VBAC info

[mrsjenrn]

Sorry this took so long, and I will be adding things here and there. Of course I highly recommend everyone has a VBAC, but it is a personal choice that every family needs to take into consideration. The medical community does a HORRIBLE job explaining the risks and benefits, and they love to just gloss over the complications of a RCS, especially multiple c sections. I will start with some book recommendations.

1. Ina May's Guide to Childbirth (Ina May Gaskin)
2. The VBAC Companion (Diana Korte)
3. Birth After Cesarean (Bruce L. Flamm, MD)
4. The Thinking Woman's Guide to a Better Birth (Henci Goer)
5. The VBAC Handbook (Helen Churchill/Wendy Sage)
6. Natural Childbirth After Cesarean (Karis Crawford/Johanne Walters)
7. Open Season (Nancy Cohen) **emotional read**
8. Silent Knife (Nancy Cohen/Lois Estner) **emotional read**
9. Your Best Birth (Ricki Lake/Abby Epstein)
10. Pushed (Jennifer Block)
11. The Doula Guide to Birth (Anada Lowe/Rachel Zimmerman)
12. Birthing From Within

[mrsjenrn]

From the American College of Obstetrics and Gynecology (ACOG):

Ob Gyns Issue Less Restrictive VBAC Guidelines
July 21, 2010
Washington, DC -- Attempting a vaginal birth after cesarean (VBAC) is a safe and appropriate choice for most women who have had a prior cesarean delivery, including for some women who have had two previous cesareans, according to guidelines released today by The American College of Obstetricians and Gynecologists.
The cesarean delivery rate in the US increased dramatically over the past four decades, from 5% in 1970 to over 31% in 2007. Before 1970, the standard practice was to perform a repeat cesarean after a prior cesarean birth. During the 1970s, as women achieved successful VBACs, it became viewed as a reasonable option for some women. Over time, the VBAC rate increased from just over 5% in 1985 to 28% by 1996, but then began a steady decline. By 2006, the VBAC rate fell to 8.5%, a decrease that reflects the restrictions that some hospitals and insurers placed on trial of labor after cesarean (TOLAC) as well as decisions by patients when presented with the risks and benefits.
"The current cesarean rate is undeniably high and absolutely concerns us as ob-gyns," said Richard N. Waldman, MD, president of The College. "These VBAC guidelines emphasize the need for thorough counseling of benefits and risks, shared patient-doctor decision making, and the importance of patient autonomy. Moving forward, we need to work collaboratively with our patients and our colleagues, hospitals, and insurers to swing the pendulum back to fewer cesareans and a more reasonable VBAC rate."
In keeping with past recommendations, most women with one previous cesarean delivery with a low-transverse incision are candidates for and should be counseled about VBAC and offered a TOLAC. In addition, "The College guidelines now clearly say that women with two previous low-transverse cesarean incisions, women carrying twins, and women with an unknown type of uterine scar are considered appropriate candidates for a TOLAC," said Jeffrey L. Ecker, MD, from Massachusetts General Hospital in Boston and immediate past vice chair of the Committee on Practice Bulletins-Obstetrics who co-wrote the document with William A. Grobman, MD, from Northwestern University in Chicago.
VBAC Counseling on Benefits and Risks
"In making plans for delivery, physicians and patients should consider a woman's chance of a successful VBAC as well as the risk of complications from a trial of labor, all viewed in the context of her future reproductive plans," said Dr. Ecker. Approximately 60-80% of appropriate candidates who attempt VBAC will be successful. A VBAC avoids major abdominal surgery, lowers a woman's risk of hemorrhage and infection, and shortens postpartum recovery. It may also help women avoid the possible future risks of having multiple cesareans such as hysterectomy, bowel and bladder injury, transfusion, infection, and abnormal placenta conditions (placenta previa and placenta accreta).

Uterine Rupture
The risk of uterine rupture during a TOLAC is low—between 0.5% and 0.9%—but if it occurs, it is an emergency situation. A uterine rupture can cause serious injury to a mother and her baby. The College maintains that a TOLAC is most safely undertaken where staff can immediately provide an emergency cesarean, but recognizes that such resources may not be universally available.
"Given the onerous medical liability climate for ob-gyns, interpretation of The College's earlier guidelines led many hospitals to refuse allowing VBACs altogether," said Dr. Waldman. "Our primary goal is to promote the safest environment for labor and delivery, not to restrict women's access to VBAC."
Women and their physicians may still make a plan for a TOLAC in situations where there may not be "immediately available" staff to handle emergencies, but it requires a thorough discussion of the local health care system, the available resources, and the potential for incremental risk. "It is absolutely critical that a woman and her physician discuss VBAC early in the prenatal care period so that logistical plans can be made well in advance," said Dr. Grobman. And those hospitals that lack "immediately available" staff should develop a clear process for gathering them quickly and all hospitals should have a plan in place for managing emergency uterine ruptures, however rarely they may occur, Dr. Grobman added.
The College says that restrictive VBAC policies should not be used to force women to undergo a repeat cesarean delivery against their will if, for example, a woman in labor presents for care and declines a repeat cesarean delivery at a center that does not support TOLAC. On the other hand, if, during prenatal care, a physician is uncomfortable with a patient's desire to undergo VBAC, it is appropriate to refer her to another physician or center.
Practice Bulletin #115, "Vaginal Birth after Previous Cesarean Delivery," is published in the August 2010 issue of Obstetrics & Gynecology.

