of 63 - External cephalic version from the pelvis as described above, the breech is held with the edge of the left palm and pushed toward the patient's right flank and upward. If the patient is steeply tilted on their side against a wall, the operator may sit and steady their left elbow on the examination table during the rest of the procedure. If version is not completed by this maneuver, the head is gently manipulated towards the patient's left flank and downward with the edge of the right hand, taking care to apply most pressure to the breech so that a flexed posture is maintained. Slight back-and-forth movement between the two hands may help promote fetal movement, but generally, pressure on the fetus should be slow and steady rather than repeated pushing. For the fetus in the right sacrolateral position, the operator stands on the patient's right side and uses the right to hand to elevate the breech towards the patient's left flank. Forward somersault – For the fetus in the left sacrolateral position with planned forward somersault ( figure 1), the operator is positioned on the right side of the patient, on the opposite side as the fetal back. The - Page 25 of 63 - External cephalic version procedure is similar to that described above, except that once the breech has been disengaged from the pelvis, more pressure is applied to the head than the breech, to maintain flexion of the baby. The fetal heart rate is auscultated every two minutes, with interruption of the procedure if bradycardia occurs. In one large series, an abnormal fetal heart rate leading to discontinuation of the ECV occurred in approximately 5 percent of cases. If ECV is unsuccessful after five minutes of attempts, we stop and let patients rest on their side for approximately two minutes before making another attempt, if they agree to it. We avoid making more than four attempts at one sitting. Role of ancillary measures to enhance success — Several ancillary measures have been evaluated to look for ways to improve the success rate of ECV. The rationale for most of these interventions is to relax the uterus and/or anterior abdominal wall musculature and thereby enhance the operator's ability to manipulate the fetus. Tocolysis — For most patients, tocolysis is used prior to ECV; tocolysis appears to be the most studied and effective ancillary measure to relax the uterus and improve ECV success rates. Use of - Page 26 of 63 - External cephalic version tocolysis may also increase the success of repeat ECV in patients who have undergone a previous unsuccessful attempt. This approach is consistent with expert guidelines [39,70,95]. However, for patients in whom clinical assessment suggests that ECV is likely to be achieved easily, an initial attempt without tocolysis may be made. In our experience, this accounts for fewer than 20 percent of cases. Favorable clinical features include multiparity, easily palpable fetal parts, mobility of the fetus on palpation, and an unengaged presenting breech. (See 'Factors that enhance success' above.) Beta-adrenergic agonists — When tocolysis is used, beta- adrenergic agonists are the preferred agent. One simple regimen is terbutaline 0.25 mg subcutaneously 15 to 30 minutes prior to the procedure. Alternatively, salbutamol 0.1 mg in 20 mL saline can be administered slowly intravenously (IV) immediately prior to the procedure; maternal heart rate is monitored during use. In a systematic review of six randomized trials, ECV performed with versus without tocolysis with a parenteral beta-adrenergic agonist was associated with an increased prevalence of cephalic presentation in labor (average risk ratio [RR] 1.68, 95% CI 1.14- 2.48) and a reduction in cesarean birth rates (average RR 0.77, 95% CI 0.67-0.88) in both nulliparous and multiparous patients. - Page 27 of 63 - External cephalic version Other tocolytics — Information on other tocolytics (eg, atosiban [not available in the United States], nitroglycerin, nifedipine) are limited but suggest these agents are less effective than beta-adrenergic agonists. Atosiban – In a randomized trial including over 800 patients undergoing ECV, those treated with atosiban compared with fenoterol (a beta-adrenergic agonist not available in the United States) had lower rates of successful ECV (34 versus 40 percent, RR 0.73, 95% CI 0.55-0.93); rates of cephalic presentation at birth were similar between groups. While the rate of cesarean birth was also similar, it trended higher in the atosiban group (60 versus 55 percent, RR 1.09, 95% CI 0.96-1.2). Nitroglycerin – IV nitroglycerin [98,99], or sublingual nitroglycerin spray [100-102], has