Who’s at Risk of a Bad Outcome with Trial of Labor after Cesarean?
How should childbearing women with a history of cesarean be counseled about the optimal mode of delivery with their current pregnancy?
The American College of Obstetricians and Gynecologists has moved back and forth on its official position over the past 15 years. veering sharply toward a conservative philosophy after a single paper (Lydon-Rochelle et al, cited below) outlined the dangers of uterine rupture with a trial of labor. Its current Position Paper on Vaginal Birth after Cesarean leans toward a more tolerant position of labor trial as far as most women are concerned, undoubtedly in reaction to the soaring cesarean rate over this period of time, the dissatisfaction of women who want to have a vaginal birth if possible and are thwarted by hospitals and obstetricians who refuse to allow them a trial of labor (called a TOLAC in the obstetric jargon), and the rising rate of maternal morbidity and mortality in the US related to cesarean delivery. The American College of Nurse-Midwives Position Statement on vaginal birth after cesarean states that “All women who have experienced cesarean birth have the right to safe and accessible options when giving birth in subsequent pregnancies;” and that CNMs/CMs are qualified to “provide education, informed consent, and risk assessment” for women with previous cesarean section, and to “manage antepartum and intrapartum care for women who are candidates for a TOLAC including establishing appropriate arrangements for medical consultation and emergency care if necessary.” The American Academy of Family Physicians has excellent although somewhat dated (2005) guidelines that include grade levels referring to the research evidence used to make a decision on each guideline. Interestingly, the guidelines state that “TOLAC should not be restricted to facilities with surgical teams present throughout labor because there is no evidence that these additional resources result in improved outcomes. A management plan for uterine rupture and other potential emergencies requiring rapid cesarean section should be available and documented for each woman undergoing TOLAC. This recommendation differs from the current American College of Obstetrics and Gynecology (ACOG) guidelines and policy.” Neither the ACNM nor the AAFM positions prohibit trials of labor in facilities without the availability of immediate surgical capacity. What remains unstated is whether this includes out-of-hospital settings, as long as they adhere to the need for a “management plan for uterine rupture and other potential emergencies requiring rapid cesarean section.”
In the December, 2001 issue of Birth (1), Bruce Flamm, an obstetrician and highly respected VBAC researcher in California, wrote an excellent commentary on the article in the New England Journal of Medicine (2) by Lydon-Rochelle and colleagues about the risk of uterine rupture during labor among women with a prior cesarean delivery. Every midwife should read Dr. Flamm’s commentary in order to rebut the serious and far-reaching conclusions promulgated in the NEJM article and to present their patients with a balanced view of the benefits and risks of a trial of labor after cesarean. As Dr. Flamm points out, Lydon-Rochelle used birth certificates and hospital discharge data to retrospectively investigate the risk of uterine rupture. “Because of the study’s methodology, there was obviously no way for the authors to know if they were dealing with uterine ruptures, incidental dehiscences, or even coding errors.” No actual hospital charts were actually reviewed in the study, and flaws in the use of ICD codes are apparent on perusing tables in Lydon-Rochelle’s article. A large number of women in the trial-of-labor groups were coded as having breech presentations or placenta previas; as Dr. Flamm says, “It is beyong comprehension that 44 women with previous cesarean delivery had spontaneous or induced trial of labor despite the diagnosis of placenta previa in the current pregnancy.” If such glaring errors in the study methodology exist, what is the likelihood that many other errors or inaccuracies also exist, some of which could invalidate the conclusions of the study? For the results of this study to be used to restrict women’s options for labor and birth after a previous cesarean, without considering other, stronger data about morbidity and mortality for mothers and babies, would be a mistake for clinicians and a shame for women seeking VBAC. Certainly, the available data needs to be considered carefully, better studies need to be done, and professional guidelines need to be written and disseminated to help everyone make an informed choice.
(1) Flamm B. Vaginal Birth After Cesarean and the New England Journal of Medicine: A Strange Controversy. Birth 28:4, December 2001, pp. 276-9.
(2) Lydon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of Uterine Rupture During Labor Among Women with a Prior Cesarean Delivery. New England Journal of Medicine 345, July 5, 2001, pp. 3-8.