[mrsjenrn]

This article compares uterine rupture risks. In VBAC patients, it is 0.07%. In women with no previous uterine surgeries, it is about 0.012%.


Uterine Rupture in Pregnancy


Author

Gerard G Nahum, MD, FACOG, FACS Vice President of Global Clinical Development, Women's Healthcare and Primary Care, Bayer HealthCare Pharmaceuticals

Gerard G Nahum, MD, FACOG, FACS is a member of the following medical societies: American Association of Gynecologic Laparoscopists, American College of Obstetricians and Gynecologists, American College of Surgeons, American Society for Reproductive Medicine, and Association of Professors of Gynecology and Obstetrics

Disclosure: Algorithmic Bioscience Inc. Ownership interest Board membership; Biomedical Decision Support Inc. Ownership interest Board membership; Bayer HealthCare Pharmaceuticals Salary Management position
Overview


Uterine rupture in pregnancy is a rare and often catastrophic complication with a high incidence of fetal and maternal morbidity. Numerous factors are known to increase the risk of uterine rupture, but even in high-risk subgroups, the overall incidence of uterine rupture is low. From 1976-2012, 25 peer-reviewed publications described the incidence of uterine rupture, and these reported 2,084 cases among 2,951,297 pregnant women, yielding an overall uterine rupture rate of 1 in 1,146 pregnancies (0.07%).

The initial signs and symptoms of uterine rupture are typically nonspecific, which makes the diagnosis difficult and sometimes delays definitive therapy. From the time of diagnosis to delivery, generally only 10-37 minutes are available before clinically significant fetal morbidity becomes inevitable. Fetal morbidity occurs as a result of catastrophic hemorrhage, fetal anoxia, or both.

The premonitory signs and symptoms of uterine rupture are inconsistent, and the short time for instituting definitive therapeutic action makes uterine rupture in pregnancy a much feared event for medical practitioners.

Definition

Uterine rupture during pregnancy is a rare event and frequently results in life-threatening maternal and fetal compromise. It can either occur in women with (1) a native, unscarred uterus or (2) a uterus with a surgical scar from previous surgery.

Uterine rupture occurs when a full-thickness disruption of the uterine wall that also involves the overlying visceral peritoneum (uterine serosa) is present. By definition, it is associated with the following:
•
Clinically significant uterine bleeding

•
Fetal distress

•
Protrusion or expulsion of the fetus and/or placenta into the abdominal cavity

•
Need for prompt cesarean delivery

•
Uterine repair or hysterectomy


In contrast to frank uterine rupture, uterine scar dehiscence involves the disruption and separation of a preexisting uterine scar. Uterine scar dehiscence is a more common event than uterine rupture and seldom results in major maternal or fetal complications.

Importantly, when the defect in the uterine wall is limited to a scar dehiscence, it does not disrupt the overlying visceral peritoneum and it does not result in clinically significant bleeding from the edges of the pre-existing uterine scar. In addition, in cases of uterine dehiscence (as opposed to uterine rupture), the fetus, placenta, and umbilical cord remain contained within the uterine cavity. If cesarean delivery is needed, it is for other obstetrical indications and not for fetal distress attributable to the uterine disruption.

Although a uterine scar is a well-known risk factor for uterine rupture (most of which arise from prior cesarean delivery), the majority of events involving the disruption of uterine scars result in uterine scar dehiscence rather than uterine rupture. These two entities must be clearly distinguished, as the options for clinical management and the resulting clinical outcomes differ significantly.

Sources of information and study selection

The peer-reviewed literature was searched using the PubMed, Medline, and Cochrane databases for all relevant articles published in the English language. The search terms were uterine rupture, pregnancy and prior cesarean section, vaginal birth after cesarean, VBAC, trial of labor (TOL), trial of labor after cesarean (TOLAC), uterine scar dehiscence, and pregnancy and myomectomy. Standard reference tracing was also used.