also been evaluated for tocolysis. In a systematic review of randomized trials evaluating the use of nitroglycerin in pregnancy, nitroglycerine compared with placebo had similar effects on relaxing the uterus prior to ECV. However, in a subsequent placebo-controlled trial, use of IV nitroglycerin appeared to increase ECV success in nulliparous, but not multiparous, patients. - Page 28 of 63 - External cephalic version Nitroglycerin has also been compared with beta-adrenergic agonists and appears to be less effective and associated with more side effects. In a randomized trial including 74 patients undergoing ECV, sublingual nitroglycerin (0.8 mg) compared with IV ritodrine (111 mcg/min) was associated with more side effects (eg, headache, fall in blood pressure) and fewer successful versions (25 versus 45 percent), although this was not statistically significant. A retrospective study also reported that nitroglycerin was less effective than terbutaline for patients undergoing ECV with neuraxial anesthesia. Nifedipine – In a systematic review including two trials evaluating tocolysis before ECV, nifedipine compared with terbutaline or placebo did not increase the rate of successful version or lower the rate of cesarean birth. Role of neuraxial anesthesia — For most patients undergoing ECV, we do not use neuraxial anesthesia. While neuraxial anesthesia may be effective, it is invasive, can be costly , and most patients experience only mild discomfort. Helping the patient relax and reducing abdominal pressure may help reduce this discomfort. However, neuraxial anesthesia in combination with tocolysis is a reasonable option when ECV with tocolysis alone is unsuccessful, or at the time of planned cesarean birth when neuraxial anesthesia can be used for delivery (cesarean - Page 29 of 63 - External cephalic version or vaginal). Neuraxial anesthesia, in combination with tocolysis, can further increase ECV success rates. In a meta-analysis of nine randomized trials including 934 patients undergoing ECV with tocolysis, use of neuraxial anesthesia versus IV or no analgesia : Increased the ECV success rate by 44 percent (58.4 versus 43.1 percent, RR 1.44, 95% CI 1.27-1.64) Increased the rate of cephalic presentation in labor by 37 percent (55.1 versus 40.2 percent, RR 1.37, 95% CI 1.08-1.73) Increased the vaginal birth rate by 21 percent (54 versus 44.6 percent, RR 1.21, 95% CI 1.04-1.41) Reduced the cesarean birth rate by 17 percent (46 versus 55.3 percent, RR 0.83, 95% CI 0.71-0.97) Although a theoretic risk of neuraxial anesthesia is that abolishing the mother's sensation may allow excessive use of force and thus increase the risk of complications, complication rates were similar in both groups. The cost of neuraxial anesthesia for ECV may be offset by the reduced rate of cesarean birth after successful version. Other — Other ancillary measures (eg, vibroacoustic stimulation, amnioinfusion, hydration, analgesia) have been proposed but data - Page 30 of 63 - External cephalic version are limited. Vibroacoustic stimulation – Fetal vibroacoustic stimulation may improve ECV rates, but data are limited. Fetal vibroacoustic stimulation is used to stimulate a fetus in midline spine position to shift to a spine lateral position, which facilitates manipulating the fetus into a forward or backward roll. It is a reasonable ancillary measure as it is inexpensive, well-tolerated, and probably harmless; however, more data are needed to prove the efficacy of this approach. In one small crossover trial, patients exposed to fetal vibroacoustic stimulation compared with unexposed patients had higher rates of successful ECV (19 of 22 versus 1 of 12 patients); the rate of failed ECV was reduced with this intervention (RR 0.17, 95% CI 0.05-0.6). Amnioinfusion – Amnioinfusion does not appear to improve ECV success rates. Two small uncontrolled studies of amnioinfusion before ECV reported discordant results. In one study, six patients with failed ECV had a successful repeat attempt following transabdominal amnioinfusion with 700 to 900 mL warmed saline. By contrast, in a subsequent study, none of seven cases were successful. A randomized trial was stopped early because of recruitment - Page 31 of 63 - External cephalic version difficulties but did not report a higher rate of cephalic presentation at birth when amnioinfusion was performed before a second attempt at ECV. (See "Amnioinfusion", section on 'Transabdominal approach'.) Hydration – Preprocedure hydration does not appear to improve ECV success rates. In a prospective study, maternal IV infusion with 2 L of hypotonic saline over