VOL. 90, NO. 2, AUGUST 1997

For most of this century, "once a cesarean, always a cesarean" was the rule in the United States. In the 1980s, vaginal birth after cesarean grew in popularity and the pendulum began to swing away from routine repeat cesarean delivery. Recently, the wisdom of this transition has been questioned. As the 20th century comes to a close, the treatment of the patient with a prior cesarean delivery remains controversial.

(Obstet Gynecol 1997;90:312-5. c 1997 by The American College of Obstetricians and Gynecologists.) beginning on page 312 0029-7844/97/$17.00 PII S0029-7844(97)00263-9

From the Department of Obstetrics and Gynecology, Kaiser Permanente Medical, Riverside, Califortiia.

The Historical Controversy

The phrase, "once a cesarean, always a cesarean" dates back to an article by Edwin Cragin entitled "Conservatism in Obstetrics" published in 1916.[1] Although cesarcan delivery rarely was performed in that era, Cragin's purpose was to urge physicians to avoid unnecessary cesarians. He termed the cesarean operation "radical obstetric surgery" and urged his colleagues to practice sound obstetrics to avoid having to resort to it. The famous "once a cesarean, always a cesarean" phrase came in the final paragraph of the article and clearly was meant to emphasize that one of the risks of a primary cesarean is that repeat operations might be required. Interestingly, the author went on to point out that there are many exceptions to this rule and that one of his own patients had 3 vaginal births after cesarean without difficulty. This is remarkable given that vertical uterine incisions were standard at that time. The low transverse uterine incision would be championed by Kerr [2] a decade later.

Before 1950, vaginal birth after cesarean (VBAC) was common in Europe but rare in the United States. In a 1931-1950 review from the Margaret Hague Maternity Hospital in New Jersev, Cosgrove [3] reported more than 100 cases and noted that one of his patients delivered 12 full-term infants after her initial and only cesarean. The heated discussion that followed Cosgrove's presentation at the 1950 annual meeting of the American Medical Association clearly demonstrated the controversy surrounding VBAC in that era. During the 1950s, more than 200 women attempted VBAC at the Walter Reed Army Medical Center, with no serious complications.

By 1979, more than 1000 women had attempted trial of labor at the University of Texas, with no fetal deaths due to uterine rupture [5] Overall, between 1950 and 1980, more than 5000 trials of labor were reported in the English literature, with no matemal deaths and few fetal deaths.[6] Between 1980 and 1984, 21 more articles on VBAC were published, bringing the total number of cases reported to more than 10,000.[7] By the late 1980s, large multicenter studies [8,9] involving thousands of patients had confirmed the relative safety of VBAC. Few topics in obstetrics have been subjected to such intense scrutiny. As evidence for the safety of VBAC mounted, the national rate of routine repeat cesarean began to decline. The percentage of women with a previous cesarean operation who delivered vaginally in the United States increased from 3.4% in 1980 to almost 25/o in 1993. The number of VBACs exceeded the 100,000 per year mark in 1993. [10]

The Risk Controversy

Large studies [8,9] have confirmed that the risk of uterine rupture during trial of labor is approximately 1% and that, even in these cases, matemal and perinatal outcomes are usually favorable. However, these studies took place in large medical centers staffed with in-house physicians and operating room personnel available to perform emergency cesareans at any time of day or night, Thus, although the incidence of uterine rupture in other settings may be similar, the outcomes may be different. Because isolated complications at rural hospitals generally are not published, there may be an underreporting bias that masks unfavorable outcomes associated with uterine rupture.

In 1991, two reports [11,12] raised serious concerns about the safety of VBAC. A survey of five hospitals in the Denver area identified eight uterine ruptures, and a similar survey of five hospitals in the Salt Lake City area identified 12 ruptures. Because these were case series rather than cohort studies, the denominators were not known, but the incidence of uterine rupture in the Denver series was estimated to be approximately 0.7%, which is consistent with the results of several large studies. What was disturbing was not the incidence of uterine rupture but the number of catastrophic outcomes.

Among 20 uterine ruptures in the combined Denver-Salt Lake City series, there were four perinatal deaths and two infants with long-term neurologic impairment. Although there were no matemal deaths in either report, the perinatal outcomes were worrisome. Careful reading of these reports reveals that three of the four perinatal deaths involved women who labored at home, and two of these three women presented to the hospital with a dead fetus. In an editorial that accompanied these two reports, Pitkin [13] pointed out that the observations from two uncontrolled case series do not negate the value of dozens of large cohort studies indicating a low risk of complications with VBAC. However, he also pointed out that a trial of labor should not be managed in a cavalier or superficial manner.

