Guideline Synthesis:

Vaginal Birth After Cesarean (VBAC)

Guidelines Being Compared:  
  1. American College of Obstetricians and Gynecologists (ACOG). Vaginal birth after previous cesarean delivery. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2010 Aug. 14 p. (ACOG practice bulletin; no. 115). [136 references]
  2. Royal College of Obstetricians and Gynaecologists (RCOG). Birth after previous caesarean birth. London (UK): Royal College of Obstetricians and Gynaecologists (RCOG); 2007 Feb. 17 p. (Green-top guideline; no. 45). [116 references]
Areas of Agreement and Difference  

A direct comparison of recommendations presented in the above guidelines for the management of vaginal birth after cesarean (VBAC) is provided below.

Areas of Agreement

Candidates for VBAC

The American College of Obstetricians and Gynecologists (ACOG) and the Royal College of Obstetricians and Gynaecologists (RCOG) agree that that most women with a history of one or two uncomplicated low transverse caesarean sections, in an otherwise uncomplicated pregnancy at term and with no contraindications to vaginal birth, are candidates for and should be counseled about VBAC.

There is further agreement that women at high risk for complications—including those with a history of one classical or T-incision, or prior uterine rupture—are not generally candidates for VBAC. RCOG also cites a history of three or more previous caesarean deliveries as a contraindication to VBAC. ACOG notes that data regarding the risk for women undergoing TOLAC with more than two previous cesarean deliveries is limited. With regard to prior low-vertical incisions, ACOG states that recognizing the limitations of available data, health care providers and patients may choose to proceed with TOLAC in the presence of a documented prior low vertical uterine incision. RCOG cites prior inverted T- or J-incisions and prior low vertical incisions as variants associated with an increased risk of uterine rupture.

ACOG and RCOG provide recommendations for VBAC in special circumstances. Concerning twin gestation, ACOG concluded that women with one previous cesarean delivery with a low transverse incision, who are otherwise appropriate candidates for twin vaginal delivery, may be considered candidates for TOLAC. With regard to macrosomia, ACOG states that it is appropriate for health care providers and patients to consider past and predicted birth weights when making decisions regarding TOLAC, but suspected macrosomia alone should not preclude the possibility of TOLAC. RCOG does not make specific recommendations, noting that study sample sizes are underpowered to provide reliable evidence suitable for any clinical practice recommendation in relation to twin gestation, fetal macrosomia and short interdelivery interval. They advise that a cautious approach be used when considering planned VBAC in women with these circumstances, as there is uncertainty in the safety and efficacy of planned VBAC in such situations. Both groups also address other special circumstances. ACOG discusses gestation beyond 40 weeks, breech presentation, unknown type of uterine decision, second trimester delivery/delivery of an intrauterine fetal demise; RCOG discusses preterm birth.

Induction and Augmentation of Labor

ACOG and RCOG agree that induction of labor for maternal or fetal indications is an option for women undergoing a TOLAC. There is further agreement that when informing a woman about induction (prostaglandin or non-prostaglandin methods) and/or augmentation, clear information should be provided on all potential risks and benefits, especially the potential increased risk of uterine rupture and the potential decreased possibility of achieving VBAC. RCOG specifies that the decision to induce, the method chosen, the decision to augment with oxytocin, the time intervals for serial vaginal examination and the selected parameters of progress that would necessitate and advise on discontinuing VBAC should be discussed with the woman by a consultant obstetrician.

Both ACOG and RCOG address the use of prostaglandins for induction of labor, with ACOG recommending against the use of misoprostol (PGE1) for third trimester cervical ripening or labor induction in patients who have had a cesarean delivery or major uterine surgery. With regard to dinoprostone (PGE2), ACOG states that it is difficult to make definitive recommendations regarding its use, and cites one large study that found an increase in uterine rupture only when oxytocin was used after cervical ripening with prostaglandins. Therefore, ACOG continues, selecting women most likely to give birth vaginally while avoiding sequential use of prostaglandins and oxytocin appears to have the lowest risks of uterine rupture. RCOG does not differentiate between PGE1 and PGE2, but recommends women be informed of the higher risk of uterine rupture with induction of labor with prostaglandins. Given the risks and the absence of direct robust evidence, RCOG continues, it is important not to exceed the safe recommended limit for prostaglandin priming in women with prior caesarean birth. Due consideration should be given to restricting the dose and adopting a lower threshold of total prostaglandin dose exposure.

With regard to augmentation using oxytocin, ACOG concludes that available studies support its use in patients undergoing TOLAC. RCOG states that the additional risks in augmented VBAC mean that: although augmentation is not contraindicated it should only be preceded by careful obstetric assessment, maternal counseling, and by a consultant-led decision; and that oxytocin augmentation should be titrated such that it should not exceed the maximum rate of contractions of four in 10 minutes; the ideal contraction frequency would be three to four in 10 minutes. RCOG also recommends careful serial cervical assessments be performed for both augmented and non-augmented labors to ensure adequate cervicometric progress.

ACOG addresses mechanical cervical ripening and induction with a transcervical catheter, and concludes that given the lack of compelling data suggesting increased risk, such interventions may be an option for TOLAC candidates with an unfavorable cervix.

Antenatal Counseling

Both groups agree that women with a prior caesarean birth should be counseled regarding potential maternal and perinatal risks (most notably uterine rupture), as well as benefits of both VBAC and ERCS. There is also agreement that the discussion should be tailored to the patient's individual circumstances so that she can choose her intended mode of birth based on personally relevant information. RCOG specifies that individual characteristics that should be discussed include: her personal motivation and preferences to achieve VBAC or ERCS; her attitudes towards the risk of rare but serious adverse outcomes; her plans for future pregnancies; and her chance of a successful VBAC (principally whether she has previously had a vaginal birth). ACOG notes that it is preferable to discuss VBAC early in a woman's prenatal care course, and that antenatal counseling should be adapted to any circumstances that may change the risks or benefits of TOLAC as the pregnancy progresses. ACOG also recommends that counseling consider the resources available to support women electing TOLAC at their intended delivery site, and whether such resources match those recommended for caring for women electing TOLAC. RCOG and ACOG agree that reasonable attempts should be made to review the operative notes of the previous cesarean (especially if the type of previous uterine incision is in doubt).