Articles published from 1976 through May, 2012 that described the incidence of uterine rupture and that included sufficient information regarding the authors' definitions of uterine rupture and of uterine scar dehiscence were incorporated for review. All studies were observational or reviews. A total of 133 published articles were included for data extraction and analysis.

Incidence and risk factors

Meta-analysis of pooled data from 25 studies in the peer-reviewed medical literature published from 1976-2012 indicated an overall incidence of pregnancy-related uterine rupture of 1 per 1,416 pregnancies (0.07%). When the studies were limited to a subset of 8 that provided data about the spontaneous rupture of unscarred uteri in developed countries, the rate was 1 per 8,434 pregnancies (0.012%).

Congenital uterine anomalies, multiparity, previous uterine myomectomy, the number and type of previous cesarean deliveries, fetal macrosomia, labor induction, uterine instrumentation, and uterine trauma all increase the risk of uterine rupture, whereas previous successful vaginal delivery and a prolonged interpregnancy interval after a previous cesarean delivery may confer relative protection. In contrast to the availability of models to predict the success of a vaginal delivery after a TOLAC, accurate models to predict the person-specific risk of uterine rupture in individual cases are not available.

The major patient characteristics for determining the risk of uterine rupture are noted below.

Uterine status is either native (unscarred) or scarred. Scarred status may include previous cesarean delivery, including the following:
•
Single low transverse (further subcategorized by 1-layer or 2-layer hysterectomy closure)

•
Single low vertical

•
Classic vertical

•
Multiple previous cesarean deliveries


Scarred status may also include previous myomectomy (transabdominal or laparoscopic).

Uterine configuration may be normal or may involve a congenital uterine anomaly.

Pregnancy considerations include the following:
•
Grand multiparity

•
Maternal age

•
Placentation (accreta, percreta, increta, previa, abruption)

•
Cornual (or angular) pregnancy

•
Uterine overdistension (multiple gestation, polyhydramnios)

•
Dystocia (fetal macrosomia, contracted pelvis)

•
Gestation longer than 40 weeks

•
Trophoblastic invasion of the myometrium (hydatidiform mole, choriocarcinoma)


Previous pregnancy and delivery history may include the following:
•
Previous successful vaginal delivery

•
No previous vaginal delivery

•
Interdelivery interval


Labor status is determined as follows:
•
Not in labor

•
Spontaneous labor

•
Induced labor - with oxytocin, with prostaglandins

•
Augmentation of labor with oxytocin

•
Duration of labor

•
Obstructed labor


Obstetric management considerations include the following:
•
Instrumentation (forceps use)

•
Intrauterine manipulation (external cephalic version, internal podalic version, breech extraction, shoulder dystocia, manual extraction of placenta)

•
Fundal pressure


Uterine trauma includes the following:
•
Direct uterine trauma (eg, motor vehicle accident, fall)

•
Violence (eg, gunshot wound, blunt blow to abdomen)

Rupture of the Unscarred Uterus


The normal, unscarred uterus is least susceptible to rupture. Grand multiparity, neglected labor, malpresentation, breech extraction, and uterine instrumentation are all predisposing factors for uterine rupture. A 10-year Irish study by Gardeil et al showed that the overall rate of unscarred uterine rupture during pregnancy was 1 per 30,764 deliveries (0.0033%). No cases of uterine rupture occurred among 21,998 primigravidas, and only 2 (0.0051%) occurred among 39,529 multigravidas with no uterine scar.[1]

A meta-analysis of 8 large, modern (1975-2009) studies from industrialized countries revealed 174 uterine ruptures among 1,467,534 deliveries. This finding suggests that the modern rate of unscarred uterine rupture during pregnancy is 0.012% (1 in 8,434). This rate of spontaneous uterine rupture has not changed appreciably over the last 50 years, and most of these events occur at term and during labor. An 8-fold increased incidence of uterine rupture of 0.11% (1 in 920) has been noted in developing countries, with this increased incidence of uterine rupture having been attributed to a higher-than-average incidence of neglected and obstructed labor due to inadequate access to medical care.

When the risk of uterine rupture for women with different types of risk factors is assessed, these baseline rates of pregnancy-related uterine rupture in women with native, unscarred uteri, specifically, the rates of 0.012% (1 in 8,434) for women living in industrialized countries and 0.11% (1 in 920) for women living in developing countries, represent observational benchmarks that should be referenced for all comparisons.

