Obstetrics & Gynecology:
Risk of Uterine Rupture and Adverse Perinatal Outcome at Term After Cesarean Delivery
Spong, Catherine Y. MD1; Landon, Mark B. MD2; Gilbert, Sharon MS, MBA3; Rouse, Dwight J. MD4; Leveno, Kenneth J. MD5; Varner, Michael W. MD6; Moawad, Atef H. MD7; Simhan, Hyagriv N. MD8; Harper, Margaret MD9; Wapner, Ronald J. MD10; Sorokin, Yoram MD11; Miodovnik, Menachem MD12; Carpenter, Marshall MD13; Peaceman, Alan M. MD14; O'Sullivan, Mary J. MD15; Sibai, Baha M. MD16; Langer, Oded MD17; Thorp, John M. MD18; Ramin, Susan M. MD19; Mercer, Brian M. MD20; for the National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network
From the 1National Institute of Child Health and Human Development, Bethesda, Maryland; the 2Department of Obstetrics and Gynecology at the Ohio State University, Columbus, Ohio; the 3George Washington University Biostatistics Center, Washington, DC; the 4Departments of Obstetrics and Gynecology at the University of Alabama at Birmingham, Birmingham, Alabama; 5University of Texas Southwestern Medical Center, Dallas, Texas; 6University of Utah, Salt Lake City, Utah; 7University of Chicago, Chicago, Illinois; 8University of Pittsburgh, Pittsburgh, Pennsylvania; 9Wake Forest University, Winston-Salem, North Carolina; 10Thomas Jefferson University, Philadelphia, Pennsylvania; 11Wayne State University, Detroit, Michigan; 12University of Cincinnati, Cincinnati, Ohio; 12Columbia University, New York, New York; 13Brown University, Providence, Rhode Island; 14Northwestern University, Chicago, Illinois; 15University of Miami, Miami, Florida; 16University of Tennessee, Memphis, Tennessee; 17University of Texas at San Antonio, San Antonio, Texas; 18University of North Carolina, Chapel Hill, North Carolina; 19University of Texas at Houston, Houston, Texas; and 20Case Western Reserve University, Cleveland, Ohio.
* For members of the NICHD MFMU Network, see the Appendix.
Supported by grants from the National Institute of Child Health and Human Development (HD21410, HD21414, HD27860, HD27861, HD27869, HD27905, HD27915, HD27917, HD34116, HD34122, HD34136, HD34208, HD34210, HD40500, HD40485, HD40544, HD40545, HD40560, HD40512, and HD36801).
The authors thank Elizabeth Thom, PhD, for protocol/data management and statistical analysis, Francee Johnson, BSN, and Julia Gold, BSN/APN, for protocol development and coordination between clinical research centers, and Sandra Meadows for data management.
Corresponding author: Catherine Y. Spong, MD, Chief, PPB, NICHD, NIH, 6100 Executive Boulevard, Room 4B03 MSC 7510, Bethesda, MD 20892; e-mail: firstname.lastname@example.org.
Financial Disclosure The authors have no potential conflicts of interest to disclose.
OBJECTIVE: Current information on the risk of uterine rupture after cesarean delivery has generally compared the risk after trial of labor to that occurring with an elective cesarean delivery without labor. Because antepartum counseling cannot account for whether a woman will develop an indication requiring a repeat cesarean delivery or whether labor will occur before scheduled cesarean delivery, the purpose of this analysis was to provide clinically useful information regarding the risks of uterine rupture and adverse perinatal outcome for women at term with a history of prior cesarean delivery.
METHODS: Women with a term singleton gestation and prior cesarean delivery were studied over 4 years at 19 centers. For this analysis, outcomes from five groups were studied: trial of labor, elective repeat with no labor, elective repeat with labor (women presenting in early labor who subsequently underwent cesarean delivery), indicated repeat with labor, and indicated repeat without labor. All cases of uterine rupture were reviewed centrally to assure accuracy of diagnosis.
RESULTS: A total of 39,117 women were studied. In term pregnant women with a prior cesarean delivery, the overall risk for uterine rupture was 0.32% (125 of 39,117), and the overall risk for serious adverse perinatal outcome (stillbirth, hypoxic ischemic encephalopathy, neonatal death) was 106 of 39,049 (0.27%). The uterine rupture risk for indicated repeat cesarean delivery (labor or without labor) was 7 of 6,080 (0.12%); the risk for elective (no indication) repeat cesarean delivery (labor or without labor) was 4 of 17,714 (0.02%). Indicated repeat cesarean delivery increased the risk of uterine rupture by a factor of 5 (odds ratio 5.1, 95% confidence interval 1.49–17.44). In the absence of an indication, the presence of labor also increased the risk of uterine rupture (4 of 2,721 [0.15%] compared with 0 of 14,993, P<.01). The highest rate of uterine rupture occurred in women undergoing trial of labor (0.74%, 114 of 15,323).
CONCLUSION: At term, the risk of uterine rupture and adverse perinatal outcome for women with a singleton and prior cesarean delivery is low regardless of mode of delivery, occurring in 3 per 1,000 women. Maternal complications occurred in 3–8% of women within the five delivery groups.