RCOG recommends that women be informed that planned VBAC carries: a 22-74/10,000 risk of uterine rupture (compared to virtually no risk of rupture in ERCS); a 1% additional risk of either blood transfusion or endometritis compared with ERCS; an 8/10,000 risk of the infant developing HIE; and a 2-3/10,000 additional risk of birth-related perinatal death when compared with ERCS (comparable to the risk for women having their first birth). One advantage of VBAC compared to ERCD addressed by both groups is the avoidance of potential future maternal consequences of multiple cesarean deliveries. An additional benefit cited by ACOG is the avoidance of major abdominal surgery, resulting in lower rates of hemorrhage, infection, and a shorter recovery period. Additionally, RCOG notes that attempting VBAC probably reduces the risk that the baby will have respiratory problems after birth: rates are 2-3% with planned VBAC and 3-4% with ERCS.

RCOG recommends that women be informed that, overall, the chances of successful planned VBAC are 72-76%. ACOG states that most published series of women attempting TOLAC have demonstrated a probability of VBAC of 60-80%. The groups agree that the probability that a woman attempting TOLAC will achieve VBAC depends on her individual combination of factors. There is agreement that factors associated with unsuccessful VBAC include: induced labor, no prior vaginal birth, advanced gestational age (≥40 weeks), advanced maternal age, high maternal BMI, high birth weight, previous cesarean section for a recurring indication, and non-white ethnicity.

Both groups address scoring systems that have been developed to predict the likelihood of VBAC success or uterine rupture in planned VBAC. RCOG notes that their usefulness in assisting women to make the decision about whether VBAC or ERCS is the best choice in their personal situation remains to be determined. ACOG states that while most of the scoring models have had limited success, one model was developed specifically for women undergoing TOLAC at term with one prior low transverse cesarean delivery incision, singleton pregnancy, and cephalic fetal presentation, and it may have utility for patient education and counseling for those considering TOLAC at term.

Intrapartum Management

ACOG and RCOG agree that planned VBAC should be undertaken in a suitably staffed and equipped delivery suite at a facility capable of providing emergency care (most notably emergency cesarean section deliveries), with obstetric, anesthetic, operating room, and neonatal/pediatric/midwifery staff support continuously available. When resources for immediate cesarean delivery are not available, ACOG recommends that health care providers and patients discuss the hospital's resources and availability of necessary staffs, and carefully consider the decision to offer and pursue TOLAC in a setting in which the option of immediate cesarean delivery is more limited. If the appropriate resources are not available, potential alternatives to consider early in the course of antenatal care cited by ACOG include: referral of patients to a facility with available resources and the creation of regional centers where patients interested in TOLAC can be readily referred and needed resources can be more efficiently and economically mobilized. ACOG notes, however, that in areas with fewer deliveries and greater distances between delivery sites, organizing transfers or accessing referral centers may be untenable. ACOG adds that respect for patient autonomy supports the concept that patients should be allowed to accept increased levels of risk; however, patients should be clearly informed of such potential increase in risk and management alternatives. They emphasize that none of the principles, options, or processes outlined in the guideline should be used by centers, health care providers, or insurers to avoid appropriate efforts to provide the recommended resources to make TOLAC as safe as possible for those who choose this option.

Both groups recommend continuous electronic fetal monitoring and intrapartum care for the duration of planned VBAC to enable prompt identification and management of uterine scar rupture. According to ACOG, uterine rupture is often sudden and may be catastrophic, and accurate antenatal predictors of uterine rupture do not exist. RCOG similarly notes that there is no single pathognomic clinical feature that is indicative of uterine rupture. Both groups agree, however, that signs/symptoms of uterine rupture to be vigilant for include: fetal and/or maternal heart rate abnormality; loss of fetal station of the presenting part; excessive vaginal bleeding or hematuria; and new onset of uterine scar pain/tenderness. ACOG also cites increased uterine contractions; RCOG also cites severe abdominal pain, chest pain or shoulder tip pain, and cessation of previously efficient uterine activity.

There is further agreement that epidural analgesia may be used in planned VBAC. ACOG notes that adequate pain relief may encourage more women to choose TOLAC. They add that effective regional analgesia should not be expected to mask signs and symptoms of uterine rupture, particularly because the most common sign of rupture is fetal heart tracing abnormalities.

With regard to intrauterine pressure catheters, RCOG notes that their routine use in the early detection of uterine scar rupture is not recommended. ACOG similarly states that no data suggest that intrauterine pressure catheters are superior to external forms of monitoring, and there is evidence that their use does not assist in the diagnosis of uterine rupture.

Areas of Difference

There are no significant areas of difference between the guidelines.

Comparison of Recommendations  

Candidates for VBAC

ACOG
(2010)

The following recommendations are based on good and consistent scientific evidence (Level A):

  • Most women with one previous cesarean delivery with a low-transverse incision are candidates for and should be counseled about VBAC and offered TOLAC.

The following recommendations are based on limited or inconsistent scientific evidence (Level B):

  • Women with two previous low transverse cesarean deliveries may be considered candidates for TOLAC.
  • Women with one previous cesarean delivery with a low transverse incision, who are otherwise appropriate candidates for twin vaginal delivery, may be considered candidates for TOLAC.
  • External cephalic version for breech presentation is not contraindicated in women with a prior low transverse uterine incision who are at low risk for adverse maternal or neonatal outcomes from external cephalic version and TOLAC.
  • Those at high risk for complications (e.g., those with previous classical or T-incision, prior uterine rupture, or extensive transfundal uterine surgery) and those in whom vaginal delivery is otherwise contraindicated (e.g., those with placenta previa) are not generally candidates for planned TOLAC.
  • TOLAC is not contraindicated for women with previous cesarean delivery with an unknown uterine scar type unless there is a high clinical suspicion of a previous classical uterine incision.

Who are candidates for a trial of labor after previous cesarean delivery?

Good candidates for planned TOLAC are those women in whom the balance of risks (low as possible) and chances of success (as high as possible) are acceptable to the patient and health care provider. The balance of risks and benefits appropriate for one patient may seem unacceptable for another. Because delivery decisions made during the first pregnancy after a cesarean delivery will likely affect plans in future pregnancies, decisions regarding TOLAC should ideally consider the possibility of future pregnancies.

