To determine whether an indication for cesarean delivery increases the rate of uterine rupture, women with an indicated repeat cesarean delivery were compared with women without an indication (repeat cesarean delivery with and without labor) (Table 4). Uterine rupture occurred in 7 of 6,080 (0.12%) compared with 4 of 17,714 (0.02%), respectively. Thus, an indication for cesarean delivery increased the risk of uterine rupture by a factor of 5 (odds ratio [OR] 5.1, 95% confidence interval [CI] 1.49–17.44); after controlling for multiple cesarean deliveries and for classical/T/J incision, the odds ratio was 5.98 (95% CI 1.38–30.09) (Table 5). To evaluate whether the presence of labor increased the risk of uterine rupture in women undergoing repeat cesarean delivery, women without an indication for cesarean delivery who delivered by repeat cesarean delivery with labor were compared with those who delivered by repeat cesarean delivery without labor. Uterine rupture occurred in 4 of 2,721 or 0.15% compared with 0 of 14,993, respectively (P<.01).
The presence of labor in women undergoing repeat cesarean delivery did not increase the risk of adverse neonatal outcome and hypoxic ischemic encephalopathy. This was evaluated by comparing women with repeat cesarean delivery with labor with those with repeat cesarean delivery without labor; the composite neonatal outcome was 6 (0.22%) compared with 19 (0.13%), respectively (OR 1.74, 95% CI 0.69–4.36), and there was no hypoxic ischemic encephalopathy in either group. The presence of an indication for repeat cesarean delivery increased the rate of adverse neonatal outcome and hypoxic ischemic encephalopathy. For this comparison, women with an indicated repeat cesarean delivery were compared with those delivered by cesarean delivery with and without labor; the composite was 23 (0.38%) compared with 25 (0.14%), respectively (OR 2.69, 95% CI 1.53–4.75), and hypoxic ischemic encephalopathy occurred in 3 of 6,071 (0.05%) compared with 0, respectively.
We found that the risk of uterine rupture and adverse perinatal outcome for women with a singleton term gestation and prior cesarean delivery is low, occurring in 3 per 1,000 women. Counseling for women at term with a prior cesarean delivery for risk of uterine rupture can be provided as a range from 0% to 0.74%, depending on whether they attempt a trial of labor, have an indication for repeat cesarean delivery (with or without labor), experience labor, or have a cesarean delivery without labor. In a woman at term planning a repeat cesarean delivery, the uterine rupture risk is 0.05%. Exposure to early labor and labor aborted by an indicated cesarean delivery only marginally increased the risk of uterine rupture; the greatest risk for uterine rupture occurred in women attempting vaginal delivery. For adverse composite perinatal outcome, the frequency ranges from 0.13% to 0.40% and for maternal composite complications, from 3% to 8%. Importantly, adverse perinatal outcomes such as hypoxic ischemic encephalopathy occurred in women without uterine rupture in half of the cases, and adverse maternal outcomes such as maternal death occurred more in women undergoing elective cesarean delivery without labor and without an indication.
Few uterine ruptures occurred in women with early labor and elective cesarean delivery. Thus, the risk for rupture was low with planned cesarean delivery, although some of these women may have planned to attempt a trial of labor and changed their minds. In addition, the presence of early labor did not increase the risk of adverse perinatal outcomes in this group. Women with indications for cesarean delivery overall had increased risks for uterine rupture and adverse perinatal and maternal outcomes. This may be, in part, due to the underlying nature of their indication because pregnancies complicated by abnormal presentation, placenta previa, and preeclampsia, among others, are known to have increased risks.
Available literature does not address all of the subgroups analyzed in this manuscript, but where data are available, our findings are consistent with others in the literature. In a retrospective cohort study of over 600 women, Cahill et al2 found a uterine rupture frequency of 0.40% in women attempting trial of labor and 0.06% of those undergoing an elective cesarean delivery. Their frequencies of transfusion (0.44–2.01%) are also consistent with our findings. In a meta-analysis covering studies published in 1989–1999, Mozurkewich and Hutton3 found a uterine rupture frequency of 0.39% for trial of labor compared with 0.16% for elective repeat cesarean delivery. Hibbard et al4 found a uterine rupture frequency of 0.8% for trial of labor and 0% for elective repeat cesarean delivery and a hysterectomy risk of 1% and 0%, respectively, in 1,755 women, which results are consistent with our findings. Chauhan et al,5 in their literature review of 142,075 women attempting trial of labor, found a uterine rupture frequency of 6.2 per 1,000, and Macones et al,6 in their case control study, found a uterine rupture risk of 9.8 per 1,000. Our overall finding of uterine rupture risk of 3 per 1,000 is consistent with the findings of Guise et al7 in their systematic review. In addition, our findings of more maternal deaths in women undergoing an elective cesarean without indication is consistent with the findings of Wen et al8 who found an increased risk of maternal death in a retrospective cohort study of 308,755 Canadian women over a 12-year period.