LEVEL OF EVIDENCE: II
Current information on the risk of uterine rupture after a prior cesarean delivery has, in most cases, compared the risk of uterine rupture after trial of labor to that occurring with an elective cesarean delivery (without labor). However, whether a woman will develop an indication for repeat cesarean delivery is somewhat unpredictable; for example, a malpresentation or spontaneous labor may occur, which makes antepartum counseling difficult. Previously, we evaluated the risk of uterine rupture and hypoxic ischemic encephalopathy in pregnant women with a prior cesarean delivery by comparing women who underwent a trial of labor (attempting a vaginal delivery after cesarean delivery) and women who had an elective repeat cesarean delivery without labor.1 This analysis compares two precisely defined groups that cannot be identified before the time of delivery. Two other common groups of women, those presenting in early labor who subsequently underwent cesarean delivery and those with an indicated repeat cesarean delivery, were excluded from the previous analysis.
Our findings have been interpreted to suggest that an elective cesarean delivery prevents hypoxic ischemic encephalopathy and reduces the risk of uterine rupture.1 However, counseling women is not so straightforward because women who decide they prefer an elective cesarean may enter labor and undergo cesarean delivery after experiencing uterine activity. In addition, there are no data for counseling women with an indication for repeat cesarean delivery regarding maternal and perinatal risks. The objective of this analysis was to provide clinically useful information regarding the risks of uterine rupture and adverse perinatal and maternal outcome for women at term with a prior cesarean delivery.
MATERIALS AND METHODS
This was a secondary analysis of a previously reported prospective cohort observational study conducted from 1999 to 2002 at 19 academic medical centers. Women with a singleton gestation at term and prior cesarean delivery were studied. Trained personnel collected data prospectively on all women who underwent cesarean delivery and those who attempted vaginal delivery as previously described.1 For this analysis, five groups were studied: women attempting a trial of labor, women delivering by elective (nonindicated) repeat cesarean delivery without labor, women delivering by elective (nonindicated) repeat cesarean delivery performed after the onset of labor, women delivering by indicated repeat cesarean delivery without labor, and women delivering by indicated repeat cesarean delivery with labor.
In accordance with the Maternal-Fetal Medicine Units Network procedures, the data collected underwent routine edits and audits. All cases of uterine rupture were reviewed centrally to assure accuracy of diagnosis. Uterine rupture was defined as a disruption or tear of the uterine muscle and visceral peritoneum or a separation of the uterine muscle with extension to the bladder or broad ligament, and uterine dehiscence was defined as a disruption of the uterine muscle with intact serosa.1 Adverse perinatal outcome was defined as stillbirth, hypoxic ischemic encephalopathy, and/or neonatal death. Cases of hypoxic ischemic encephalopathy were reviewed centrally.
The study was approved by the human subjects committees at each participating center. Continuous variables were compared by using the Kruskal-Wallis test, and categorical variables were compared with χ2 or Fisher exact test, where appropriate. Multiple exact logistic regression was used to adjust for multiple prior cesarean deliveries and a prior classical/T/J incision for the outcome uterine rupture. Nominal two-sided P values are reported, with statistical significance defined as P<.05, without adjustment for multiple comparisons. Analysis was performed with SAS 8 (SAS Institute Inc, Cary, NC).
A total of 39,117 women were studied (Fig. 1). Of these, 15,323 attempted a trial of labor, 14,993 had an elective (nonindicated) repeat cesarean delivery without labor, 2,721 had an elective (nonindicated) repeat cesarean delivery with labor, 5,002 had an indicated repeat cesarean delivery without labor, and 1,078 had an indicated repeat cesarean delivery with labor. The rate of successful trial of labor was 73.3% (11,226 successful vaginal births after cesarean of the 15,323 attempted). Demographic data are presented in Table 1. The most common indications for the 6,080 indicated repeat cesarean deliveries were an unknown prior incision and noncephalic presentation (Table 2). In term pregnant women with a prior cesarean delivery, the overall risk for uterine rupture was 0.32% (125 of 39,117), and the overall risk of serious adverse perinatal outcome (stillbirth, hypoxic ischemic encephalopathy, neonatal death) was 0.27% (106 of 39,049). Four uterine ruptures were associated with a prior classical incision, two in women who had an indicated repeat cesarean delivery with labor, one in a patient with an elective repeat cesarean delivery with labor, and one in the trial of labor group who either presented in advanced labor or refused repeat cesarean delivery.
Adverse perinatal outcome occurred in 0.13–0.40% within the five delivery groups (Table 3). Of the 15 cases of hypoxic ischemic encephalopathy, 12 were delivered after trial of labor, and three were indicated repeat cesarean deliveries without labor. Eight of the 15 were associated with uterine rupture, seven of these were after trial of labor, and one was an indicated repeat cesarean delivery without labor. Of the antepartum stillbirths, six had known congenital anomalies, four of these attempted trial of labor, one had an elective repeat with no labor, and one had an indicated cesarean delivery with labor. The gestational age range of the stillbirths was 37–42 weeks. Maternal complications occurred in 3–8% of pregnancies within the five delivery groups (Table 4). Of the six maternal deaths, none were associated with uterine rupture, five were elective repeat cesarean deliveries, and one was after a trial of labor. Of those delivered by elective repeat cesarean delivery, three maternal deaths resulted from amniotic fluid embolism, one from hemorrhage, and one from an anesthetic complication (subdural hemorrhage). The maternal death associated with trial of labor resulted from hemorrhage.
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
© 2007 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
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