VBAC trend put in reverse
Complications seen higher in labor
By Elgin K. Kennedy, MD
Editor, The Assertive Utilization and Quality Report
Costa Mesa, CA
A major trend of the cost-conscious 90s has been to try to encourage less-expensive VBACs (vaginal birth after cesarean sections) whenever possible. This trend has been based on the assumption that C-sections are both more expensive and cause more complications than vaginal deliveries. However, a large new study provides a contrary view on complication rates and may now be used by obstetricians who wish to justify the appropriateness of their high C-section rates.1
Previous studies had shown that among women who attempt a trial of labor (TOL) after a previous low transverse C-section, 60% to 80% will complete vaginal deliveries. Morbidity is lower for those women than for those who choose to go straight to a second C-section. What has been unrecognized until now is that the rate of complications among the remainder of patients who fail the trial of labor and must undergo another C-section is higher than anticipated.
The authors of the 1996 study examined 6,138 deliveries in women who had previously undergone a C-section with delivery of a singleton live infant. The study showed:
• Major complications were nearly twice as likely among the women who chose to begin a TOL compared to those who went straight to elective repeat C-section (ERCS).
Much of the morbidity occurred in those patients who failed their TOL and therefore had another C-section.
• Minor complications were not significantly different (puerperal fever, transfusion, abdominal-wound infection).
• Infant complications were not significantly different (Apgar scores, admission to a neonatal intensive care unit, perinatal mortality).
Clearly, the best approach would be to consider a trial of labor only for those women who will be successful, with the remainder going straight to elective C-section. Unfortunately, while guidelines exist, there are as yet no confirmed methods available that can make an accurate prediction.
The American College of Obstetricians and Gynecologists provides the following contraindications to VBAC:2
• previous "classical" uterine incision (i.e., not a low transverse incision);
• twins, triplets, etc. (multiple infants);
• breech presentation.
Other references suggest that the following criteria provide some rough guidelines for predicting a greater chance of failure of a trial of labor:
• previous dysfunctional labor;
• no prior vaginal delivery;
• abnormal fetal heart rate tracing;
• induction of labor;
• fetal pelvic disproportion;
• infant birth weight over 4,000 gm;
• fetal growth abnormalities;
• delivery in other than a tertiary care center.
Some hospitals continue to have C-section rates as high as 25% or more despite their best efforts to reduce them. In part, such high rates exist because patients, not their doctors, choose their method of delivery. While it is the job of physicians and other caregivers to provide counseling and a fair appraisal of the risks, ethically the patient has the absolute right of choice.
Another complexity is that caregivers may have a variety of incentives to advise one choice over the other. A common issue is the convenience of an elective C-section for both the patient and physician. Another is that fee-for-service reimbursement can provide an incentive to the caregiver to provide the more expensive C-section. Some managed care companies have purposefully reduced their C-section reimbursement in an attempt to control this inappropriate incentive.
The other side of this coin is that capitation may favor the less expensive vaginal delivery because the extra costs of a C-section come from the caregiver’s pocket. Worse, physicians with high C- section rates may be unfairly deselected by their managed care companies they may lose the opportunity to continue to take care of the managed care companies’ patients because of their high C-section rates. (See article on C-sections, p. 130.)
Many hospitals have been working long and hard on trying to reduce their C-section rates because managed care companies often prefer to contract with hospitals with the lowest rates. Sometimes only one or two physicians out of a dozen are responsible for a hospital’s high rates.
This study that provides a contrary view on complication rates is likely to put a crimp in the effort of hospitals trying to reduce their high C-section rates. While the percentage differences in outcomes were not very large total major complications of 1.6% vs. 0.8% the study was large and carefully performed, and the differences were statistically significant. The cost benefits of a trial of labor persist, but it will no longer be possible to use a quality of care argument when trying to reduce C-section rates.
References
1. McMahon MJ, Luther ER, Bowes WA, et al. Comparison of a trial of labor with an elective second cesarean section. New Engl J Med 1996; 335:689-695.
2. American College of Obstetricians and Gynecologists. Practice Patterns 1995; August:1-8.
(Editor’s note: This article was published in The Assertive Utilization and Quality Report, December 1996. For more information on the publication, contact Elgin Kennedy, MD, at 204 Second Ave., No. 334, San Mateo, CA 94401. Telephone: (415) 348-3647.)
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