The answers are unclear, experts note, but involve many factors, including economic incentives, law suits, America's risk-averse medical practice, and the resources available to hospitals.
For most of the 20th century, the NIH notes, it was assumed that a woman who had a cesarean section would need to deliver all future babies by the same procedure because the process of labor would put her at risk for a rupture of the uterus along the old incision mark -- a complication that can become deadly for the newborn within 15 minutes.
But considering the risk of complications with vaginal births is very small and can be addressed with proper emergency care, VBAC became more common in the 1980s and 1990s in an effort to lower cesarean rates, says Dr. Mark Landon, chief of obstetrics at Ohio State University Medical Center and VBAC researcher.
"Over the last decade, however, we seem to have lost interest in this process," he says, and now "everyone recognizes that far too many cesarean sections occur," but the rate continues to rise.
A major factor in this trend, says Dr. Lauren Streicher, obstetrician gynecologist at Northwestern Memorial Hospital, is the incentive structures in place that lead obstetricians to deliver babies by cesarean.
"Obstetricians must sit in labor for 12, 24 hours and cancel their office appointments," but they are not financially compensated for this time and effort. C-sections, on the other hand, pay out nearly twice as much, and can be scheduled for convenient times and done in an hour and a half.
There is also a tendency in the field, Streicher says, to say that birth problems that occur after a C-section were "unavoidable," while concluding that birth problems that occur in VBAC could have been avoided with a C-section. As a result, obstetricians are often plagued by malpractice suits when there are problems with a baby born vaginally.
One study presented at the conference, Jain notes, looked at the reasons some doctors had stopped offering VBAC that encapsulates the complicated nature of this trend.
The number one reason doctors stopped offering VBAC, the study said, was because a mother ruptured her uterus. The second most common reason cited by doctors was prior experience having a lawsuit, as Streicher highlights.
The number three reason given was a lack of available resources to handle a serious complication (such as a ruptured uterus) -- a problem which leads many small, rural hospitals to employ a no VBAC policy.
What's "alarming," Landon says, is that this VBAC "ban" is being extended to hospitals that are clearly equipped to deal with emergency birth situations, leading to unnecessary repeat cesarean procedures.
There is certainly a time and a need for both repeated cesarean deliveries and vaginal births, Streicher emphasized:
"It's really a case-by-case thing. You're not doing anyone any favors by having a 36-hour delivery -- the idea that a vaginal delivery is always better for mother and baby is simply not true."
But while often used in an attempt to reduce the risk of complications at all costs, "the pendulum has swung too far" in favor of C-sections, Landon says.
He feels that the conference will advise that "we need to start utilizing VBAC again."
Jain agrees that the consensus report will advise improved access to VBAC, but what's more, he feels confident it will provide a "balanced approach to the subject" and emphasize "giving the women the right to choose" which procedure and which risks they are willing to live with.