In VBAC (Vaginal Birth after Cesarean)

The American College of Obstetricians & Gynecologists (ACOG) has released an updated vaginal birth after cesarean (VBAC) Practice Bulletin, its first in seven years. The previous version came out in 2010, shortly after the landmark National Institutes of Health Consensus Conference on VBAC. That Bulletin was a substantial revision of its predecessor, published in 2004 (Childbirth Connection 2010). What about this newest iteration? Is it “same old, same old” or a step forward? I would argue that the new practice guideline takes baby steps in the right direction but no more than that. Here’s why:

First, the Good News . . .

Perhaps the most intriguing difference is that the 2017 Bulletin drops the requirement that staff be “immediately available” to provide emergency care. Instead, it recommends that VBAC labors “be attempted in facilities that can provide cesarean delivery for situations that are immediate threats to the life of the woman or fetus.” This may be a distinction without a difference, but perhaps not. A sticking point for offering VBAC has been the interpretation of “immediate” to mean the woman’s OB had to be on site throughout her labor. The new phrasing may open the way to alternative solutions.

Neither the 2017 nor the 2010 guideline, it should be added, proscribe VBAC in hospitals lacking 24/7 resources for emergency delivery. Both, however, recommend discussion between women and their doctors about the hospital’s resources where this is the case. Both also state that these hospitals should have a process for gathering staff, a plan for handling scar rupture, and that drills or other simulations could be useful in ensuring that the hospital is prepared.

Also under the heading of “Good News,” the 2017 Bulletin has an additional subhead under the “Labor Management” section entitled “Anticipated Labor Curve.” It explains that studies show that women with no prior vaginal birth should have labor progress judged according to the rate at which 1st-time mothers are expected to progress, not women who have had babies before. If taken to heart, this should result in more vaginal births.

Another new subsection, this one in the VBAC candidates section, discusses high BMI women. While noting that high BMI women are less likely to birth vaginally, it balances this by adding that high BMI women are also more likely to experience morbidity with elective repeat cesarean. (See the next section for a summary of the Bulletin’s recommendations.)

The rest of the “good news” differences are largely differences in placement. For example, the 2017 “Benefits and Risks” section begins: “In addition to providing an option for those who want to experience a vaginal birth, VBAC is associated with several potential health advantages for women,” which it goes on to list, whereas the same section in the 2010 Bulletin opens: “Neither elective repeat cesarean delivery nor TOLAC [trial of labor after cesarean] are without maternal or neonatal risk.” It includes the health advantages of VBAC too but not until the last paragraph. Similarly, the 2017 Bulletin begins the section on appropriate candidates for VBAC with, “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 and offered TOLAC,” while the 2010 Bulletin doesn’t make that statement until the final paragraph.

The 2017 Bulletin also has some slight differences in tone. For example, both versions state that centers that don’t offer VBAC may not use that policy to force women to agree to cesarean; however, the 2010 version reads: “Respect for patient autonomy also argues . . .,” and “transfer of care to facilities supporting TOLAC should be used rather than coercion,” while the 2017 version reads, “Respect for patient autonomy also dictates . . .,” [emphases mine] and makes the flat statement, “Coercion is not acceptable.”

What Are the 2017 Practice Bulletin’s Recommendations?

With a couple of additions, noted below, the two Practice Bulletins make the same recommendations:

  • Women with one prior cesarean with a low-transverse incision (the usual type) should be offered VBAC.
  • Misoprostol (Cytotec) should not be used to ripen the cervix or induce labor.
  • Epidural analgesia may be used. (The main body of the Bulletin elaborates that epidurals should neither be withheld, nor are they required. The reasoning behind withholding them is that they may mask pain arising from scar rupture, but the most common symptom of the scar giving way is fetal heart rate abnormalities. This, however, omits the consideration that episodes of abnormal fetal heart rate are a possible side-effect of epidurals that could lead to a misdiagnosis of scar rupture and consequent cesarean surgery [Mardirosoff 2002; Skupski 2009; Van de Velde 2004].)
  • Women at higher risk of scar rupture (classical vertical uterine incision, T-incision, prior scar rupture, prior uterine surgery) and women with contraindications for vaginal birth (e.g., placenta previa) are “not generally candidates” for planned VBAC.
  • Women with two prior low-transverse cesarean incisions may be candidates for VBAC and should be counseled based on the factors that affect their likelihood of vaginal birth. (See below for a discussion of the problems with this approach.)
  • Women with an unknown type of uterine scar are candidates unless there is high clinical suspicion that the prior cesarean was a classical vertical incision.
  • Women carrying twins who are otherwise appropriate candidates for vaginal birth are candidates for VBAC. (This is mostly irrelevant because few U.S. OBs allow vaginal birth of twins, period.)
  • Inducing labor remains an option.
  • External cephalic version (turning a breech baby head down in a hands-to-belly maneuver) is not contraindicated in women with a prior low-transverse incision.
  • NEW: Continuous fetal heart rate monitoring is recommended.
  • “After counseling, the ultimate decision to undergo TOLAC or a repeat cesarean delivery should be made by the patient in consultation with her obstetrician or obstetric care provider. The potential risks and benefits of both TOLAC and elective repeat cesarean delivery should be discussed.”
  • “[TOLAC] should be attempted at facilities capable of performing emergency deliveries.”
  • “Women attempting TOLAC should be cared for in a level 1 center (i.e. one that can provide basic care) or higher.”
  • TOLAC should be attempted “in facilities that can provide cesarean delivery for situations that are immediate threats to the life of the woman or fetus.” When this is not available obstetricians should discuss the availability of obstetric, pediatric, anesthesiology, and operating room staffs with women considering VBAC.
  • NEW: Home birth is contraindicated.

Missing from the “Summary of Recommendations” but in the main body of the Bulletin, are the following:

  • “Suspected macrosomia [big baby, generally defined as a baby anticipated to weigh more than 4000 g or 8 lb 13 oz] alone should not preclude offering TOLAC.”
  • “Gestational age greater than 40 weeks alone should not preclude TOLAC.”
  • “Recognizing the limitations of available data, the obstetrician . . . and patient may choose to proceed with TOLAC in the presence of a documented prior low-vertical uterine incision.”
  • High BMI reduces the chances of vaginal birth, but BMI is only one influencing factor, and high BMI women have higher rates of complications with elective repeat cesarean. “BMI alone should not be considered an absolute contraindication to TOLAC.”
  • “Similar standards should be used to evaluate the labor progress of women undergoing TOLAC and those who have not had a prior cesarean delivery.”
  • “Manual uterine exploration after VBAC and subsequent repair of asymptomatic scar [separation] have not been shown to improve outcomes.”
  • “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 may change.”

Now, the Bad News . . .

On the downside, the latest Practice Bulletin suffers from all the fundamental deficiencies of its 21st century predecessors.

First and foremost, wording such as “should not preclude VBAC,” “eliciting patient values and preferences is a key element of counseling,” “should not be considered an absolute contraindication, and “the obstetrician . . . and patient may choose to proceed” make clear that the Bulletin pays no more than lip service to women’s autonomy and their right to choose VBAC. Obstetricians, not women, cast the deciding vote. This breaches the fundamental principle that all competent adults, pregnant women not excepted, have the right to refuse any invasive procedure, let alone major surgery.

If there is any doubt on this point, the Bulletin provides an out when a woman won’t take “no” for an answer: “Referral may be appropriate if after discussion obstetricians . . . find themselves in disagreement with the choice the patient has made.” In reality, many obstetricians don’t provide a referral; they just dismiss recalcitrant women from their practice. Similarly, enjoining OBs and insurance carriers to “do all they can to facilitate transfer of care . . . in support of a desired TOLAC” amounts to so much hand washing since nothing compels them to do so. The Bulletin may state, as quoted above, that “coercion is not acceptable,” but making agreement to a repeat cesarean a condition of receiving care is coercion by definition.

