Our data indicate that the risk for uterine rupture is not significantly increased in women with multiple prior cesarean deliveries undergoing a trial of labor when compared with those with a single prior operation. The risks of other adverse maternal events (hysterectomy and transfusion) is increased in women with multiple prior cesarean deliveries, but the absolute level of these risks is small.
Our study also demonstrates that perinatal outcomes for this population are comparable to those observed in women with one prior cesarean delivery attempting VBAC. This information is important for counseling women regarding their options for childbirth after multiple prior cesarean deliveries.
There are a few large-scale studies addressing safety and efficacy after trial of labor after multiple prior cesarean deliveries.4–6 Previous studies have been primarily retrospective, and most are within single institutions encompassing long study periods.4,6–8 Our study is unique in its large-scale, multicenter, prospective design with trained obstetric research staff using standardized definitions.3 In designing this study, we specifically planned for a sufficient sample size to address the question of whether multiple prior cesarean deliveries are associated with an increased rate of uterine rupture in women undergoing trial of labor.
Our report provides a large-scale, prospective comparison of maternal outcomes in women with multiple prior operations undergoing trial of labor versus those having elective repeat cesarean. This comparison addresses the clinically relevant question as to the preferred mode of delivery for this population of women. Our study and the work of Macones and colleagues demonstrate that uterine rupture is the complication with the greatest risk attributable to trial of labor. Our finding of an increased risk for an adjusted composite of maternal morbidity with trial of labor (OR 1.41) confirms Macones’ observation (OR 2.26).6 Both studies thus reveal a relatively low level of increased risk that will likely be acceptable to many women considering VBAC. Although our study also provides perinatal outcome data demonstrating no apparent increased risk with trial of labor compared with elective repeat cesarean delivery after multiple prior cesareans, we recognize that the population size is insufficient to address differences in these outcomes. It is, however, likely that a larger study population would demonstrate a small but increased risk for adverse perinatal outcomes in women undergoing trial of labor as we have demonstrated in the combined cohort of women with single and multiple prior operations.3
We have confirmed that the majority of women with multiple prior cesarean deliveries undergoing trial of labor can expect to achieve a successful vaginal birth. Our reported success rate of 66% is, however, significantly lower than for women with one prior cesarean delivery (73%). This difference has been consistently reported in other studies.4,5 This finding does contrast with Macones’ observation of similar success rates (75.5% versus 74.6%) between study groups. Both our study and Macones’ analysis reveal high rates of prior vaginal delivery in women with multiple prior cesarean delivery attempting trial of labor, yet these rates were not higher than in women with single prior operation. It is possible that our finding, and that of others, of lower VBAC success with multiple prior cesarean deliveries may be explained by differences in study population characteristics that affect labor success.10
Our study does have several limitations. Women with multiple prior cesarean deliveries who undergo counseling and then elect a trial of labor have characteristics that are different from both women with a single prior operation and those who elect a repeat operation. We attempted to control for these differences in our analysis, but different approaches to labor management in particular are likely to be present among comparison groups. Our study does not provide long-term outcome data, which is particularly relevant for women undergoing multiple repeat operations who have the associated risk for hemorrhage from accreta and hysterectomy. We also recognize that our data collection process did not provide information regarding certain potential risk factors associated with uterine rupture, such as prior uterine closure technique. Nonetheless, we did attempt to control for most recognized factors and, in doing so, confirmed an association between oxytocin augmentation and induction with uterine rupture as well as the protective effect of prior vaginal delivery.3,11
In summary, it appears that any increased risk for uterine rupture in women with multiple prior cesarean deliveries attempting VBAC must be statistically small. As with women who have a single prior cesarean, this risk may be modified by clinical factors such as the need for induction and history of vaginal delivery. However, a requirement that a history of vaginal delivery be present in women with multiple prior cesarean deliveries to be considered candidates for trial of labor seems unwarranted given the apparent level of risk for uterine rupture and adverse outcomes in this population. Moreover, a comparison of outcomes after trial of labor in women with multiple prior cesarean versus those undergoing elective repeat operation indicates that both options should remain available for eligible women.
1. Hamilton BE, Martin JA, Ventra S, Sutton PD, Menacher F. Births: preliminary data for 2004. Natl Vital Stat Rep 2005;54:1–17.
2. Vaginal birth after previous cesarean delivery: clinical management guidelines for obstetrician-gynecologists. ACOG Practice Bulletin No. 54. American College of Obstetricians and Gynecologists. Obstet Gynecol 2004;104:203–12.
3. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcome associated with a trial of labor after prior cesarean delivery. N Engl J Med 2004;351:2581–89.
4. Miller DA, Diaz FG, Paul RH. Vaginal birth after cesarean: a 10-year experience. Obstet Gynecol 1994;84:255–8.
5. Caughey AB, Shipp TD, Repke JT, Zelop CM, Cohen A, Lieberman E. Rate of uterine rupture during trial of labor in women with one or two prior cesarean deliveries. Am J Obstet Gynecol 1999;181:872–6.
6. Macones GA, Cahill A, Pare E, Stamilio DM, Ratcliffe S, Stevens E, et al. Obstetric outcomes in women with two prior cesarean deliveries: Is vaginal birth after cesarean delivery a viable option? Am J Obstet Gynecol 2005;192:1223–9.
7. Askura H, Myers SA. More than one previous cesarean delivery: a 5-year experience with 435 patients. Obstet Gynecol 1995;85:924–9.
8. Novas J, Myers SA, Gleicher N. Obstetric outcome of patients with more than one previous cesarean section. Am J Obstet Gynecol 1989;160:364–7.
9. Macones GA, Peipert J, Nelson DB, Odibo A, Stevens EJ, Stamilio DM, et al. Maternal complications with vaginal birth after cesarean delivery: a multicenter study. Am J Obstet Gynecol 2005;193:1656–62.
10. Landon MB, Leindecker S, Spong CY, Hauth J, Bloom S, Varner MW, et al. The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery. Am J Obstet Gynecol 2005;193:1016–23.
11. Zelop CM, Shipp TD, Repke JT, Cohen A, Caughey AB, Lieberman E. Uterine rupture during induced or augmented labor in gravid women with one prior cesarean delivery. Am J Obstet Gynecol 1999;181:882–6.
In addition to the authors, other members of the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network are as follows:
The Ohio State University, Columbus, OH: J. Iams, F. Johnson, S. Meadows, H. Walker
University of Alabama at Birmingham, Birmingham, AL: D. Rouse, A. Northen, S. Tate
University of Texas Southwestern Medical Center, Dallas, TX: K. Leveno, J. Mc Campbell, D. Bradford
University of Utah, Salt Lake City, UT: M. Belfort, F. Porter, B. Oshiro, K. Anderson, A. Guzman
University of Chicago, Chicago, IL: J. Hibbard, P. Jones, M. Ramos-Brinson, M. Moran, D. Scott
University of Pittsburgh, Pittsburgh, PA: K. Lain, M. Cotroneo, D. Fischer, M. Luce
Wake Forest University, Winston-Salem, NC: P. Meis, M. Swain, C. Moorefield, K. Lanier, L. Steele
Thomas Jefferson University, Philadelphia, PA: A. Sciscione, M. DiVito, M. Talucci, M. Pollock
Wayne State University, Detroit, MI: M. Dombrowski, G. Norman, A. Millinder, C. Sudz, B. Steffy
University of Cincinnati, Cincinnati, OH: T. Siddiqi, H. How, N. Elder
Columbia University, New York, NY: F. Malone, M. D’Alton, V. Pemberton, V. Carmona, H. Husami
Brown University, Providence, RI: H. Silver, J. Tillinghast, D. Catlow, D. Allard
Northwestern University, Chicago, IL: M. Socol, D. Gradishar, G. Mallett
University of Miami, Miami, FL: G. Burkett, J. Gilles, J. Potter, F. Doyle, S. Chandler
University of Tennessee, Memphis, TN: W. Mabie, R. Ramsey
University of Texas Health Science Center at San Antonio, San Antonio, TX: D. Conway, S. Barker, M. Rodriguez
University of North Carolina at Chapel Hill, Chapel Hill, NC: K. Moise, K. Dorman, S. Brody, J. Mitchell
University of Texas Health Science Center at Houston, Houston, TX: L. Gilstrap, M. Day, M. Kerr, E. Gildersleeve
Case Western Reserve University, Cleveland, OH: P. Catalano, C. Milluzzi, B. Silvers, C. Santori
The George Washington University Biostatistics Center, Washington, DC: S. Gilbert, H. Juliussen-Stevenson, M. Fischer
National Institute of Child Health and Human Development, Bethesda, MD: D. McNellis, K. Howell, S. Pagliaro