Effect of maternal parity

Many authors have considered multiparity a risk factor for uterine rupture. Golan et al noted that, in 19 of 61 cases (31%), uterine rupture occurred in women with a parity of more than 5.[2] Schrinsky and Benson found that 7 of 22 women (32%) who had unscarred uterine rupture had a parity of greater than 4.[3] In a study by Mokgokong and Marivate, the mean parity for women who had pregnancy-related uterine rupture was 4.[4] Despite the apparent increase in the risk of uterine rupture associated with high parity, Gardeil et al found only 2 women with uterine rupture among 39,529 multigravidas who had no previous uterine scar (0.005%).[1]

Rupture of the unscarred uterus before labor versus during labor

Schrinsky and Benson reported 22 cases of uterine rupture in gravidas with unscarred uteri. Nineteen occurred during labor (86%), and 3 occurred before labor (14%). This percentage was markedly different from that of gravidas with a previous uterine scar, for whom the timing of uterine rupture between labor and the antepartum period was nearly evenly distributed.[3]

Oxytocin augmentation and induction of labor in the unscarred uterus

The use of oxytocin for labor augmentation versus labor induction is often quite different. The two patient populations widely vary in their key attributes, as well as in the oxytocin doses that are typically given, which systematically varies between the two groups. Despite this, many investigations concerning the use of oxytocin and the risk of uterine rupture have failed to make this distinction.

In 1976, Mokgokong and Marivate reported 260 uterine ruptures among 182,807 deliveries that involved unscarred uteri, and 32 of the 260 (12%) were associated with oxytocin use.[4] Rahman et al similarly found that oxytocin was administered in 9 of 65 cases (14%) that involved unscarred uterine rupture.[5] Golan et al noted that, among 126,713 deliveries, oxytocin was used in 26 of 61 cases (43%) that involved unscarred uterine rupture.[2] However, Plauche et al attributed only 1 of 23 unscarred uterine ruptures (4%) to the use of oxytocin.[6]

Based on this type of limited information, the increased risk of uterine rupture attributable to the use of oxytocin in gravidas with unscarred uteri is uncertain. However, women who have had a cesarean delivery appear to have an increased risk of uterine rupture associated with the use of oxytocin, both when it is used for labor augmentation and labor induction (see Table 1).

Congenital uterine anomalies

In a review article, Nahum reported that congenital uterine anomalies affect approximately 1 in 200 women.[7] In such cases, the walls of the abnormal uteri tend to become abnormally thin as pregnancies advance, and the thickness can be inconsistent over different aspects of the myometrium (uterine musculature).[8, 9, 10, 11]

Ravasia et al reported an 8% incidence of uterine rupture (2 of 25) in women with congenitally malformed uteri compared with 0.61% (11 of 1,788) in those with normal uteri (P =.013) who were attempting VBAC.[12] Both cases of uterine rupture in the women with uterine anomalies involved labor induction with prostaglandin E2.

In contrast, a study of 165 patients with Müllerian duct anomalies who underwent spontaneous labor after 1 prior cesarean delivery reported no cases of uterine rupture.[13] Of note, in this study 36% (60 of 165) had only a minor uterine anomaly (arcuate or septate uterus), and 64% (105 of 165) had a major uterine anomaly (unicornuate, didelphys, or bicornuate uterus). Moreover, only 6% (10 of 165) of patients with Müllerian duct anomalies underwent induction of labor.

For pregnancies that implant in a rudimentary horn of a uterus, a particularly high risk of uterine rupture is associated with the induction of labor (≤ 81%; 387 of 475 cases).[14] Importantly, 80% of ruptures involving these types of rudimentary horn pregnancies occurred before the third trimester, with 67% occurring during the second trimester.

The decision for induction of labor in women with a congenitally anomalous uterus, especially in cases of a previous cesarean delivery, must be carefully considered, given the higher incidence of uterine rupture reported in this patient population. Although the uterine rupture rate for unscarred anomalous uteri during pregnancy is increased relative to that for normal uteri, the precise increase in risk associated with the different types of uterine malformations remains uncertain.

[mrsjenrn]

Same Article, continued. VBAC specifics!

Rupture of the Scarred Uterus Due to Previous Cesarean Delivery


The effect of previous cesarean delivery on the risk of uterine rupture has been studied extensively. In a meta-analysis, Mozurkewich and Hutton used pooled data from 11 studies and showed that the uterine rupture rate for women undergoing a TOLAC was 0.39% compared with 0.16% for patients undergoing elective repeat cesarean delivery (odds ratio [OR], 2.10; 95% CI, 1.45-3.05). After restricting the meta-analysis to 5 prospective cohort trials, similar results were found (OR, 2.06; 95% CI, 1.40-3.04).[26]

Hibbard et al examined the risk of uterine rupture in 1,324 women who underwent a TOLAC. They reported a significant difference in the risk of uterine rupture between women who achieved successful vaginal birth compared with women in whom attempted vaginal delivery failed (0.22% vs 1.9%; OR, 8.9; 95% CI, 1.9-42).[27] The effect of previous cesarean delivery on the rate of subsequent pregnancy-related uterine rupture can be further examined according to additional subcategories, which are summarized in Table 1.