Owing to the prospective observational nature of this study, there are several limitations, including the inability to discern how many women planned to attempt a trial of labor and changed their minds and how many women who attempted a trial of labor had actually desired an elective repeat cesarean delivery but presented with advanced labor. However, even with these limitations, these data provide physicians and women with pragmatic information for counseling on the risks of uterine rupture, as well as adverse perinatal and maternal outcomes for the woman at term who have histories of prior cesarean delivery.
1. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med 2004;351:2581–9.
2. Cahill AG, Stamilio DM, Odibo AO, Peipert JF, Ratcliffe SJ, Stevens EJ, et al. Is vaginal birth after cesarean (VBAC) or elective repeat cesarean safer in women with a prior vaginal delivery? Am J Obstet Gynecol 2006;195:1143–7.
3. Mozurkewich EL, Hutton EK. Elective repeat cesarean delivery versus trial of labor: a meta-analysis of the literature from 1989 to 1999. Am J Obstet Gynecol 2000;183:1187–97.
4. Hibbard JU, Ismail MA, Wang YT, Te C, Karrison T, Ismail MA. Failed vaginal birth after a cesarean section: how risky is it? I. Maternal morbidity. Am J Obstet Gynecol 2001;184:1365–73.
5. Chauhan SP, Martin JN, Henrichs CE, Morrison JC, Magann EF. Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: a review of the literature. Am J Obstet Gynecol 2003;189:408–17.
6. 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.
7. Guise JM, Berlin M, McDonagh M, Osterweil P, Chan B, Helfand M. Safety of vaginal birth after cesarean: a systematic review Obstet Gynecol 2004;103:420–9.
8. Wen SW, Rusen ID, Walker M, Liston R, Kramer MS, Baskett T, et al. Comparison of maternal mortality and morbidity between trial of labor and elective cesarean section among women with previous cesarean delivery. Am J Obstet Gynecol 2004;191:1263–9.
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:
Ohio State University — J. Iams, F. Johnson, S. Meadows, H. Walker
University of Alabama at Birmingham — J. Hauth, A. Northen, S. Tate
University of Texas Southwestern Medical Center — S. Bloom, J. Gold, D. Bradford
University of Utah — M. Belfort, F. Porter, B. Oshiro, K. Anderson, A. Guzman
University of Chicago — J. Hibbard, P. Jones, M. Ramos-Brinson, M. Moran, D. Scott
University of Pittsburgh — S. Caritis, K. Lain, M. Cotroneo, D. Fischer, M. Luce
Wake Forest University — P. Meis, M. Swain, C. Moorefield, K. Lanier, L. Steele
Thomas Jefferson University — A. Sciscione, M. DiVito, M. Talucci, M. Pollock
Wayne State University — M. Dombrowski, G. Norman, A. Millinder, C. Sudz, B. Steffy
University of Cincinnati — T. Siddiqi, H. How, N. Elder
Columbia University — F. Malone, M. D'Alton, V. Pemberton, V. Carmona, H. Husami
Brown University — H. Silver, J. Tillinghast, D. Catlow, D. Allard
Northwestern University — M. Socol, D. Gradishar, G. Mallett
University of Miami, Miami, FL — G. Burkett, J. Gilles, J. Potter, F. Doyle, S. Chandler
University of Tennessee — W. Mabie, R. Ramsey
University of Texas at San Antonio — D. Conway, S. Barker, M. Rodriguez
University of North Carolina — K. Moise, K. Dorman, S. Brody, J. Mitchell
University of Texas at Houston — L. Gilstrap, M. Day, M. Kerr, E. Gildersleeve
Case Western Reserve University — P. Catalano, C. Milluzzi, B. Slivers, C. Santori
Vanderbilt University – Steven G. Gabbe
The George Washington University Biostatistics Center — E. Thom, H. Juliussen-Stevenson, M. Fischer
National Institute of Child Health and Human Development — D. McNellis, K. Howell, S. Pagliaro