Second, by putting strictures on what is required for safe VBAC, the Bulletin applies a double standard. If a hospital isn’t safe for a VBAC labor, then it isn’t safe for any woman to labor there. Emergencies may arise in any labor and are more likely to do so when there are medical complications such as hypertension. Emergencies may also arise as complications of inductions and epidurals, yet no one proposes limiting which hospitals may care for women with medical complications or perform labor inductions or epidurals.

Third, the emphasis remains on cherry picking candidates for VBAC, not on what policies and practices best promote safe, vaginal birth. The Bulletin even devotes an entire subsection to recommending a VBAC prediction calculator that can be used at the first prenatal visit to calculate a woman’s odds despite acknowledging that “no prediction model for VBAC has resulted in improved VBAC outcomes.”

Fourth, a bigger problem with focusing on determining VBAC odds is that it ignores the role played by labor management, a factor that far outweighs the woman’s characteristics. For example, the Bulletin notes that women who have had first cesareans for progress delay have lower VBAC rates than women whose first cesarean was for a nonrecurring indication such as breech or concern about fetal status, but a study found that women whose first cesarean was for progress delay were given 2 to 2 1/2 hours less time in the VBAC labor than women with a prior cesarean for a nonrecurring indication (Shipp 2000). Women with cesareans for progress delay would likely need more time to labor, not less. Similarly, the Bulletin also notes that women suspected of carrying bigger babies have lower VBAC rates. Studies of non VBAC labors consistently find that women are much more likely to have cesareans when doctors incorrectly believe the baby to be big than when the baby actually is big, but their doctors didn’t suspect it (Melamed 2010; Parry 2000; Sanchez-Ramos 2002; Vendittelli 2012; Vendittelli 2014). The reverse is also true. Women are more likely to have a vaginal birth when their doctor thinks the baby is average sized, but the baby is actually macrosomic. We have no reason to think that this wouldn’t apply to VBAC labors. Furthermore, studies find wide ranges in VBAC rates for women with the same characteristic. For example, rates range 57% to 72% in studies of VBAC after a cesarean for progress delay (Gonen 2004; Goodall 2005; Gyamfi 2004; Landon 2005; Shipp 2000; Spaans 2002; Srinivas 2007; Weinstein 1996). This much variation should have led guideline developers to consider what some practitioners were doing right that their colleagues were doing wrong, not just to reporting the status quo.

Fifth, the Bulletin avoids its responsibility to determine what constitutes optimal care. The section on labor induction notes an increased risk of scar rupture and a decreased likelihood of vaginal birth. It then dances around the issue of induction with an unfavorable cervix being a salient factor along with higher oxytocin doses but makes no recommendation on these points beyond ruling in induction as an option.

In fact, it equates medical-model management with optimal management. The induction section goes on to recommend induction at 39 weeks on the grounds that it produces higher VBAC rates than expectant management at 39 weeks (which would, by the way, not preclude the possibility of inducing labor beyond 39 weeks).

If ACOG had wanted to provide guidance on what best promotes safe, vaginal birth, it wouldn’t have had to look very far. Out-of-hospital (O-O-H) VBAC studies, where the model is physiologic care, report higher VBAC rates and lower scar rupture rates than quoted in the Bulletin. The Bulletin cites an overall scar rupture rate of 5 to 9 per 1000 VBAC labors. The rate in O-O-H studies is 4 per 1000 (Cox 2015; Lieberman 2004). The Bulletin recommends inducing at 39 weeks because induction achieved a 74% VBAC rate compared with a 61% rate with expectant management, according to one study (Palatnik 2015). Two O-O-H studies achieved an 87% VBAC rate with zero inductions (Cheyney 2014; Lieberman 2004). And the Bulletin omits telling us that the study they cite reported a scar rupture rate of 14 per 1000 with 39-week induction versus 4 per 1000 with expectant management.