Relevant to this issue of vaginal birth after cesarean section (VBAC) is that the overall rate in the United States increased from 3.4% in 1980 to a peak of 28% in 1996. Commensurate with this 8-fold increase in the VBAC rate, reports of maternal and perinatal morbidity also increased, in particular with reference to uterine rupture. By 2007, the VBAC rate in the United States had fallen nationally to 8.5%. Not surprisingly, the cesarean delivery rate also reached an all-time high of 32% in 2007. In its most recent guidelines pertaining to VBAC in August 2010, the American Congress of Obstetricians and Gynecologists (ACOG) adopted the recommendation not to restrict women's access to VBAC.[28] This occurred after the National Institutes of Health (NIH) Consensus Development Conference Panel reviewed the totality of the evidence concerning maternal and neonatal outcomes relating to VBAC in March 2010.[29]

Previous classic cesarean delivery

Classic cesarean delivery via vertical midline uterine incision is infrequently performed in the modern era and currently account for 0.5% of all births in the United States.[30] In a meta-analysis, Rosen et al reported an 11.5% absolute risk of uterine rupture (3 of 26 cases) in women with classic vertical cesarean scars who underwent an unplanned TOLAC.[31] For women who underwent repeat cesarean section, Chauhan et al reported that the uterine rupture rate for 157 women with prior classical uterine cesarean scars was 0.64% (95% CI, 0.1-3.5%). All patients in that study underwent repeat cesarean delivery, but a high rate of preterm labor resulted in 49% of the patients being in labor at the time of their cesarean delivery.[30]

Landon et al reported a 1.9% absolute uterine rupture rate (2 of 105 cases) in women with a previous classic, inverted T, or J incision who either presented in advanced labor or refused repeat cesarean delivery.[32] These rates of frank uterine rupture in women with classic cesarean deliveries are in contrast to the higher rates of 4-9% that the American College of Obstetricians and Gynecologists (ACOG) had historically reported for women with these types of uterine scars. However, Chauhan et al observed a 9% rate of asymptomatic uterine scar dehiscence (95% CI, 5-15%).[30] This result suggests that disruptions of uterine scars might have been misclassified as true ruptures instead of dehiscences in previous studies; this error may explain the bulk of the discrepancy.

Previous low vertical cesarean delivery

A meta-analysis of pooled data from 5 studies demonstrated a 1.1% absolute risk (12 of 1,112 cases) of symptomatic uterine rupture in women undergoing a TOLAC with a low vertical cesarean scar.[33, 34, 35, 36, 32] Compared to women with low transverse cesarean scars, these data suggest no significantly increased risk of uterine rupture or adverse maternal and perinatal outcomes.

Interpretation of these studies is hampered by inconsistencies in how high the lower uterine segment could be cut before it was considered a classic incision. Even when the lower uterine segment is already well developed as a result of active labor, a low vertical incision of adequate length is often impossible to permit fetal delivery. Naef et al arbitrarily defined a 2-cm extension into the upper segment as a classic extension. For 322 pregnancies that occurred after a low vertical cesarean delivery, the overall rate of uterine rupture was 0.62%. This rate could be further divided as 1.15% for 174 women who underwent a TOLAC compared with no ruptures among 148 women who underwent elective repeat cesarean delivery.[33]

Unknown uterine scar

In many instances, the type of incision used for a prior cesarean delivery cannot be confirmed due to unavailability of the operative report. Under these circumstances, the assessment of uterine rupture risk may sometimes be guided by the obstetric history to infer the most probable type of uterine scar. For example, a patient with a history of a preterm cesarean delivery at 28 weeks’ gestation has a much higher likelihood of having had a vertical uterine incision than a patient who underwent a cesarean section for an indication of arrest of fetal descent at term.

It has been argued that because most cesarean deliveries in the United States are accomplished via low-transverse uterine incisions, the risk of uterine rupture for patients with an unknown scar is similar to that for women who have previously undergone a low-transverse hysterotomy. This logic depends on the high ratio of low-transverse to vertical incisions performed for cesarean section, but it ignores the varying probability with which different types of uterine incisions are made under different obstetrical circumstances, as well as differences that occur due to varying medical resources and the prevailing local practitioner practices in countries other than the United States (eg, practices that occur in other countries, such as Mexico or Brazil). Nevertheless, the vast majority of cesarean deliveries performed in the United States are accomplished via low-transverse uterine incisions.

