Uterine Rupture During VBAC Trial Of Labor: Risk Factors and Fetal Response

Nancy O'Brien-Abel, RNC, MN


J Midwifery Womens Health. 2003;48(4) 

In This Article

Abstract and Introduction


For the woman with a prior uterine scar, neither repeat elective cesarean birth nor vaginal birth after cesarean birth (VBAC) trial of labor (TOL) is risk-free. When VBAC-TOL is successful, it is associated with less morbidity than repeat cesarean birth. However, when VBAC-TOL fails due to uterine rupture, severe consequences often ensue. The challenge for clinicians today is to provide women who desire TOL after cesarean birth, a more individualized risk assessment of uterine rupture, thereby enhancing success and optimizing outcome. This article examines major risk factors for uterine rupture during VBAC-TOL. In addition, fetal response to uterine rupture and neonatal outcomes are reviewed.


In 1980, the U.S. National Institute of Child Health and Human Development (NICHHD) cosponsored a conference on cesarean childbirth with the National Center for Health Care Technology and concluded that vaginal birth after cesarean section (VBAC) was an appropriate option by which to decrease the increasing cesarean section rates.[1] Widespread interest in VBAC trial of labor (TOL) ensued, with clinical research demonstrating its relative safety.[2,3,4,5] Both obstetric care providers and women desiring an alternative to cesarean birth, as well as government and private insurance company payers, enthusiastically embraced VBAC-TOL. As a result, the number of women who had a successful VBAC in the United States increased dramatically from 3.4 per 100 women in 1980 to a peak rate of 28.3 per 100 women in 1996.[6,7]

In recent years, however, renewed controversy about the relative safety of VBAC-TOL has resulted in a rapid decline in the number of women who experience VBAC, falling from 28.3 per 100 women in 1996 to 16.4 per 100 in 2001, a 42% decrease (Figure 1).[8] Attention has focused primarily on symptomatic uterine rupture, a potentially catastrophic event, which can have serious consequences to mother and fetus. Although the overall estimated rate of uterine rupture is less than 1%, the incidence varies significantly depending on the presence of specific risk factors.[9,10,11,12] Concerns related to uterine rupture have prompted the American College of Obstetricians and Gynecologists (ACOG) to recommend that a physician be "immediately available throughout active labor, capable of monitoring labor and performing an emergency cesarean delivery"[13] when women undergo VBAC-TOL.

Figure 1.

Total cesarean and vaginal births after previous cesarean (VBAC) rate: United States, 1970 to 2001.[6,7,8]

Neither repeat cesarean birth nor TOL after cesarean is risk-free for women with a prior uterine scar. When VBAC-TOL is successful, it is associated with less morbidity than repeat cesarean birth.[2,3,4,5,9,13] However, when VBAC-TOL results in uterine rupture, neonatal death or permanent neonatal injury can occur even in facilities with immediate access to cesarean birth.[14,15,16,17]

The challenge for clinicians today is to provide women, who desire VBAC-TOL, a more individualized risk assessment of uterine rupture, thereby enhancing success and optimizing outcome. A woman and her health care provider must evaluate the following: 1) risk of complications associated with VBAC-TOL versus repeat elective cesarean birth, 2) capabilities of the birth facility, 3) personal choice, and 4) the probable success rate of VBAC-TOL. Recent research has better defined factors that influence probable success of VBAC.[18,19,20,21,22] This article addresses uterine rupture, the major complication that can occur during VBAC-TOL, and the subsequent fetal response and neonatal outcome when uterine rupture occurs.

A literature search was conducted in MEDLINE and COCHRANE databases using the following search terms: vaginal birth after cesarean, TOL, uterine rupture, risk factors, fetal heart rate, neonatal outcome. A Boolean search operator was used throughout (AND), and the search was performed in "all fields" mode. Only articles published in English since 1990 were included. Additional studies were identified under related articles. The studies presented are not exhaustive, but they represent those that have the greatest significance for clinical practice. Earlier published works can be found in extensive reviews by both Lavin et al.[23] and Lieberman.[24]


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