Although there is no universally agreed on discriminatory point, evidence suggests that women with at least a 60-70% chance of VBAC have equal or less maternal morbidity when they undergo TOLAC than women undergoing ERCD. Conversely, women who have a lower than 60% probability of VBAC have a greater chance of morbidity than women undergoing repeat cesarean delivery. Similarly, because neonatal morbidity is higher in the setting of a failed TOLAC than in VBAC, women with higher chances of achieving VBAC have lower risks of neonatal morbidity. One study demonstrated that composite neonatal morbidity is similar between TOLAC and ERCD for the women with the greatest probability of achieving VBAC.

The preponderance of evidence suggests that most women with one previous cesarean delivery with a low transverse incision are candidates for and should be counseled about VBAC and offered TOLAC. Conversely, those at high risk for complications (e.g., those with previous classical or T-incision, prior uterine rupture, or extensive transfundal uterine surgery) and those in whom vaginal delivery is otherwise contraindicated are not generally candidates for planned TOLAC. Individual circumstances must be considered in all cases, and if, for example, a patient who may not otherwise be a candidate for TOLAC presents in advanced labor, the patient and her health care providers may judge it best to proceed with TOLAC. Some common situations that may modify the balance of risks and benefits are considered as follows.

More Than One Previous Cesarean Delivery

Given the overall data, it is reasonable to consider women with two previous low transverse cesarean deliveries to be candidates for TOLAC, and to counsel them based on the combination of other factors that affect their probability of achieving a successful VBAC. Data regarding the risk for women undergoing TOLAC with more than two previous cesarean deliveries are limited.

Macrosomia

Women undergoing TOLAC with a macrosomic fetus (defined variously as birth weight greater than 4,000-4,500 g) have a lower likelihood of VBAC than women attempting TOLAC who have a nonmacrosomic fetus. Similarly, women with a history of past cesarean delivery performed for the indication of dystocia, have a lower likelihood of VBAC if the current birth weight is greater than that of the index pregnancy with dystocia. Some limited evidence also suggests that the uterine rupture rate is increased (relative risk 2.3, P<.001) for women undergoing TOLAC without a prior vaginal delivery and neonatal birth weights greater than 4,000 g. These studies used actual birth weight as opposed to estimated fetal weight thus limiting the applicability of these data when making decisions regarding mode of delivery antenatally. Despite this limitation, it remains appropriate for health care providers and patients to consider past and predicted birth weights when making decisions regarding TOLAC, but suspected macrosomia alone should not preclude the possibility of TOLAC.

Gestation Beyond 40 Weeks

Studies evaluating the association of gestational age with VBAC outcomes have consistently demonstrated decreased VBAC rates in women who undertake TOLAC beyond 40 weeks of gestation. Although one study has shown an increased risk of uterine rupture beyond 40 weeks of gestation, other studies, including the largest study that has evaluated this factor, have not found this association. Although chances of success may be lower in more advanced gestations, gestational age of greater than 40 weeks alone should not preclude TOLAC.

Previous Low Vertical Incision

The limited number of studies that have evaluated TOLAC in women with prior low vertical uterine incisions have reported similar rates of successful vaginal delivery compared with women with a previous low transverse uterine incision. In addition, there has not been consistent evidence of an increased risk of uterine rupture, or maternal or perinatal morbidity associated with TOLAC in the presence of a prior low vertical scar. Recognizing the limitations of available data, health care providers and patients may choose to proceed with TOLAC in the presence of a documented prior low vertical uterine incision.

Unknown Type of Previous Uterine Incision

The type of uterine incision performed at the time of a prior cesarean delivery cannot be confirmed in some patients. Although some have questioned the safety of offering VBAC under these circumstances, two case series, both from large tertiary care facilities, reported rates of VBAC success and uterine rupture similar to those from other contemporaneous studies of women with documented previous low transverse uterine incisions. Additionally, in one study evaluating risk factors for uterine rupture, no significant association was found with the presence of an unknown scar. The absence of an association may result from the fact that most cesarean incisions are low transverse, and the uterine scar type can often be inferred based on the indication for the prior cesarean delivery. Therefore, TOLAC is not contraindicated for women with one previous cesarean delivery with an unknown uterine scar type unless there is a high clinical suspicion of a previous classical uterine incision.

Twin Gestation

The studies of women with twin gestations who attempt VBAC have consistently demonstrated that their outcomes are similar to those of women with singleton gestations who attempt VBAC. In two analyses of large populations, women with twin gestations had a similar chance of achieving VBAC as women with singleton gestations and did not incur any greater risk of uterine rupture or maternal or perinatal morbidity. Women with one previous cesarean delivery with a low transverse incision, who are otherwise appropriate candidates for twin vaginal delivery, may be considered candidates for TOLAC.

How should future pregnancies be managed after uterine rupture?

If the site of the ruptured scar is confined to the lower segment of the uterus, the rate of repeat rupture or dehiscence in labor is 6%. If the scar includes the upper segment of the uterus, the repeat rupture rate has been reported to be as high as 32%. Given both these rates, it is recommended that women who have had a previous uterine rupture should give birth by repeat cesarean delivery before the onset of labor. Because spontaneous labor is unpredictable and could occur before the recommended 39 weeks for an elective delivery, earlier delivery should be contemplated with consideration given to amniocentesis to document fetal lung maturity.

How should second trimester delivery or delivery of an intrauterine fetal demise be accomplished in women with a previous cesarean delivery?

Some women with a history of a cesarean delivery will require delivery during the second trimester in a subsequent pregnancy. Although published series are relatively small, women with a prior cesarean delivery who undergo labor induction with prostaglandins (including misoprostol) have been shown to have outcomes that are similar to those women with an unscarred uterus (e.g., length of time until delivery, failed labor induction, and complication rates). The frequency of uterine rupture with labor induction in this setting in most series is less than 1%. For these women, dilation and evacuation as well as labor induction with prostaglandins are reasonable options.

In patients after 28 weeks of gestation with an intrauterine fetal demise and a prior cesarean scar, cervical ripening with a transcervical Foley catheter has been associated with uterine rupture rates comparable with spontaneous labor and this may be a helpful adjunct in patients with an unfavorable cervical examination. Because there are no fetal risks to TOLAC in these circumstances, TOLAC should be encouraged, and after the patient and the health care provider weigh the risks and benefits, TOLAC may even be judged appropriate for women at higher risk for cesarean scar complications (e.g., prior classical uterine incision).

RCOG
(2007; reaffirmed 2012)

How should women be counselled in the antenatal period?