This brings us to the Bulletin’s approach to O-O-H VBAC, which begins and ends with the statement that home birth is contraindicated because of the increased potential for adverse outcomes resulting from delay in obtaining treatment. The research confirms that potential, although it also shows that women with prior vaginal birth aren’t at increased risk (Bovbjerg 2017). However, ACOG’s position begs the question of why women choose O-O-H VBAC. For many, it’s because obstetricians and hospitals have left them with no other choice. O-O-H VBAC is their only option if they wish to avoid the hazards of accumulating cesarean surgeries to themselves, their babies, and future pregnancies. If women are choosing a riskier option, whose fault is it? Furthermore, some adverse outcomes arise from hospital staff who won’t work with O-O-H midwives to provide efficient, effective mechanisms for transfer of care LINK. If transfer is being delayed because of fear of legal repercussions in states where direct-entry midwives are illegal, or they’re legal but regulations forbid them to attend O-O-H VBACs, or because women transferring in are treated with hostility, or because care after transfer isn’t timely because the hospital won’t work with out-of-hospital midwives to handle transfers smoothly and expeditiously, whose fault is the resultant poor outcome? Failure to address this issue is nothing less than moral failure on ACOG’s part.

In the end, this latest Practice Bulletin provides a kind of Rorschach test, as did the ones that came before it. Progressive hospitals and obstetricians could see it as a mandate to assist women in making informed decisions about VBAC, to respect their right to choose planned VBAC despite not being optimal candidates, and to ensure that the hospital is as prepared as it can be to handle emergencies—the last of which has the added advantage of benefitting the rest of the women who labor there. On the other hand, hospitals could use the Bulletin to justify continuing what they were already doing, which is talking women out of attempting VBAC or, much more commonly, refusing VBAC altogether. Given that the 2010 Bulletin barely moved the needle on VBAC over a 7-year period, the smart money is on the latter.

The Take-Away

The struggle for VBAC doesn’t end with finding a doctor who agrees. You also have to determine whether the one you’ve found truly supports it. A fair number of obstetricians engage in bait-and-switch: They agree to a VBAC early on, but as the due date approaches, they become more and more discouraging. They start warning about risks or set up more and more hoops to jump through to qualify, and finally, they outright refuse if they can’t persuade a woman to change her mind. For this reason, choosing a VBAC provider must go beyond “Do you attend VBACs?” Asking these questions can help:

  • What percentage of women in your practice with prior cesareans plan VBACs? A low percentage is a red flag.
  • “What percentage of the women who plan VBACs have VBACs?” Unless the doctor has a convincing explanation for why, anything lower than the mid 70%s means VBAC management isn’t what it should be.
  • What are your criteria & policies for VBAC labors? The only factors the Practice Bulletin states as contraindicating VBAC are certain types of uterine scar as well as complications that would contraindicate vaginal birth under any circumstances, and the only recommended difference in care during labor is continuous fetal monitoring.
  • What happens if we disagree on whether to proceed with a VBAC or I decline a VBAC management policy? This is where you find out how much the doctor truly respects your right to make decisions.
  • Does everyone in the practice feel as you do about VBAC? If not, how can I ensure that I will be attended by someone who does? You don’t want to find yourself in the lurch because a pro-VBAC doctor isn’t on call when you go into labor.

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Learn more about vaginal birth after cesarean (VBAC) .

References

Bovbjerg ML, Cheyney M, Brown J, et al. Perspectives on risk: Assessment of risk profiles and outcomes among women planning community birth in the United States. Birth 2017.

Cheyney M, Bovbjerg M, Everson C, et al. Outcomes of care for 16,924 planned home births in the United States: The Midwives Alliance of North America statistics project, 2004 to 2009. J Midwifery Womens Health 2014;59(1):17-27.

Childbirth Connection. Comparison of American College of Obstetricians and Gynecologists VBAC Practice Bulletin 115 (2010) with VBAC Practice Bulletin 54 (2004) and Induction of Labor for VBAC Committee Opinion 342 (2006). 2010. (Accessed 2010, at [no longer available].)