As we all know, conclusions from research studies both good and bad have been used to push an agenda, and there is currently an agenda on the part of some in the obstetric profession to promote elective repeat cesarean as the option of choice for women. On the other hand, there are obstetric researchers and clinicians who are disturbed by this movement, and are working to provide the necessary research and professional guidelines that will help all of us, providers and women alike, to make an informed choice about this very important decision. Presented here are summaries of some recent research articles on trial of labor and vaginal birth after cesarean that may be helpful in assessing risk for an individual woman. I found the abstracts for these studies at PubMed. To find other relevant articles, visit PubMed at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?SUBMIT=y.
Bujold E, Bujold C, Hamilton EF, Harel F, Gauthier RJ. The Impact of a Single-Layer or Double-Layer Closure on Uterine Rupture. American Journal of Obstetrics & Gynecology 186(6), June 2002, pp.1326-30. The authors, from the Department of Obstetrics and Gynecology, Hopital Ste-Justine and Universite de Montreal, Quebec, Canada, measured the impact of a single-layer or double-layer closure on uterine rupture at subsequent delivery. They used an observational cohort study of all women undergoing a trial of labor from 1988 to 2000 in a tertiary care center, after a single low transverse cesarean delivery. Factors most highly associated with uterine rupture were identified. Of the 2142 women who met the study criteria, 1980 (92.4%) had maternal records and original operative reports reviewed. After adjustments were made for confounding variables, the odds ratio for uterine rupture in women with a single-layer closure was 3.95 (95% CI, 1.35-11.49). The authors concluded that a single-layer closure of the previous lower segment incision was the most influential factor and was associated with a 4-fold increase in the risk of uterine rupture compared with a double-layer closure.
Shipp TD, Zelop C, Repke JT, Cohen A, Caughey AB, Lieberman E The Association of Maternal Age and Symptomatic Uterine Rupture During a Trial of Labor after Prior Cesarean Delivery. Obstetrics & Gynecology 99(4), April 2002, pp. 585-8. The authors, from the Department of Obstetrics and Gynecology, Brigham and Women’s Hospital, Harvard Medical School in Boston, asked whether maternal age is associated with a symptomatic uterine rupture during a trial of labor after prior cesarean delivery.They retrospectively reviewed the medical records of all patients undergoing a trial of labor after prior cesarean delivery over a 12-year period, analyzing the labors of women with one prior cesarean and no prior vaginal deliveries. The uterine rupture rate was determined with respect to maternal age. Multiple logistic regression was used to control for potential confounding variables. Overall, 32 (1.1%) uterine ruptures occurred among 3015 women. For women younger than 30 years, the risk of uterine rupture was 0.5%, and for those women aged at least 30 years, the risk of uterine rupture was 1.4% (P =.02). Controlling for birth weight, induction, augmentation, and interdelivery interval, the odds ratio for symptomatic uterine rupture for women aged at least 30 years compared with those less than 30 years was 3.2 (95% confidence interval 1.2, 8.4). They found that women aged 30 years or older have a greater risk of uterine rupture as compared with women younger than 30 years.
Lieberman E. Risk Factors for Uterine Rupture During a Trial of Labor after Cesarean.
Clinics of Obstetrics & Gynecology 44(3), September 2001, pp. 609-21. The author, from the Center for Perinatal Research, Department of Obstetrics and Gynecology, Brigham and Women’s Hospital, Harvard Medical School, reviewed the current literature for risk factors for uterine rupture. Whereas the overall risk of rupture is 1%, the author’s review demonstrates that there is considerable variation of that risk. More than one previous scar, induction of labor, a short interdelivery interval, or a history of postpartum fever during a previous cesarean may increase the risk of a uterine rupture during a trial of labor. However, there does not appear to be an increase in risk associated with low-vertical scars, and a previous vaginal delivery may be somewhat protective. The author hopes that further delineation of the factors that increase the risk of uterine rupture will permit better prediction of individualized risk and identification of women for whom attempting a vaginal delivery after cesarean represents a safe option.
