ACOG’s New VBAC Guidelines: Making (and Seeing) the Difference 15
As many people might have seen in the news, on press releases, or on blog posts, the American College of Obstetrics and Gynecology (ACOG) just released a revised version of its VBAC practice bulletin.
This is big news. It’s huge news. And it’s particularly big and huge in light of the fact that two previous practice bulletins on VBAC (from 1999 and 2004) were instrumental in leading to the decrease in VBAC access and the swath of VBAC bans across the United States. What’s more, this current bulletin has the potential to reverse some of the effects of the previous bulletins.
And this is not because it will effect any immediate policy changes but because it gives women a tool to help them facilitate discussions with their care providers and/or their local hospitals so that they can advocate for their birthing options.
So while the current document is not perfect, it’s an improvement. And a possibly giant improvement at that.
Just consider the introductory paragraph from the 2004 practice bulletin:
A trial of labor after previous cesarean delivery has been accepted as a way to reduce the overall cesarean delivery rate. Although vaginal birth after cesarean delivery (VBAC) is appropriate for most women with a history of low-transverse cesarean delivery, several factors increase the likelihood of a failed trial of labor, which in turn leads to increased maternal and perinatal morbidity. The purpose of this document is to review the current risks and benefits of VBAC in various situations and provide practical management guidelines.
And now the introductory paragraph from the new practice bulletin:
Trial of labor after previous cesarean delivery (TOLAC)* provides women who desire a vaginal delivery with the possibility of achieving that goal––a vaginal birth after cesarean delivery (VBAC)†. In addition to fulfilling a patient’s preference for vaginal delivery, at an individual level VBAC is associated with decreased maternal morbidity and a decreased risk of complications in future pregnancies. At a population level, VBAC also is associated with a decrease in the overall cesarean delivery rate (1, 2). Although TOLAC is appropriate for many women with a history of a cesarean delivery, several factors increase the likelihood of a failed trial of labor, which compared with VBAC, is associated with increased maternal and perinatal morbidity (3–5). Assessment of individual risks and the likelihood of VBAC is, therefore, important in determining who are appropriate candidates for TOLAC. The purpose of this document is to review the risks and benefits of TOLAC in various clinical situations and provide practical guidelines for managing and counseling patients who will give birth after a previous cesarean delivery.
While some people may find the “managing” language to be off-putting, I think that the changes in this paragraph signal both an acknowledgment of women’s birthing preferences and desires and some much-needed nuanced distinctions regarding VBAC and repeat cesarean outcomes. And an increased attention to detail and to women’s choices is a welcome difference.
Below, I’ve listed some additional major changes that ACOG has made to their practice bulletin on VBAC between 2004 and 2010. If you are are having a difficult time finding a VBAC-supportive care provider in your area, you might be able to draw her or his attention to these changes in order to advocate for the birth that you want!
*
On evaluating the risks and benefits of VBAC and elective repeat cesarean delivery
From the 2004 bulletin:
Neither elective repeat cesarean delivery nor VBAC is without risk. Generally, successful VBAC is associated with shorter maternal hospitalizations, less blood loss and fewer transfusions, fewer infections, and fewer thromboembolic events than cesarean delivery. However, a failed trial of labor may be associated with major maternal complications, such as uterine rupture, hysterectomy, and operative injury, as well as increased maternal infection and the need for transfusion. Neonatal morbidity is also increased with a failed trial of labor, as evidenced by the increased incidence of arterial umbilical cord blood gas pH levels below 7, 5-minute Apgar scores below 7, and infection. However, multiple cesarean deliveries also carry maternal risks, including an increased risk of placenta previa and accreta.
From the 2010 bulletin:
Neither elective repeat cesarean delivery nor TOLAC are without maternal or neonatal risk. 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 elective repeat cesarean delivery. Consequently, risk for maternal morbidity is integrally related to a woman’s probability of achieving VBAC…
…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 elective repeat cesarean delivery. 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.
*
On VBAC after multiple cesareans (or VBAmC)
From the 2004 bulletin:
Women who have had 2 previous low-transverse cesarean deliveries have traditionally been considered candidates for a trial of labor. However, the few studies that address this issue report a risk of uterine rupture ranging between 1% and 3.7%. In the only study that controlled for other potential confounding variables, the risk of uterine rupture during labor was nearly 5 times greater for women with 2 previous cesarean deliveries when compared with women who had 1 previous cesarean delivery. Women with a previous vaginal delivery followed by a cesarean delivery were only approximately one fourth as likely to sustain uterine rupture during a trial of labor. Therefore, for women with 2 prior cesarean deliveries, only those with a prior vaginal delivery should be considered candidates for a spontaneous trial of labor.
From the 2010 bulletin:
Studies addressing the risks and benefits of TOLAC in women with more than one cesarean delivery have
reported a risk of uterine rupture between 0.9% and 3.7%, but have not reached consistent conclusions regarding how this risk compares with women with only one prior uterine incision. Two large studies, with sufficient size to control for confounding variables, reported on the risks for women with two previous cesarean deliveries undergoing TOLAC. One study found no increased risk of uterine rupture (0.9% versus 0.7%) in women with one versus multiple prior cesarean deliveries (66), whereas the other noted a risk of uterine rupture that increased from 0.9% to 1.8% in women with one versus two prior cesarean deliveries. Both studies reported some increased risk in morbidity among women with more than one prior cesarean delivery, although the absolute magnitude of the difference in these risks was relatively small (eg, 2.1% versus 3.2% composite major morbidity in one study). Additionally, the chance of achieving VBAC appears to be similar for women with one or more than one 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.
*
On suspected macrosomia (or “big baby”)
From the 2004 bulletin:
Although macrosomia (usually birth weight greater than 4000 g or 4500 g, regardless of gestational age) is associated with a lower likelihood of successful VBAC, 60-90% of women attempting a trial of labor who give birth to infants with macrosomia are successful. The rate of uterine rupture appears to be increased only in those women without a previous vaginal delivery.
From the 2010 bulletin:
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.
*
On the “immediately availability” of obstetrical and surgical teams during a VBAC
From the 2004 bulletin:
Because uterine rupture may be catastrophic, VBAC should be attempted in institutions equipped to respond to emergencies with physicians immediately available to provide emergency care.
From the 2010 bulletin:
ShareA 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.