GPP - Women with a prior history of one uncomplicated lower-segment transverse caesarean section, in an otherwise uncomplicated pregnancy at term, with no contraindication to vaginal birth, should be able to discuss the option of planned VBAC and the alternative of an ERCS.

What are the contraindications to VBAC?

GPP - Women with a prior history of one classical caesarean section are recommended to give birth by ERCS.

C - Women with a previous uterine incision other than an uncomplicated low transverse caesarean section incision who wish to consider vaginal birth should be assessed by a consultant with full access to the details of the previous surgery.

B - Women with a prior history of two uncomplicated low transverse caesarean sections, in an otherwise uncomplicated pregnancy at term, with no contraindication for vaginal birth, who have been fully informed by a consultant obstetrician, may be considered suitable for planned VBAC.

There is limited evidence on whether maternal or neonatal outcomes are significantly influenced by the number of prior caesarean births or type of prior uterine scar. Nonetheless, due to higher absolute risks of uterine rupture or unknown risks, planned VBAC is contraindicated in women with:

  • Previous uterine rupture-risk of recurrent rupture is unknown
  • Previous high vertical classical caesarean section (200-900/10,000 risk of uterine rupture) where the uterine incision has involved the whole length of the uterine corpus.
  • Three or more previous caesarean deliveries (reliable estimate of risks of rupture unknown).

However, it is recognised that, in certain extreme circumstances (such as miscarriage, intrauterine fetal death) for some women in the above groups, the vaginal route (although risky) may not necessarily be contraindicated. A number of other variants are associated with an increased risk of uterine rupture. These include: women with a prior inverted T or J incision (190/10,000 rupture risk) and women with prior low vertical incision (200/10,000 rupture risk).

Planned VBAC in Special Circumstances

How should women be counselled in the context of obstetric complications?

Preterm Birth

B - Women who are preterm and considering the options for birth after a previous caesarean should be informed that planned preterm VBAC has similar success rates to planned term VBAC but with a lower risk of uterine rupture. Therefore, following appropriate counselling and in a carefully selected population, planned VBAC may be offered as an option to women undergoing preterm birth with a history of prior caesarean birth.

Twin Gestation, Fetal Macrosomia, Short Interdelivery Interval

C - A cautious approach is advised when considering planned VBAC in women with twin gestation, fetal macrosomia and short interdelivery interval, as there is uncertainty in the safety and efficacy of planned VBAC in such situations.

Study sample sizes are underpowered to provide reliable evidence suitable for any clinical practice recommendation in relation to twin gestation, fetal macrosomia and short interdelivery interval.

Induction and Augmentation of Labor (Back to top)

ACOG
(2010)

The following recommendations are based on good and consistent scientific evidence (Level A):

  • Misoprostol should not be used for third trimester cervical ripening or labor induction in patients who have had a cesarean delivery or major uterine surgery.

The following recommendations are based on limited or inconsistent scientific evidence (Level B):

  • Induction of labor for maternal or fetal indications remains an option in women undergoing TOLAC.

Induction and Augmentation of Labor

Induction of labor for maternal or fetal indications remains an option for women undergoing TOLAC. However, the potential increased risk of uterine rupture associated with any induction, and the potential decreased possibility of achieving VBAC, should be discussed. Several studies have noted an increased risk of uterine rupture in the setting of induction of labor in women attempting TOLAC.

Studies of the effects of prostaglandins, grouped together as a class of agents, on uterine rupture in women with a prior cesarean delivery have demonstrated inconsistent results. Among three large studies investigating prostaglandins for induction of labor for women with a previous cesarean delivery, one found an increased risk of uterine rupture, a second reported no increased rupture risk, and a third found no increased risk of rupture when prostaglandins were used alone (with no subsequent oxytocin). Studies of specific prostaglandins are limited in size, but indicate that rupture risk may vary among these agents. Evidence from small studies shows that the use of misoprostol (prostaglandin E1) in women who have had cesarean deliveries is associated with an increased risk of uterine rupture. Therefore, misoprostol should not be used for third trimester cervical ripening or labor induction in patients who have had a cesarean delivery or major uterine surgery.

Because data are limited, it is difficult to make definitive recommendations regarding the use of prostaglandin E2. One large study found an increase in uterine rupture only when oxytocin was used after cervical ripening with prostaglandins. Therefore, selecting women most likely to give birth vaginally while avoiding sequential use of prostaglandins and oxytocin appears to have the lowest risks of uterine rupture.

Induced labor is less likely to result in VBAC than spontaneous labor. There is some evidence that this is the case regardless of whether the cervix is favorable or unfavorable, although an unfavorable cervix decreases the chance of success to the greatest extent. These factors may affect patient and health care provider decisions as they consider the risks and benefits of TOLAC associated with labor induction.

The use of oxytocin for augmentation of contractions, separate from induction of labor, during TOLAC has been examined in several studies. Some have found an association between oxytocin augmentation and uterine rupture whereas others have not. The varying outcomes of available studies and small absolute magnitude of the risk reported in those studies support that oxytocin augmentation may be used in patients undergoing TOLAC.

Studies on TOLAC outcomes after mechanical cervical ripening and labor induction with a transcervical catheter are retrospective and have relatively small sample sizes. Two studies showed no increase in the risk of uterine rupture whereas another reported an increase compared with women in spontaneous labor. Similar to other methods of cervical ripening and labor induction, it is unknown whether any increased risk is due to an unfavorable cervix or the method of ripening. Given the lack of compelling data suggesting increased risk with mechanical dilation and transcervical catheters, such interventions may be an option for TOLAC candidates with an unfavorable cervix.

RCOG
(2007; reaffirmed 2012)

Induction and Augmentation

How should women with a previous caesarean birth be advised in relation to induction of labour or augmentation?

B - Women should be informed of the two- to three-fold increased risk of uterine rupture and around 1.5-fold increased risk of caesarean section in induced and/or augmented labours compared with spontaneous labours.

GPP - Women should be informed that there is a higher risk of uterine rupture with induction of labour with prostaglandins.

GPP - There should be careful serial cervical assessments, preferably by the same person, for both augmented and non-augmented labours, to ensure that there is adequate cervicometric progress, thereby allowing the planned VBAC to continue.

GPP - The decision to induce, the method chosen, the decision to augment with oxytocin, the time intervals for serial vaginal examination and the selected parameters of progress that would necessitate and advise on discontinuing VBAC should be discussed with the woman by a consultant obstetrician.