In a small case-control study of 70 patients by Leung et al, no association was found between an unknown uterine scar and the risk of uterine rupture; however, given the rarity of uterine rupture (see Table 1), this study was vastly underpowered to detect such a difference.[37] Two additional, but similarly underpowered, case series have also reported comparable rates of uterine rupture and VBAC success in women with unknown uterine cesarean delivery scars versus those with documented previous low-transverse hysterotomies.[38, 39] The Maternal-Fetal Medicine Units (MFMU) Network cesarean delivery registry reports a 0.5% risk (15 of 3,206) of uterine rupture for patients who underwent a TOLAC with an unknown uterine scar.[32]

For cases in which there are 1 or 2 unknown prior uterine incisions, there is a single small, randomized, controlled trial by Grubb et al that compared labor augmentation with oxytocin (n=95) with no intervention (n=93) in women with prior cesarean deliveries involving either 1 or 2 unknown uterine incisions. Four uterine dehiscences and 1 uterine rupture occurred, all in the group that underwent labor augmentation. In the 1 case of uterine rupture, the unknown uterine scar was in a patient with 2 prior cesarean deliveries, one of which involved a vertical incision. Had the uterine scar status for this patient been known in advance, it would have represented a contraindication to TOLAC.[40]

Previous low transverse cesarean delivery

The risk of uterine rupture after a low transverse cesarean delivery varies depending on whether patients undergo a TOLAC or an elective repeat cesarean delivery and on whether labor is induced or spontaneous, as well as other factors. The vast majority of cesarean deliveries in the United States are of the low transverse type. For women who have had 1 previous cesarean delivery, examining the various risk factors for uterine rupture is instructive. These absolute risks for uterine rupture are discussed below, as well as in Table 1.

Previous cesarean delivery without a subsequent trial of labor

In a study of 20,095 women by Lydon-Rochelle et al, the spontaneous uterine rupture rate among 6,980 women with a single cesarean delivery scar who underwent scheduled repeat cesarean delivery without a TOL was 0.16%.[41] This finding indicates that uteri with cesarean scars have an intrinsic propensity for rupture that exceeds that of the unscarred organ during pregnancy, which is 0.012% (OR increase of approximately 12-fold). Therefore, all other uterine rupture rates in women with a previous cesarean delivery should be referenced to this expected baseline rate.

Previous cesarean delivery with subsequent spontaneous labor

A study by Lydon-Rochelle et al showed that the uterine rupture rate among 10,789 women with a single previous cesarean delivery who labored spontaneously during a subsequent singleton pregnancy was 0.52%.[41] This rate of uterine rupture implies an increased relative risk (RR) of 3.3 (95% CI, 1.8-6.0) for women who labor spontaneously compared with women who undergo elective repeat cesarean delivery.

In a study by Ravasia et al of 1,544 patients with a previous cesarean delivery who later labored spontaneously, the uterine rupture rate was 0.45%.[42] Zelop et al found that, among 2,214 women with 1 previous cesarean delivery who labored spontaneously, the uterine rupture rate was 0.72%.[43] The authors of this article performed a meta-analysis of 29,263 pregnancies from 9 studies from 1987-2004 and showed that the overall risk of uterine rupture was 0.44% for women who labor spontaneously after a previous cesarean delivery.

Previous cesarean delivery with subsequent augmentation of labor

Despite the clinical heterogeneity and different VBAC success rates for women undergoing spontaneous labor rather than either labor augmentation or induction, very few studies have stratified their data by labor augmentation versus labor induction and the data that do exist are conflicting. There is wide variance in the frequency of clinical use of oxytocin as well as in the dose and dosing schedules of oxytocin that are used. As a result, there is a paucity of specific evidence-based clinical guidelines for the use of oxytocin in VBAC trials.

In a study by Blanchette et al, the rate of uterine rupture for 288 women who underwent oxytocin augmentation of labor after a previous cesarean delivery was 1.4%, compared with 0.34% for 292 women who underwent a trial of spontaneous labor. This finding suggests a 4-fold increased risk of uterine rupture in women who undergo labor augmentation with oxytocin compared with spontaneous labor after a previous cesarean delivery.

In the MFMU Network study, the rate of uterine rupture with oxytocin augmentation was 0.9% (52 of 6,009 cases) versus 0.4% (24 of 6,685 cases) without oxytocin use. In contrast, a meta-analysis of studies published prior to 1989 found that the use of oxytocin was unassociated with uterine rupture.[29]

Zelop et al also found that labor augmentation with oxytocin did not significantly increase the risk for uterine rupture.[42] Pooled data in Table 1 show a trend towards an increased rate of uterine rupture, albeit small, with oxytocin use. However, the conclusions to be drawn from this are both limited and suspect because, in general, no proper adjustment has been made for the potential (and very likely) confounding-by-indication that occurs in the observational studies that attempt to compare the rate of uterine rupture for women receiving treatment with oxytocin versus those who do not (eg, proper propensity score matching has not been performed).