The Benchmark Controversy

Over the past 30 years, more than 50 studies have documented the safety of VBAC.[6-9] These studies confirmed that trial of labor carries little risk, but they did not compare risk directly with elective repeat cesarean. Two recent studies [14,15] have done this, with disparate results. A prospective study [14] in the United States compared 5022 women attempting trial of labor with 2207 women delivered by elective repeat cesarean and found fairly similar outcomes in both groups, although the hospital length of stay, incidence of postpartum fever, and incidence of postpartum transfusion all were significantly higher in the elective cesarean group.

A Canadian study [15] compared 3249 women attempting trial of labor with 2889 women delivered by elective repeat cesarean and found major matemal complications to be almost twice as likely in the trial of labor group. There is some question about the validity of this conclusion, because extension of the uterine incision was coded as a major complication whereas wound infections and hemorrhage requiring transfusion (both more common in the elective cesarean group) were coded as minor complications. In any case, the incidence of major complications was quite low in both groups, slightly less than 1% in the elective cesarean group and slightly more than 1% in the trial of labor group. Nevertheless, several major US newspapers reported the study's results with the headline "VBAC twice as risky as repeat cesarean." The large Canadian study[15] focused on matemal outcomes, but two fetal deaths due to uterine rupture were mentioned, again emphasizing that VBAC is not risk-free.

The ideal benchmark study would be a randomized, controlled trial in which large numbers of women with prior cesareans are assigned randomly to trial of labor or elective repeat cesarean. Because many patients have strong feelings for or against VBAC, enrolling a sufficient number of women willing to adhere to random assignment to VBAC or cesarean may not be feasible. Although the ideal benchmark study may never be conducted, large prospective cohort studies [14,15] are reassuring in that they suggest that the vast majority of outcomes will be favorable with either trial of labor or elective repeat cesarean.

The Ethical Controversy

When to offer, recommend, or perform a cesarean operation is a common ethical challenge that only will increase with the growing influence of managed care. [16] For the physician, elective repeat cesarean offers advantages, including convenience, time savings, and sometimes increased compensation. Elective repeat cesarean also is convenient for the patient and her family. The most recent revision of the ACOG committee opinion on vaginal delivery after a previous cesarean birth recommends that the mode of delivery ultimately should be based on the specific clinical circumstances and the patient's choice after appropriate counseling. [17] This still leaves the physician with the dilemma of determining exactly what constitutes appropriate counseling. It also does not address the issue of the patient who strongly requests a VBAC but then demands a cesarean in the midst of labor. Although most doctors would not even consider complying with such a request made by a woman with no prior cesarean, the situation is far more complex during a trial of labor. An outline of potential methods for dealing with these difficult situations has been published recently.[18]

The Legal Controversy

Perhaps the most distressing aspect of the continuing VBAC saga involves the specter of huge malpractice claims. Many physicians earnestly want to avoid unnecessary repeat cesarean operations but fear that they will be found legally liable if any untoward event occurs during a trial labor. These fears have recently been borne out in a multimillion dollar verdict ($98.5 million verdict in missed uterine rupture. Ob-Gyn Malpractice Prevention 1996;3:41-3). One recent article (Phelan JP. VBAC: Time to reconsider? OBG Management 1996;11: 62-8) even suggested that it may be time to return to a policy of "once a cesarean, always a cesarean."

The article was prompted by a catastrophic uterine rupture resulting in the birth of a child with cerebral palsy. The fetal heart rate (FHR) apparently was normal until it suddenly decreased to 80 beats per minute when the patient's cervix reached 9 cm dilation. The deceleration persisted, but the time elapsed between its onset and the emergency cesareandelivery was 27 minutes. The doctor was sued and lost the case. The court concluded that "the ACOG 30-minute rule represented the maximum period of elapse," implying that having a baby delivered in 30 minutes is not good enough in some situations. Because of this verdict, the article proposes the use of a VBAC consent form that includes the statement "I understand that if my uterus ruptures during my VBAC, there may not be sufficient time to operate and to prevent the death of or permanent brain injury to my baby," with the acknowledgement that few women would be willing to sign such a consent form.

However, at least one major medical malpractice insurance company (Cooperative of American Physicians, Inc., Mutual Protection Trust) already has mailed a modification of this consent form to all their member obstetricians along with a cover letter strongly recommending that they use it. The insurance company's form has been modified to include an additional statement warning that the risk of fetal death or permanent infant brain damage may be as high as 50% in cases of uterine rupture. The revised form also wams that the matemal risks of uterine rupture include, but are not limited to, hysterectomy, blood transfusion, infection, injury to internal organs (bowel, bladder, ureter), blood coagulation problems, and death. No risks for elective repeat cesarean are listed. The patient is required to initial each of the above statements separately.