Zelop CM, Shipp TD, Repke JT, Cohen A, Lieberman E. Outcomes of Trial of Labor Following Previous Cesarean Delivery Among Women with Fetuses Weighing >4000 g. American Journal of Obstetrics & Gynecology 185(4), October 2001, pp. 903-5. The authors, from the Department of Obstetrics and Gynecology, Lenox Hill Hospital, New York City, compared outcomes at term of a trial of labor in women with previous cesarean delivery who delivered neonates weighing > 4000 g versus women with those weighing < or = 4000 g. They reviewed medical records for all women undergoing a trial of labor after prior cesarean delivery during a 12-year period. The analysis was limited to women at term with one prior cesarean and no other deliveries. The rates of cesarean delivery and symptomatic uterine rupture for women with infants weighing > 4000 g were compared to the rates for women with infants weighing < or = 4000 g. Of 2749 women, 13% (365) had infants with birth weights > 4000 g. Cesarean delivery rate associated with birth weights < or = 4000 g was 29% versus 40% for those with birth weights > 4000 g (P = .001). The authors found that birth weight > 4000 g was associated with a 1.7-fold increase in risk of cesarean delivery (95% CI, 1.3-2.2). The rate of uterine rupture for women with infants weighing < or = 4000 g was 1.0% versus a 1.6% rate for those with infants weighing > 4000 g (P = .24). Although the logistic regression analysis revealed a somewhat higher rate of uterine rupture associated with birth weights of > 4000 g (adjusted OR, 1.6; 95% CI, 0.7-4.1), this difference was not statistically significant. The rate of uterine rupture was 2.4% for women with infants weighing > 4250 g, but this rate did not differ significantly from the rate of uterine rupture associated with birth weights < or = 4250 g (P = .1). The authors concluded that a trial of labor after previous cesarean delivery may be a reasonable clinical option for pregnant women with suspected birth weights of > 4000 g, given that the rate of uterine rupture associated with these weights does not appear to be substantially increased when compared to lower birth weights. However, some caution may apply when considering a trial of labor in women with infants weighing > 4250 g. In these women with infants weighing > 4000 g, the likelihood of successful vaginal delivery, although lower than for neonates weighing < or = 4000 g, is still 60%.
Bujold E, Gauthier RJ. Should We Allow a Trial of Labor after a Previous Cesarean for Dystocia in the Second Stage of Labor? Obstetrics & Gynecology 98(4), October 2001, pp. 652-5. The authors, from the Department of Obstetrics and Gynecology, Hopital Ste-Justine and Universite de Montreal, Montreal, Quebec, Canada, estimated the rate of successful vaginal birth including operative vaginal delivery in patients with a previous cesarean for cephalopelvic disproportion in the second stage of labor. They looked at data from all patients who underwent trial of labor after a previous cesarean between 1990 and 2000 at their tertiary care institution. Medical records were reviewed and data were collected for the following variables: indication for the previous cesarean, birth weight and cervical dilatation at previous cesarean delivery, as well as the mode of delivery (spontaneous, vacuum, forceps, cesarean) and the birth weight for the subsequent pregnancy. There were 2002 patients included in the study. Two hundred fourteen (11%) had their previous cesarean for dystocia in the second stage of labor, 654 (33%) for dystocia in the first stage of labor, and 1134 (57%) for other indications. The vaginal birth after cesarean success rate was 75.2% (P = .015 vs other indications), 65.6% (P < .001 vs other indications), and 82.5%, respectively. The rate of operative vaginal delivery was 15%, 12%, and 10% (P = .109). The authors concluded that a trial of labor is reasonable in women whose previous cesarean was for dystocia in the second stage of labor. In their series, patients who underwent a trial of labor after a previous cesarean for dystocia in the second stage had 75.2% (95% confidence interval 69.5, 81.0) chance of achieving vaginal delivery.
Zelop CM, Shipp TD, Repke JT, Cohen A, Lieberman E. Effect of Previous Vaginal Delivery on the Risk of Uterine Rupture During a Subsequent Trial of Labor. American Journal of Obstetrics & Gynecology 183(5), November 2000, pp.1184-6. The authors, from the Department of Obstetrics and Gynecology, Lenox Hill Hospital, New York City, examined the effect of prior vaginal delivery on the risk of uterine rupture in pregnant women undergoing a trial of labor after prior cesarean delivery. The medical records of all pregnant women with a history of cesarean delivery who attempted a trial of labor during a 12-year period at a single center were reviewed. For the current analysis, the study population was limited to term pregnancies. The effect of previous vaginal delivery on the risk of uterine rupture during a subsequent trial of labor was evaluated. Separate analyses were performed for women with a single previous cesarean delivery and for those with >1 prior cesarean delivery. For each of these subgroups, the rate of uterine rupture among women who had > or =1 prior vaginal delivery was compared with the rate among women with no prior vaginal delivery. Of 3783 women with 1 prior scar, 1021 (27.0%) also had > or =1 prior vaginal delivery. During a subsequent trial of labor, the rate of uterine rupture was 1.1% among pregnant women without prior vaginal delivery and 0.2% among pregnant women with prior vaginal delivery (P =.01). Logistic regression analysis controlling for duration of labor, induction, birth weight, maternal age, year of birth, epidural analgesia, and oxytocin augmentation indicated that, among women with a single scar, those with a prior vaginal delivery had a risk of uterine rupture that was one fifth that of women without a previous vaginal delivery (odds ratio, 0.2; 95% confidence interval, 0.04-0.8). In the group of 143 pregnant women with >1 previous cesarean delivery, women with a prior vaginal delivery had a somewhat lower risk of uterine rupture (3.9% vs 2.5%; adjusted odds ratio, 0.6; 95% confidence interval, 0.01-6.7). This difference was not statistically significant. The authors concluded that, among women with 1 prior cesarean delivery undergoing a subsequent trial of labor, those with a prior vaginal delivery were at substantially lower risk of uterine rupture than women without a previous vaginal delivery.