Given the risks and the absence of direct robust evidence, it is important not to exceed the safe recommended limit for prostaglandin priming in women with prior caesarean birth. Due consideration should be given to restricting the dose and adopting a lower threshold of total prostaglandin dose exposure. Importantly, the decision to induce and the method chosen (prostaglandin or non-prostaglandin methods) should be consultant-led.

There is no direct evidence to recommend what is acceptable or unacceptable cervicometric progress in women being augmented with a previous caesarean birth. Among women with unscarred uteri, it is suggested that there is unlikely to be a higher vaginal birth rate if augmentation continues beyond 6–8 hours. Awareness of the increased risk of uterine rupture in scarred uteri justifies adopting a more conservative threshold to the upper limit of augmentation in women with prior caesarean birth.

The additional risks in augmented VBAC mean that:

  • Although augmentation is not contraindicated it should only be preceded by careful obstetric assessment, maternal counselling and by a consultant-led decision
  • Oxytocin augmentation should be titrated such that it should not exceed the maximum rate of contractions of four in 10 minutes; the ideal contraction frequency would be three to four in 10 minutes
  • Careful serial cervical assessments, preferably by the same person, are necessary to show adequate cervicometric progress, thereby allowing augmentation to continue.

The intervals for serial vaginal examination and the selected parameters of progress that would necessitate discontinuing VBAC labour should be consultant-led decisions.

When informing a woman about induction (prostaglandin or non-prostaglandin methods) and/or augmentation, clear information should be provided on all potential risks and benefits of such a decision and how this may impact on her long-term health. For example, women who are contemplating future pregnancies may accept the short-term additional risks associated with induction and/or augmentation in view of the reduced risk of serious complications in future pregnancies if they have a successful VBAC.

Antenatal Counseling (Back to top)

ACOG
(2010)

The following recommendations are based primarily on consensus and expert opinion (Level C):

  • After counseling, the ultimate decision to undergo TOLAC or a repeat cesarean delivery should be made by the patient in consultation with her health care provider. The potential risks and benefits of both TOLAC and ERCD should be discussed. Documentation of counseling and the management plan should be included in the medical record.

How should women considering a trial of labor after previous cesarean delivery be counseled?

The interest in considering TOLAC varies greatly among women, and this variation is at least partly related to differences in the way individuals value the potential risks and benefits. Accordingly, potential benefits and risks of both TOLAC and ERCD should be discussed and these discussions documented. Discussion should consider individual characteristics that affect the chances of complications associated with VBAC and TOLAC so that a patient can choose her intended route of delivery based on data that is most personally relevant.

A discussion of VBAC early in a woman's prenatal care course, if possible, will allow the most time for her to consider options for TOLAC or ERCD. Many of the factors that are related to the chance of VBAC or uterine rupture are known early in pregnancy. If the type of previous uterine incision is in doubt, reasonable attempts should be made to obtain the patient's medical records. As the pregnancy progresses, if other circumstances arise that may change the risks or benefits of TOLAC (e.g., need for labor induction), these should be addressed. Counseling also may include consideration of intended family size and the risk of additional cesarean deliveries, with the recognition that the future reproductive plans may be uncertain or change.

Counseling should consider the resources available to support women electing TOLAC at their intended delivery site, and whether such resources match those recommended for caring for women electing TOLAC. Available data support that TOLAC may be safely undertaken in both university and community hospitals and facilities with and without residency programs.

After counseling, the ultimate decision to undergo TOLAC or a repeat cesarean delivery should be made by the patient in consultation with her health care provider. Global mandates for TOLAC are inappropriate because individual risk factors are not considered. Documentation of counseling and the management plan should be included in the medical record.

What are the risks and benefits associated with a trial of labor after previous cesarean delivery?

Neither ERCD nor TOLAC are without maternal or neonatal risk (see Table 1 and Table 2 in the original guideline document). The risks of either approach include maternal hemorrhage, infection, operative injury, thromboembolism, hysterectomy, and death. Most maternal morbidity that occurs during TOLAC occurs when repeat cesarean delivery becomes necessary. Thus, VBAC is associated with fewer complications, and a failed TOLAC is associated with more complications, than ERCD. Consequently, risk for maternal morbidity is integrally related to a woman’s probability of achieving VBAC.

Uterine rupture or dehiscence is the outcome associated with TOLAC that most significantly increases the chance of additional maternal and neonatal morbidity. The reported incidence of uterine rupture varies, in part because some studies have grouped true, catastrophic uterine rupture together with asymptomatic scar dehiscence. Additionally, early case series did not stratify rupture rates by the type of prior cesarean incision (ie, low transverse versus classical).

One factor that markedly influences the chance of uterine rupture is the location of the prior incision on the uterus. Several large studies of women with a prior low transverse uterine incision reported a clinically determined uterine rupture rate of approximately 0.5-0.9% after TOLAC. As discussed as follows, the risk of uterine rupture is higher in women with other types of hysterotomies.

In addition to providing an option for those who want the experience of a vaginal birth, VBAC has several potential health advantages for women. Women who achieve VBAC avoid major abdominal surgery, resulting in lower rates of hemorrhage, infection, and a shorter recovery period compared with ERCD. Additionally, for those considering larger families, VBAC may avoid potential future maternal consequences of multiple cesarean deliveries such as hysterectomy, bowel or bladder injury, transfusion, infection, and abnormal placentation such as placenta previa and placenta accreta.

What is the vaginal delivery rate in women undergoing a trial of labor after previous cesarean delivery?

Most published series of women attempting TOLAC have demonstrated a probability of VBAC of 60-80%. However, the chance of VBAC for an individual varies based on demographic and obstetric characteristics (see box in the original guideline document). For example, women whose first cesarean delivery was performed for an arrest of labor disorder are less likely than those whose first cesarean delivery was for a nonrecurring indication (e.g., breech presentation) to succeed in their attempt at VBAC.

Similarly, there is consistent evidence that women who undergo labor induction or augmentation are less likely to have VBAC when compared with those at the same gestational age with spontaneous labor without augmentation. Other factors that negatively influence the likelihood of VBAC include increasing maternal age, high body mass index, high birth weight, and advanced gestational age at delivery. A shorter interdelivery interval and the presence of preeclampsia at the time of delivery also have been associated with a reduced chance of achieving VBAC. Conversely, women who have had a prior vaginal delivery are more likely than those who have not to succeed in their TOLAC.