Cox KJ, Bovbjerg ML, Cheyney M, et al. Planned Home VBAC in the United States, 2004-2009: Outcomes, Maternity Care Practices, and Implications for Shared Decision Making. Birth 2015.

Gonen R, Tamir A, Degani S, et al. Variables associated with successful vaginal birth after one cesarean section: a proposed vaginal birth after cesarean section score. Am J Perinatol 2004;21(8):447-53.

Goodall PT, Ahn JT, Chapa JB, et al. Obesity as a risk factor for failed trial of labor in patients with previous cesarean delivery. Am J Obstet Gynecol 2005;192(5):1423-6.

Gyamfi C, Juhasz G, Gyamfi P, et al. Increased success of trial of labor after previous vaginal birth after cesarean. Obstet Gynecol 2004;104(4):715-9.

Landon MB, Leindecker S, Spong CY, et al. The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery. Am J Obstet Gynecol 2005;193(3 Pt 2):1016-23.

Lieberman E, Ernst EK, Rooks JP, et al. Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol 2004;104(5 Pt 1):933-42.

Mardirosoff C, Dumont L, Boulvain M, et al. Fetal bradycardia due to intrathecal opioids for labour analgesia: a systematic review. BJOG 2002;109(3):274-81.

Melamed N, Yogev Y, Meizner I, et al. Sonographic prediction of fetal macrosomia: the consequences of false diagnosis. J Ultrasound Med 2010;29(2):225-30.

Palatnik A, Grobman WA. Induction of labor versus expectant management for women with a prior cesarean delivery. Am J Obstet Gynecol 2015;212(3):358 e1-6.

Parry S, Severs CP, Sehdev HM, et al. Ultrasonographic prediction of fetal macrosomia. Association with cesarean delivery. J Reprod Med 2000;45(1):17-22.

Sanchez-Ramos L, Bernstein S, Kaunitz AM. Expectant management versus labor induction for suspected fetal macrosomia: a systematic review. Obstet Gynecol 2002;100(5 Pt 1):997-1002.

Shipp TD, Zelop CM, Repke JT, et al. Labor after previous cesarean: influence of prior indication and parity. Obstet Gynecol 2000;95(6 Pt 1):913-6.

Shipp TD, Zelop CM, Repke JT, et al. Labor after previous cesarean: influence of prior indication and parity. Obstet Gynecol 2000;95(6 Pt 1):913-6.

Skupski DW, Abramovitz S, Samuels J, et al. Adverse effects of combined spinal-epidural versus traditional epidural analgesia during labor. Int J Gynaecol Obstet 2009;106(3):242-5.

Spaans WA, Sluijs MB, van Roosmalen J, et al. Risk factors at caesarean section and failure of subsequent trial of labour. Eur J Obstet Gynecol Reprod Biol 2002;100(2):163-6.

Srinivas SK, Stamilio DM, Stevens EJ, et al. Predicting failure of a vaginal birth attempt after cesarean delivery. Obstet Gynecol 2007;109(4):800-5.

Van de Velde M, Teunkens A, Hanssens M, et al. Intrathecal sufentanil and fetal heart rate abnormalities: a double-blind, double placebo-controlled trial comparing two forms of combined spinal epidural analgesia with epidural analgesia in labor. Anesth Analg 2004;98(4):1153-9, table of contents.

Vendittelli F, Riviere O, Breart G, et al. Is prenatal identification of fetal macrosomia useful? Eur J Obstet Gynecol Reprod Biol 2012;161(2):170-6.

Vendittelli F, Riviere O, Neveu B, et al. Does induction of labor for constitutionally large-for-gestational-age fetuses identified in utero reduce maternal morbidity? BMC Pregnancy Childbirth 2014;14:156.

Weinstein D, Benshushan A, Tanos V, et al. Predictive score for vaginal birth after cesarean section. Am J Obstet Gynecol 1996;174(1 Pt 1):192-8.

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