In this regard, assessment of the safety of oxytocin use in VBAC trials must consider both the dosage and the time of exposure. These issues were addressed by Cahill et al in a nested case-control study of 804 patients within a multicenter, retrospective cohort of 25,005 patients with at least 1 prior cesarean delivery who underwent a TOLAC. At an intravenous oxytocin dosage range of 6-20 mU/min, a more than 3-fold increased risk of uterine rupture was associated with oxytocin use (HR [hazard ratio], 3.34, 95% CI 1.01-10.98). At dosage range of more than 20 mU/min, a nearly 4-fold increased risk of uterine rupture (HR, 3.92; 95% CI, 1.06-14.52) was noted. The attributable risk of uterine rupture associated with oxytocin use was 2.9% and 3.6% for the maximum oxytocin dose ranges of more than 20 mU/min and more than 30 mU/min, respectively.

The authors did not find a significant risk association between time (in terms of both duration of oxytocin exposure and duration of labor) and uterine rupture risk.They suggest an upper limit of 20 mU/min of oxytocin for use in VBAC trials and a judicious approach to the use and monitoring of oxytocin for both labor augmentation and induction.

The benefit of intrauterine pressure catheter (IUPC) monitoring of uterine contractions in VBAC trials is unclear, with only a single small case series failing to detect differences in fetal or maternal morbidity/mortality associated with uterine rupture when an IUPC was used instead of external tocodynamometry. Nevertheless, many institutions have found the IUPC useful in allowing careful titration of oxytocin dosing, especially when maternal habitus poses a limit to the accurate external monitoring of uterine contractions in women undergoing a TOLAC.

Previous cesarean delivery with subsequent induction of labor

Emerging data indicate that induction of labor after a prior cesarean delivery appears to be associated with an increased risk of uterine rupture.

Zelop et al found that the rate of uterine rupture in 560 women who underwent labor induction after a single previous cesarean delivery was 2.3% compared with 0.72% for 2,214 women who had labored spontaneously (P =.001).[43]

In a study by Ravasia et al of 575 patients who underwent labor induction, the uterine rupture rate was 1.4% compared with 0.45% for women who labored spontaneously (P =.004).[42]

Blanchette et al found that the uterine rupture rate after previous cesarean delivery when labor was induced was 4% compared with 0.34% for women who labored spontaneously.[44] This last finding suggests a 12-fold increased risk of uterine rupture for women who undergo labor induction after previous cesarean delivery.

Data on mechanical methods of labor induction for cervical ripening are limited but reassuring. In a small case series, Bujold et al found no statistically significant difference among the uterine rupture rates of 1.1% for spontaneous labor, 1.2% for induction by amniotomy with or without oxytocin, and 1.6% for induction by transcervical Foley catheter (P =0.81).[45]

Conversely, Hoffman et al reported a 3.67-fold increased risk of uterine rupture (95% CI, 1.46-9.23) with Foley catheter use for preinduction cervical ripening. Importantly, however, many of these patients received concomitant oxytocin together with application of the transcervical Foley catheter.[46]

Of particular note is that a recent randomized controlled trial by Pettker et al found that the addition of oxytocin to the use of a transcervical Foley catheter for labor induction does not shorten the time to delivery and has no effect on either the likelihood of delivery within 24 hours or the vaginal delivery rate.[47] In light of these findings, induction of labor with a transcervical Foley catheter alone may be a reasonable option for women undergoing a TOLAC with an unfavorable cervix.

Use of prostaglandins for cervical ripening and induction of labor after previous cesarean delivery

Current ACOG guidelines discourage the use of prostaglandins to induce labor in most women with a previous cesarean delivery. This recommendation is based on considerable evidence for an increased risk of uterine rupture associated with prostaglandins. Lydon-Rochelle et al reported a 15.6-fold increased risk for uterine rupture (95% CI, 8.1-30) when prostaglandins were used in gravidas who underwent a TOLAC. In 366 women with scars from a previous cesarean delivery who underwent labor induction with prostaglandins, the uterine rupture rate was 2.45% compared with 0.77% without prostaglandin use.[41]

Taylor et al identified 3 uterine ruptures among 58 patients with 1 previous cesarean delivery who received prostaglandin E2 (PGE2) alone for labor induction. The uterine rupture rate was 5.2% (3 of 58) compared with 1.1% (8 of 732) among patients not treated with prostaglandin.[48] Ravasia et al found that 3 ruptures occurred among 172 patients who underwent labor induction with PGE2 alone (1.7%), which was significantly higher than 0.45% (7 of 1,544) women who labored spontaneously.[42]