The probability that a woman attempting TOLAC will achieve VBAC depends on her individual combination of factors. Several investigators have attempted to create scoring systems to assist in the prediction of VBAC, but most have had limited success. However, one model was developed specifically for women undergoing TOLAC at term with one prior low transverse cesarean delivery incision, singleton pregnancy, and cephalic fetal presentation. This model may have utility for patient education and counseling for those considering TOLAC at term (http://www.bsc.gwu.edu/mfmu/vagbirth.html).

RCOG
(2007; reaffirmed 2012)

Antenatal Counselling

How should women be counselled in the antenatal period?

GPP - Women with a prior history of one uncomplicated lower-segment transverse caesarean section, in an otherwise uncomplicated pregnancy at term, with no contraindication to vaginal birth, should be able to discuss the option of planned VBAC and the alternative of an ERCS.

GPP - The antenatal counselling of women with a prior caesarean birth should be documented in the notes. There should be provision of a patient information leaflet with the consultation.

GPP - A final decision for mode of birth should be agreed between the woman and her obstetrician before the expected/planned delivery date (ideally by 36 weeks of gestation).

GPP - A plan for the event of labour starting prior to the scheduled date should be documented.

B - Women considering their options for birth after a single previous caesarean should be informed that, overall, the chances of successful planned VBAC are 72-76%.

All women who have experienced a prior caesarean birth should be counselled about the maternal and perinatal risks and benefits of planned VBAC and ERCS when deciding the mode of birth. The key issues to include in the discussion are listed below under specific risks and benefits.

The risks and benefits should be discussed in the context of the woman's individual circumstances, including her personal motivation and preferences to achieve vaginal birth or ERCS, her attitudes towards the risk of rare but serious adverse outcomes, her plans for future pregnancies and her chance of a successful VBAC (principally whether she has previously had a vaginal birth; (see below). In addition, where possible, there should be review of the operative notes of the previous caesarean to identify the indication, type of uterine incision and any perioperative complications.

As up to 10% of women scheduled for ERCS go into labour before the 39th week, it is good practice to have a plan for the event of labour starting prior to the scheduled date.

A number of factors are associated with successful VBAC. Previous vaginal birth, particularly previous VBAC, is the single best predictor for successful VBAC and is associated with an approximately 87-90% planned VBAC success rate. Risk factors for unsuccessful VBAC are: induced labour, no previous vaginal birth, body mass index greater than 30, previous caesarean section for dystocia. When all these factors are present, successful VBAC is achieved in only 40% of cases. There are numerous other factors associated with a decreased likelihood of planned VBAC success: VBAC at or after 41 weeks of gestation, birth weight greater than 4000 g; no epidural anaesthesia, previous preterm caesarean birth, cervical dilatation at admission less than 4 cm, less than 2 years from previous caesarean birth, advanced maternal age, non-white ethnicity, short stature and a male infant. Where relevant to the woman’s circumstances, this information should be shared during the antenatal counselling process to enable the woman to make the best informed choice.

There is limited and conflicting evidence on whether the cervical dilatation achieved at the primary caesarean for dystocia impacts on the subsequent VBAC success rate. Unfortunately, the NICHD study was unable to address this concern as data relating to the labour of the primary caesarean were not collected during the study.

Several preadmission and admission-based multivariate models have been developed to predict the likelihood of VBAC success or uterine rupture in planned VBAC. However, their usefulness in assisting women to make the decision about whether VBAC or ERCS is the best choice in their personal situation remains to be determined.

What are the specific risks and benefits of VBAC?

B - Women considering the options for birth after a previous caesarean should be informed that planned VBAC carries a risk of uterine rupture of 22-74/10,000. There is virtually no risk of uterine rupture in women undergoing ERCS.

B - Women considering the options for birth after a previous caesarean should be informed that planned VBAC compared with ERCS carries around 1% additional risk of either blood transfusion or endometritis.

B - Women considering planned VBAC should be informed that this decision carries a 2-3/10,000 additional risk of birth-related perinatal death when compared with ERCS. The absolute risk of such birth-related perinatal loss is comparable to the risk for women having their first birth.

B - Women considering the options for birth after a previous caesarean should be informed that planned VBAC carries an 8/10,000 risk of the infant developing HIE. The effect on the long-term outcome of the infant upon experiencing HIE is unknown.

B - Women considering the options for birth after a previous caesarean should be informed that attempting VBAC probably reduces the risk that their baby will have respiratory problems after birth: rates are 2-3% with planned VBAC and 3-4% with ERCS.

B - Women considering the options for birth after a previous caesarean should be informed that the risk of anaesthetic complications is extremely low, irrespective of whether they opt for planned VBAC or ERCS.

B - Women considering the options for birth after a previous caesarean should be informed that ERCS may increase the risk of serious complications in future pregnancies.

Intrapartum Management (Back to top)

ACOG
(2010)

The following recommendations are based on good and consistent scientific evidence (Level A):

  • Epidural analgesia for labor may be used as part of TOLAC.

The following recommendations are based primarily on consensus and expert opinion (Level C):

  • A trial of labor after previous cesarean delivery should be undertaken at facilities capable of emergency deliveries. Because of the risks associated with TOLAC and that uterine rupture and other complications may be unpredictable, the College recommends that TOLAC be undertaken in facilities with staff immediately available to provide emergency care. When resources for immediate cesarean delivery are not available, the College recommends that health care providers and patients considering TOLAC discuss the hospital’s resources and availability of obstetric, pediatric, anesthetic, and operating room staffs. Respect for patient autonomy supports that patients should be allowed to accept increased levels of risk, however, patients should be clearly informed of such potential increase in risk and management alternatives.

How does management of labor differ for patients undergoing vaginal birth after cesarean delivery?

Analgesia

Epidural analgesia for labor may be used as part of TOLAC, and adequate pain relief may encourage more women to choose TOLAC. No high quality evidence suggests that epidural analgesia is a causal risk factor for an unsuccessful TOLAC. In addition, effective regional analgesia should not be expected to mask signs and symptoms of uterine rupture, particularly because the most common sign of rupture is fetal heart tracing abnormalities.

