Once again, vaginal birth after cesarean, or VBAC—sometimes referred to as a trial of labor after cesarean, or TOLAC—has arisen as a topic of interest in obstetrics, as demonstrated in this issue of OBG Management.1 I say “once again” because, frankly, I thought that the matter had become irrelevant—reminiscent of a debate over vaginal breech delivery in the 1970s and 1980s now largely resolved in the United States, thanks to evidence-based randomized clinical trials.
I thought the issue was closed when, in 2005, the chair of ACOG’s Committee on Obstetric Practice was quoted in USA Today: “… the VBAC rupture rate may seem quite low but it’s damn high if you’re the one.” And later in the same article: “I think VBAC is dead.”
And I considered VBAC finished when I compared the target VBAC rate established in the US Department of Health and Human Services’s Healthy People 2010 report against the astounding data that we see reported today:
- In 1998, the US primary cesarean delivery rate was 18%; the Healthy People 2010 target was 15%. Today, that rate exceeds 25%.
- In 1998, the repeat cesarean delivery rate was 72%; again, the Healthy People 2010 target was 63%. In 2003, however, the repeat cesarean rate had climbed to 88.7%—and today, that rate exceeds 90%.
Called “reasonable” for many women
Yet, in a recent report, a consensus panel convened by The National Institutes of Health declares that VBAC is a “reasonable option” for many pregnant women. The panel encourages physicians to incorporate evidence-based data into the counseling they provide to patients.2
But even our own College admits to a paucity of high-quality evidence about VBAC. A 2009 ACOG Practice Bulletin says that “despite thousands of citations in the world’s literature there are currently no randomized trials comparing maternal or neonatal outcomes for both repeat cesarean delivery and VBAC.”3
So the question remains: How can medical science help patients and physicians make the best decisions about VBAC? Let me try to provide an answer here. Some of the ideas I draw on are discussed by Dr. Aviva Lee-Parritz in her article beginning on page 17.
What are the risks?
The true risks of VBAC are unknown. However, we do know—all the data are in agreement—that elective repeat cesarean delivery, performed at the appropriate gestational age, is safer for fetus and newborn than a trial of labor.4
We also know that most mothers accept a greater burden of risk for themselves if there is potential benefit for their newborn. (An example is expectant management of severe preeclampsia remote from term, when a delay in delivery offers no maternal benefit but does offer potential benefit to the newborn.) With VBAC, mothers must be willing to accept the risks of the procedure; better ways to assess that risk have been proposed to help them make a decision.5
What are the chances of success?
It amazes me when the quoted VBAC success rate at a given hospital exceeds the likelihood there of successful vaginal delivery of a nullipara. I see such data reported often.
Be certain that your patients know the hospital-specific cesarean delivery rate and VBAC success rate—and if you don’t have those data, then tell the patient that you don’t. It doesn’t make sense to quote an 85% VBAC success rate if your institution’s primary cesarean delivery rate is 25%.
What does VBAC cost?
The data with which to answer this question are hard to obtain cleanly; ultimately, however, the choices we make should be based on proper medical decision-making, not cost. That said, I remain unconvinced that VBAC overall offers significant savings over repeat cesarean delivery when total cost (not just the cost of postpartum care or the cost of post-delivery length of stay) is examined.
Furthermore, the expense of settling malpractice claims of “VBACs gone awry” is never included in estimates of the cost of care.
How are VBACs reimbursed?
The current structure of reimbursement for health care doesn’t favor VBAC. In most regions of the country, 1) physicians’ reimbursement for performing a VBAC is either the same as, or lower than, it is for cesarean delivery and 2) most hospitals enjoy a greater margin on the hospital stay postcesarean than after a vaginal delivery.
Given the increased time involved in managing a VBAC, a change in reimbursement to recognize the greater effort and exposure to liability would be a reasonable step for payers—if there is true interest in reversing the trend away from VBAC that we’re seeing.
How great are concerns over liability?