Widespread implementation of this or similar consent forms essentially would mean the end of VBAC. I think that would be a serious mistake. At the hospital where I practice, there is a VBAC almost every day of the year, and yet we never have had a catastrophic outcome. On a national level, giving up VBAC would mean performing an additional 100,000 cesareans every year**. It is unlikely this huge number of operations could be performed without many serious complications and perhaps even some matemal deaths.

** WebWife note: 100,000 additional CS equals between 32 and 100 additional maternal deaths [Liliford, et al, Gabbe obstetrical text, 1991] At a 1% rupture rate as cited by Dr. Flamm, an additional 1000 uterine ruptures would occur if VBAC was not permitted. If 50% are "catastrophic" to the neonate as suggested by Dr. Flamm, 500 babies would suffer bad outcomes at some level (prolonged NICU hospitalization through permanent neurological damage with approximately 100 deaths). A ratio of five to one has been the classical risk ratio between mothers and babies (that 5 or more babies are lost for every one mother). A return to routine repeat CS would mean that approximately a 3:1 to 1:1 ratio of maternal causalities.

And additional aspect of this controversy, not mentioned by Dr. Flamm, is the association with uterine rupture and the use of pitocin augmentation during the labor. Of the 4 VBAC ruptures that occurred in the greater Bay Area, 3 were on pitocin.

***also see articles about Vancomycin-resistant pathogens and other hospital-acquired infections by mothers and babies to assess risks of hospitalization and surgical delivery.

If a return to the days of "once a cesarean, always a cesarean" is not the answer, what is? I believe it is a more cautious approach to VBAC. in 99% of cases, labor after previous cesarean is much like any other labor. But we must never forget that in approximately 1% of cases the uterus will rupture. To avoid catastrophes, we must always be ready to move quickly. A prolonged deceleration of the FHR is often the first warning sign of uterine rupture. [19] If this occurs, every second counts. A large study" on uterine rupture found that no infants had significant perinatal morbidity when delivered within 17 minutes of the onset of a prolonged deceleration. The conclusion seems to be that if a prolonged deceleration to 90 beats per minnute or less lasting more than 1 minute occurs during a trial of labor, you should perform an immediate cesarean operation. Do not waste time performing an ultrasound examination or counting instruments. In many such cases you will find no uterine rupture, but in other cases you will have saved a baby's life.

The Appropriate-Hospital Controversy

The literature documents thousands on thousands of VBACs with almost uniformly good outcomes, but most of these labors took place in hospitals in which obstetricians, anesthesiologists, and operating room nurses were immediately available."' In some settings, it may not be possible to perform a "crash" cesarean within 10-15 minutes of the onset of an ominous fetal monitor pattern. It is tempting for those of us who practice in large medical centers to conclude that hospitals without round-the-clock in-house cesarean teams are not appropriate for VBAC. However, that logic also would lead to the conclusion that such hospitals are not equipped to handle any obstetric cases. Sudden obstetric emergencies such as placental abruption, cord prolapse, and unexplained severe FHR decelerations can occur in parturients with no previous cesarean, and the incidence of each of these complications is similar to the incidence of uterine rupture.

Therefore, although it may be reasonable to refer VBAC patients to centers with immediate cesarean capabilities, it does not seem logical to mandate such referrals. This is especially true in rural areas where a patient might opt for home birth if her only alternative involved extensive travel to an urban medical center. This also raises the question of whether it is appropriate to single out VBAC patients to sign a document acknowledging that it might not be possible to perform a cesarean quickly enough to prevent fetal brain damage, Should all women at hospitals without full-time in-house cesarean teams be given this same informed consent and be offered the opporturiitv to seek obstetric care elsewhere? A more reasonable approach would be to strive to improve response times for emergency cesarean operations at all hospitals. This will not be an easy task in some settings, but there are few more worthy goals.


As we approach the end of the 20th century, the definition of the "appropriate" cesarean rate remains elusive and the place of VBAC remains controversial. The issue of what constitutes appropriate informed consent for VBAC continues to be debated. Discussion of even a small risk of potential fetal brain damage certainly will dissuade most women from attempting VBAC. Is this good medicine or just a misguided attempt at risk management? Is it appropriate to inform patients of each and every conceivable risk of a given treatment option? Where do we draw the line? The risk of an infant being neurologically impaired when delivered by cesarean performed to salvage a fetus at 25 weeks' gestation is at least a hundred times greater than the risk faced by a term infant in a woman attempting a VBAC. Yet, we do not insist that women with extremely premature infants sign consent forms stating that if they decide to proceed with a cesarean they may end up with a neurologically impaired child. Clearly, there are risks to VBAC, but the aforementioned consent forms vastly overstate them.