Other Elements of Intrapartum Management

Once labor has begun, a patient with TOLAC should be evaluated by her obstetric provider. Most authorities recommend continuous electronic fetal monitoring. No data suggest that intrauterine pressure catheters or fetal scalp electrodes are superior to external forms of monitoring, and there is evidence that the use of intrauterine pressure catheters does not assist in the diagnosis of uterine rupture.

Personnel familiar with the potential complications of TOLAC should be present to watch for fetal heart rate patterns that are associated with uterine rupture. Uterine rupture is often sudden and may be catastrophic, and accurate antenatal predictors of uterine rupture do not exist. Acute signs and symptoms of uterine rupture are variable and may include fetal bradycardia, increased uterine contractions, vaginal bleeding, loss of fetal station, or new onset of intense uterine pain. However, the most common sign associated with uterine rupture is fetal heart rate abnormality, which has been associated with up to 70% of cases of uterine ruptures. This supports the recommendation of continuous fetal heart rate monitoring in labor.

Delivery

There is nothing unique about the delivery of the fetus or placenta during VBAC. Manual uterine exploration after VBAC and subsequent repair of asymptomatic scar dehiscence have not been shown to improve outcomes. Excessive vaginal bleeding or signs of hypovolemia are potential signs of uterine rupture and should prompt complete evaluation of the genital tract.

What resources are recommended for health care providers and facilities offering a trial of labor after previous cesarean delivery?

Trial of labor after previous cesarean delivery should be undertaken at facilities capable of emergency deliveries. ACOG (the College) and international guidelines have recommended that resources for emergency cesarean delivery should be "immediately available." Some have argued that this stipulation and the difficulty in providing required resources—especially in smaller centers with lower delivery volumes—limit women's access to TOLAC. This may be particularly true in rural areas where the option to travel to larger centers is difficult.

Restricting access was not the intention of the College’s past recommendation. Much of the data concerning the safety of TOLAC was obtained from centers capable of performing immediate, emergency cesarean delivery. Although there is reason to think that more rapid availability of cesarean delivery may provide a small incremental benefit in safety, comparative data examining in detail the effect of alternate systems and response times are not available.

Because of the risks associated with TOLAC and that uterine rupture and other complications may be unpredictable, the College recommends that TOLAC be undertaken in facilities with staff immediately available to provide emergency care. When resources for immediate cesarean delivery are not available, the College recommends that health care providers and patients considering TOLAC discuss the hospital's resources and availability of obstetric, pediatric, anesthetic, and operating room staffs. These recommendations are concordant with those of other professional societies. The decision to offer and pursue TOLAC in a setting in which the option of immediate cesarean delivery is more limited should be carefully considered by patients and their health care providers. In such situations the best alternative may be to refer patients to a facility with available resources. Another alternative is to create regional centers where patients interested in TOLAC can be readily referred and needed resources can be more efficiently and economically organized. Health care providers and insurance carriers should do all they can to facilitate transfer of care or co-management in support of a desired TOLAC, and such plans should be initiated early in the course of antenatal care. However, in areas with fewer deliveries and greater distances between delivery sites, organizing transfers or accessing referral centers may be untenable. Respect for patient autonomy supports the concept that patients should be allowed to accept increased levels of risk, however, patients should be clearly informed of such potential increase in risk and management alternatives. Evaluation of a patient's individual chance of VBAC and risk for uterine rupture are central to these considerations. Such conversations and decisions should be documented, including reference to site-specific resources and anticipated risks. Referral also may be appropriate if, after discussion, health care providers find themselves uncomfortable with choices patients have made. Importantly, however, none of the principles, options, or processes outlined here should be used by centers, health care providers, or insurers to avoid appropriate efforts to provide the recommended resources to make TOLAC as safe as possible for those who choose this option. In settings where the staff needed for emergency delivery are not immediately available, the process for gathering needed staff when emergencies arise should be clear, and all centers should have a plan for managing uterine rupture. Drills or other simulation may be useful in preparing for these rare emergencies.

Respect for patient autonomy also argues that even if a center does not offer TOLAC, such a policy cannot be used to force women to have cesarean delivery or to deny care to women in labor who decline to have a repeat cesarean delivery. When conflicts arise between patient wishes and health care provider or facility policy or both, careful explanation and, if appropriate, transfer of care to facilities supporting TOLAC should be used rather than coercion. Because relocation after the onset of labor is generally not appropriate in patients with a prior uterine scar, who are thereby at risk for uterine rupture, transfer of care to facilitate TOLAC, as noted previously, is best effected during the course of antenatal care. This timing places a responsibility on patients and health care providers to begin relevant conversations early in the course of prenatal care.

RCOG
(2007; reaffirmed 2012)

Intrapartum Support and Intervention During Planned VBAC

Where and how should VBAC be conducted?

B - Women should be advised that planned VBAC should be conducted in a suitably staffed and equipped delivery suite, with continuous intrapartum care and monitoring and available resources for immediate caesarean section and advanced neonatal resuscitation.

Obstetric, midwifery, anaesthetic, operating theatre, neonatal and haematological support should be continuously available throughout planned VBAC and ERCS.

C - Epidural anaesthesia is not contraindicated in planned VBAC.

B - Women should be advised to have continuous electronic fetal monitoring following the onset of uterine contractions for the duration of planned VBAC.

GPP - Continuous intrapartum care is necessary to enable prompt identification and management of uterine scar rupture.

Early diagnosis of uterine scar rupture followed by expeditious laparotomy and resuscitation is essential to reduce associated morbidity and mortality in mother and infant. There is no single pathognomic clinical feature that is indicative of uterine rupture but the presence of any of the following peripartum should raise the concern of the possibility of this event:

  • Abnormal cardiotocograph (CTG)
  • Severe abdominal pain, especially if persisting between contractions
  • Chest pain or shoulder tip pain, sudden onset of shortness of breath
  • Acute onset scar tenderness
  • Abnormal vaginal bleeding or haematuria
  • Cessation of previously efficient uterine activity
  • Maternal tachycardia, hypotension or shock
  • Loss of station of the presenting part

The diagnosis is ultimately confirmed at emergency caesarean section or postpartum laparotomy.

C - The routine use of intrauterine pressure catheters in the early detection of uterine scar rupture is not recommended.

Strength of Evidence and Recommendation Grading Schemes  

ACOG
(2010)

Studies were reviewed and evaluated for quality according to the method outlined by the U.S. Preventive Services Task Force.

I Evidence obtained from at least one properly designed randomized controlled trial.