two hours before ECV compared with no IV hydration increased amniotic fluid volume but did not result in higher ECV success rates. Similarly, in a randomized trial, oral hydration with 2 L of water two hours before ECV compared with patients who did not receive the intervention increased amniotic fluid volume but did not result in a higher ECV success. Analgesia Nitrous oxide – Nitrous oxide does not appear to improve ECV success rates. In a cohort study, inhalation of nitrous oxide (50 percent; 300 patients) compared with no analgesic reduced the proportion of patients who experienced severe pain during ECV, but did not affect other outcomes (eg, ECV success rate, rate of cesarean birth). Similarly, a small randomized trial and a meta-analysis found no benefit of inhaled nitrous - Page 32 of 63 - External cephalic version oxide compared with oxygen placebo. Remifentanil – While remifentanil, an opioid, appears to improve rates of ECV (but not rates of cesarean birth), we do not use opioid analgesia for ECV in our practice. In a meta-analysis of four randomized trials including 482 patients undergoing ECV, remifentanil compared with placebo or no anesthesia increased ECV success rates (risk ratio [RR] 1.43; 95% CI 1.14-1.78) and reduced pain scores (mean difference -1.97; 95% CI -2.49 to -1.46); rates of cesarean birth were similar between groups. Adverse events (eg, maternal hypotension, fetal bradycardia) were uncommon. Hypnosis – Hypnosis does not appear to be effective for pain relief during ECV , but may increase success rates as a result of maternal relaxation. POSTPROCEDURE Monitoring — After ECV, fetal well-being is evaluated by cardiotocography. We monitor the fetal heart rate (FHR) until it is stable and reactive rather than for a minimum period of time. It is common for FHR tracings to be nonreactive for 20 to 40 minutes after ECV. These changes may reflect the fetal response to a - Page 33 of 63 - External cephalic version transient period of stress caused by decreased uteroplacental blood flow during the procedure. The association between FHR abnormalities and ECV varies in the literature. In two prospective studies in which ECV was successful in 51 and 60 percent of cases, changes in FHR were noted in 9 and 28 percent of ECV attempts [123,124]. Very few patients (5/1266) required emergency cesarean birth: three for FHR abnormalities and two for vaginal bleeding, likely related to abruption. Transient fetal bradycardia was more frequently noted after successful ECV compared with unsuccessful ECV (37 versus 27 percent), suggesting that successful ECV imposes greater stress on the fetus. The presence of transient fetal bradycardia did not affect perinatal outcomes, such as fetal distress during labor or rates of vaginal birth, in either study. Anti-D-immune globulin — Anti-D immune globulin is administered to D-negative patients immediately after ECV; this is consistent with expert guidelines [39,70]. Given the extremely low risk of a large fetomaternal bleed, performing a Kleihauer-Betke or similar test to quantitate fetomaternal bleeding appears to be unnecessary before administration. (See "RhD alloimmunization: Prevention in pregnant and postpartum patients", section on 'Selective prophylaxis for pregnancy complications associated with fetomaternal bleeding'.) - Page 34 of 63 - External cephalic version Fetomaternal hemorrhage is almost always less than 30 mL. In a prospective study including over 1200 patients with a negative Kleihauer-Betke test before ECV, conversion to a positive test after the procedure occurred in 2.4 percent of patients. Of the 30 patients with a newly positive test, the majority (66 percent) had only rare fetal erythrocytes on the Kleihauer-Betke smear, 33 percent had an estimated bleed greater than 1 mL, and only 1 patient had an estimated bleed of 80 mL. Risk factors for fetomaternal bleeding could not be identified. Others have also reported rare cases of massive fetomaternal hemorrhage [127,128]. Management after successful ECV — Routine prenatal care is typically resumed after successful ECV. We agree with the American College of Obstetricians and Gynecologists to avoid immediate induction (also termed "stabilizing induction") in an attempt to minimize the chance of reversion , except in patients with other indications for induction of labor (eg, ≥39 weeks of gestation, unstable fetal lie [such as oblique or transverse lie, or repeated spontaneous change of lie]). In general, the rate of reversion to breech is small, while induction is associated with longer labors, increases the risk of neonatal morbidity if performed at