A woman with a prior cesarean is at increased risk regardless of her mode of birth, and eliminating VBAC will not eliminate the risks. Vigilance with respect to primary cesarean delivery is the only way to avoid this dilemma. The young woman delivered by primary cesarean for "lack of progress" in the latent phase of labor will have a permanently scarred uterus and will be at some increased risk during any and all future pregnancies.

For the moment, at least in some parts of the country, the pendulum seems to be swinging back toward routine repeat cesarean. This may cause the national cesarean rate, which has been stable at approximately 22% for several years, to once again begin to climb. As the next century comes to a close, our descendants will no doubt look back at our current cesarean rates and smile. The question is, Will they find our current rates ridiculously high or ridiculously low?

All 19 References immediately follow picture and Dr. Flamm's address
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Bruce L. Flamm, MD
Department of Obstetrics and Gynecology
Kaiser Permanente Medical Center
10800 Magnolia Avenue
Riverside, CA 92505

Received February 21, 1997.
Received in revised form April 16, 1997,
Accepted April 24, 1997.

1. Cragin EB. Conservatism in obstetrics. NY Med i 1916;104:1-3.

2. Kerr JM. The technique of cesarean section with special referenceto the lower uterine segment incision. Am J Obstct Gynecol 1926,12:729 31

3. Cosgrove RA. Management of pregnancy and delivery following cesarean section. JAMA 1951;145:884-8.

4. Riva HL, Teich JC. Vaginal delivery after previous cesarean section. Am Journal Obstet Gynecol 1961;81:501-10.

5. Gibbs CE. Planned vaginal delivery following cesarean section. Clin Obstet Gvnecol 1980;23:508-15-

6. Lavin J, Steph ens R, Miodoviiik M, Barden T. Vaginal deliverv in patients with a prior cesarean section, Am j Obsttt Gynecol 1982;59:135-48.

7. Flanun BL. Vaginal birth after cesarean: Controversies old and new. Clin Obstet Gynecol 1985;28:735-43.

8. Flamm BL, Newman LA, Thomas Sj, Fallon D, Yoshida MM. Vaginal birth after cesarean delivery: Results of a 5-year multicenter collaborative study. Obstet Gynecol 1990;76:750-4.

9. Phelan JP, Clark SI-, Diaz F, Paul RH. Vaginal birth after cesarean. Am j Obstet Gynecol 1987;157:1510-5.

10. Ventura Sj, Martin JA, Taffel SM, Mathews Tj, Clarke SC. Advance report of final natality statistics, 1993. Monthly vital statistics report; vol. 44, no. 3. Hyattsville, Maryland: National Center for Health Statistics, 1995:72.

11. Jones RO, Nagashima AW, Hartnett-Goodman MM, Goodlin RC. Rupture of low transverse cesarean scars during trial of labor. Obstet Gynecol 1991;77:815-7.

12. Scott JR. Mandatory trial of labor after cesarean delivery; An alternative viewpoint. Obstet Gynecol 1991;77:811-4.

13. Pitkin RM- Once a cesarean? [editorial] Obstet Gynecol 1991;77:939.

14. Flanun BL, Goings JR, Yunbao L, Wolde-Tsadik G. Elective repeat cesarean delivery versus trial of labor: A prospective multicenter study. Obstet Gynecol 1994;83:927-32.

15. McMahon Mj, Luther ER, Bowes WA, Olshan AF. Comparison of trial of labor with an elective second cesarean section. N Engl J Med 1996;335:689-95.

16. Chervenak FA, McCullugh LB. An ethically justified algorithm for offering, recommending, and performing cesarean delivery and its application in managed care practice. Obstet Gynecol 1996;87: 302-5.

17. American College of Obstetricians and Gynecologists. Vaginal delivery after a previous cesarean birth. ACOG committee opinion no. 143. Washington, DC: ACOG, 1994.

18. Flamm BL. The patient who demands cesarean delivery. In: Quilligan EJ, Flamm BL, eds. Cesarean section: Guidelines for appropriate utilization. New York: Springer-Verlag, 1995:207-21.

19. Leung AS, Leung EK, Paul RH. Uterine rupture after previous cesarean delivery: Maternal and fetal consequences. Am Journal Obstet Gynecol 1993;169:945-50.

Copyright @ 1997 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc.

Flamm Cesarean Controversy