II-1 Evidence obtained from well-designed controlled trials without randomization.

II-2 Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.

II-3 Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.

III Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

Based on the highest level of evidence found in the data, recommendations are provided and graded according to the following categories:

Level A - Recommendations are based on good and consistent scientific evidence.

Level B - Recommendations are based on limited or inconsistent scientific evidence.

Level C - Recommendations are based primarily on consensus and expert opinion.

RCOG
(2007; reaffirmed 2012)

Levels of Evidence

Ia: Evidence obtained from meta-analyses of randomised controlled trials

Ib: Evidence obtained from at least one randomised controlled trial

IIa: Evidence obtained from at least one well-designed controlled study without randomisation

IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study

III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies

IV: Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities

The recommendations were graded according to the level of evidence upon which they were based. The grading scheme used was based on a scheme formulated by the Clinical Outcomes Group of the National Health Service Executive.

Grade A - Requires at least one randomised controlled trial as part of a body of literature of overall good quality and consistency addressing the specific recommendation. (Evidence levels Ia, Ib)

Grade B - Requires the availability of well controlled clinical studies but no randomised clinical trials on the topic of recommendations. (Evidence levels IIa, IIb, III)

Grade C - Requires evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. Indicates an absence of directly applicable clinical studies of good quality. (Evidence level IV)

Methodology  

Click on the links below for details of guideline development methodology

ACOG
(2010)

RCOG
(2007; reaffirmed 2012)

To collect and select the evidence, both groups performed searches of electronic databases; ACOG also performed hand-searches of published literature (primary and secondary sources). Both groups provide the names of the databases searched and date ranges applied. ACOG and RCOG both weighted the quality and strength of the evidence according to a rating scheme and provide the scheme. To analyze the evidence, both groups reviewed published meta-analyses and performed a systematic review (the RCOG review incorporated evidence tables). Expert consensus was employed by both groups to formulate the recommendations, and both rate the strength of the recommendations according to a scheme. Concerning issues of cost, neither group performed a formal cost analysis or reviewed published cost analyses. To validate the guidelines, ACOG and RCOG sought internal peer review; RCOG also sought external peer review.

Benefits and Harms  

Benefits

ACOG
(2010)
  • Women who achieve VBAC avoid major abdominal surgery, resulting in lower rates of hemorrhage, infection, and a shorter recovery period compared with ERCD.
  • For those considering larger families, VBAC may avoid potential future maternal consequences of multiple cesarean deliveries such as hysterectomy, bowel or bladder injury, transfusion, infection, and abnormal placentation such as placenta previa and placenta accreta.
RCOG
(2007; reaffirmed 2012)

Appropriate counseling and decision making regarding mode of delivery after previous cesarean birth

Harms

ACOG
(2010)
  • The risks of either TOLAC or ERCD include maternal hemorrhage, infection, operative injury, thromboembolism, hysterectomy, and death.
  • A failed TOLAC is associated with more complications than ERCD.
  • Uterine rupture or dehiscence is the outcome associated with TOLAC that most significantly increases the chance of additional maternal and neonatal morbidity.
  • Neonatal morbidity is higher in the setting of a failed TOLAC than in a VBAC.
RCOG
(2007; reaffirmed 2012)
  • Rates of hysterectomy and transfusion increase in women undergoing VBAC following two or more previous caesarean births compared to a single previous caesarean birth.
  • Planned VBAC carries a risk of uterine rupture of 22-74/10,000. There is virtually no risk of uterine rupture in women undergoing ERCS. Planned VBAC compared with ERCS carries around 1% additional risk of either blood transfusion or endometritis.
  • Planned VBAC carries a 2-3/10,000 additional risk of birth-related perinatal death when compared with ERCS.
  • Planned VBAC carries an 8/10,000 risk of the infant developing HIE.
  • There is an increased risk of neonatal respiratory morbidity* among term infants delivered by elective caesarean (3.5-3.7%) compared with vaginal birth (0.5-1.4%).
  • The following risks significantly increase with increasing number of repeated caesarean deliveries: placenta accreta; injury to bladder, bowel or ureter; ileus; the need for postoperative ventilation; intensive care unit admission; hysterectomy; blood transfusion requiring four or more units and the duration of operative time and hospital stay.
  • Infants of mothers who received epidural analgesia were more likely to be subjected to diagnostic tests and therapeutic interventions (including sepsis evaluation and antibiotic treatment) compared with infants from a matched no-epidural analgesia group
  • There is a higher risk of uterine rupture with induction of labour with prostaglandins.

*Neonatal respiratory morbidity is defined as the combined rate of transient tachypnoea of the newborn (TTN) and respiratory distress syndrome (RDS).

Contraindications  

ACOG
(2010)

Contraindications for VBAC

  • Previous classical or T-shaped incision or extensive transfundal uterine surgery
  • Previous uterine rupture
  • Women in whom vaginal delivery is otherwise contraindicated (e.g., those with placenta previa)
RCOG
(2007; reaffirmed 2012)

Due to higher absolute risks of uterine rupture or unknown risks, planned vaginal birth after previous caesarean section is contraindicated in women with:

  • Previous uterine rupture—risk of recurrent rupture is unknown
  • Previous high vertical classical caesarean section (200-900/10,000 risk of uterine rupture) where the uterine incision has involved the whole length of the uterine corpus.
  • Three or more previous caesarean deliveries (reliable estimate of risks of rupture unknown)

However, it is recognized that, in certain extreme circumstances (such as miscarriage, intrauterine fetal death) for some women in the above groups, the vaginal route (although risky) may not necessarily be contraindicated.

Abbreviations  

ACOG, American College of Obstetricians and Gynecologists

ERCD, elective repeat cesarean delivery

ERCS, elective repeat cesarean section

HIE, hypoxic ischemic encephalopathy

PGE, prostaglandin

RCOG, Royal College of Obstetricians and Gynaecologists

TOLAC, trial of labor after cesarean

VBAC, vaginal birth after cesarean section

Status  

This synthesis was prepared by ECRI Institute on October 20, 2010.

Citation  

Internet citation: National Guideline Clearinghouse (NGC). Guideline synthesis: Vaginal birth after cesarean (VBAC). In: National Guideline Clearinghouse (NGC) [Web site]. Rockville (MD): Agency for Healthcare Research and Quality (AHRQ); 2011 Jan. [cited YYYY Mon DD]. Available: http://www.guideline.gov.