Sims EJ, Newman RB, Hulsey TC. Vaginal birth after cesarean: to induce or not to induce. American Journal of Obstetrics & Gynecology 184(6), May 2001, pp. 1122-4. These authors, from the Department of Obstetrics and Gynecology, Medical University of South Carolina at Charleston studied the impact of labor induction on both the success and safety of a trial of labor in women who are candidates for vaginal birth after cesarean. They performed a prospective observational analysis of 505 women consecutively presenting for delivery with a prior cesarean (September 1997-December 1999), of whom 236 (46.7%) underwent trial of labor. The following three cohorts were established: (1) repeat cesarean without trial of labor (n = 269), (2) spontaneous trial of labor (n = 179), and (3) induced trial of labor (n = 57). The vaginal delivery rate was significantly higher (77.1% vs 57.9%) in the spontaneous labor group compared with the induced labor group (odds ratio, 2.45; 95% confidence interval, 1.24-4.82; P =.008). Uterine scar separation occurred more frequently in the induced labor group (7%) than in the elective repeat cesarean group (1.5%) (odds ratio, 0.20; 95% confidence interval, 0.04-0.99; P =.034). They concluded that induction of labor in women attempting vaginal birth after cesarean is associated with a significantly reduced rate of successful vaginal delivery and an increased risk of serious maternal morbidity.
Zelop CM, Shipp TD, Cohen A, Repke JT, Lieberman E. Trial of Labor after 40 Weeks’ Gestation in Women with Prior Cesarean. Obstetrics & Gynecology 97(3), March 2001, pp. 391-3. The authors, from the Department of Obstetrics and Gynecology, Lenox Hill Hospital, New York City, compared outcomes in women with prior cesareans delivering at or before 40 weeks’ gestation with those delivering after 40 weeks. They reviewed labor outcomes over 12 years at one institution for women with one prior cesarean and no other deliveries who had a trial of labor at term. They analyzed the rates of symptomatic uterine rupture and cesarean for term deliveries before or after 40 weeks and stratified for spontaneous and induced labor. They concluded that risk of uterine rupture does not increase substantially after 40 weeks but is increased with induction of labor regardless of gestational age. Because spontaneous labor after 40 weeks is associated with a cesarean rate similar to that following induced labor before 40 weeks, awaiting spontaneous labor after 40 weeks does not decrease the likelihood of successful vaginal delivery.
Callahan C, Chescheir N, Steiner BD. Safety and Efficacy of Attempted Vaginal Birth after Cesarean beyond the Estimated Date of Delivery. Journal of Reproductive Medicine 44(7), July 1999, pp. 606-10. These authors, from the Department of Obstetrics and Gynecology, University of North Carolina School of Medicine at Chapel Hill, sought to provide data regarding safety and efficacy for women attempting a trial of labor following earlier cesarean birth who have reached their due date. A computerized data base was analyzed to identify women who were at or beyond 40 weeks of gestation between January 1, 1995, and March 31, 1996. Ninety women attempted vaginal birth after cesarean (VBAC) during the study period; 90 controls were matched for age, race and parity. Delivery route and complications were outcome variables identified. The rate of successful VBAC was 65.6% as compared to the 94.4% vaginal delivery rate among women who had not had a prior cesarean (P < .0001). Among women attempting VBAC, 62% of those who had no prior vaginal births successfully delivered vaginally, while 82% of women with one prior vaginal birth delivered vaginally (P < .0001). Women of greater parity were more successful at a trial of labor. Infectious morbidity was more common among women attempting VBAC than among those with no prior cesarean. The patient and her family can be reassured that passing her due date does not alter the efficacy or safety of a trial of labor. No change in counseling is warranted simply due to the completion of 40 weeks’ gestation.