In contrast, Flamm et al found a uterine rupture rate of 1.3% (6 of 453) in patients with a previous cesarean delivery who were treated with PGE2 in combination with oxytocin. This result was not significantly different from the rate of 0.7% (33 of 4,569) in women who were not treated with PGE2.[49] In a small study, Delaney and Young also did not find a significant difference in uterine rupture rates between patients with scars from a previous cesarean delivery who underwent labor induction with PGE2 and patients with previous cesarean scars who labored spontaneously (1.1 vs 0.3%; P =.15).[50]

Landon et al reported no uterine ruptures among 227 patients who underwent induction with prostaglandins alone. Although the study was underpowered to detect small differences, the particular type of prostaglandin administered did not appear to significantly affect the uterine rupture rate (52 patients received misoprostol; 111, dinoprostone; 60, PGE2 gel; and 4, combined prostaglandins).[32]

Previous cesarean delivery with previous successful vaginal delivery

Several studies have shown a protective association of previous vaginal birth on uterine rupture risk in subsequent attempts at vaginal birth after previous cesarean delivery. Zelop et al compared 1,021 women who underwent a TOL after a single previous cesarean delivery with 1 previous vaginal delivery with 2,762 women who underwent a TOL with no previous vaginal delivery. The uterine rupture rate was 0.2% versus 1.1% (P =.01).[51]

Among women with a single uterine scar, those with at least 1 previous vaginal delivery had one fifth the risk for uterine rupture compared with women without a previous vaginal delivery (OR, 0.2; 95% CI, 0.04-0.8). Caughey et al found that women with a previous vaginal delivery were about one fourth as likely as patients without a previous vaginal delivery to have a uterine rupture (OR, 0.26; 95% CI, 0.08-0.88).[52] In a study of 205 patients who underwent a TOL after 1 previous cesarean delivery, Kayani and Alfirevic noted that all 4 of their cases of uterine ruptures occurred in women with no previous vaginal delivery.[53]

A study of 11,778 women by members of the Maternal-Fetal Medicine Units (MFMU) Network found that in women with no prior vaginal delivery who underwent a TOLAC, there was an increased risk of uterine rupture with induction versus spontaneous labor (1.5% vs 0.8%, P =0.02). In contrast, no statistically significant difference was shown for women with a prior vaginal delivery who underwent spontaneous TOLAC compared with labor induction (0.6% vs 0.4%, P =0.42).[54]

Previous cesarean delivery with subsequent successful VBACs

Multiple studies suggest a protective advantage with regard to the uterine rupture rate if a woman has had a prior successful VBAC attempt. Multiple potential explanations exist, but the 2 most obvious are that a successful prior VBAC attempt assures that (1) the maternal pelvis is tested and that the bony pelvis is adequate to permit passage of the fetus and (2) the integrity of the uterine scar has been tested previously under the stress/strain conditions during labor and delivery that were adequate to result in vaginal delivery without prior uterine rupture.

Mercer et al found that the rate of uterine rupture decreased after the first successful VBAC, but that there was no additional protective effect demonstrated thereafter: the uterine rupture rate was 0.87% with no prior VBACs, 0.45% for those with one successful prior VBAC, and 0.43% for those with 2 or more successful prior VBACs (P =.01).[55] Pooled data from 5 studies indicate an increased uterine rupture rate of 1.4% (1 per 73) in failed VBAC attempts that required a repeat cesarean section in labor.[32, 44, 56, 57, 58]

Interdelivery interval

In a case-control study by Esposito et al, an interpregnancy interval between cesarean delivery and a subsequent pregnancy of < 6 months was nearly 4 times as common among patients who had uterine rupture than in control subjects (17.4 vs 4.7%; OR, 3.92; 95% CI, 1.09-14.3). Among 23 patients who had uterine rupture after a previous cesarean delivery, the mean interpregnancy interval was 20.4 ± 15.4 months compared with 36.5 ± 30.4 months for control patients (P =.01).[59] Stamilio et al recently confirmed a similar uterine rupture rate of 2.7% in women with an interdelivery interval of < 6 months compared with 0.9% for those having interdelivery intervals of ≥6 months (adjusted OR 2.66, 95% CI, 1.21-5.82).[60]

Shipp et al similarly found that the risk of symptomatic uterine rupture was increased 3-fold in women with interdelivery intervals of< 18 months when they underwent a TOLAC after 1 previous cesarean delivery (OR, 3.0; 95% CI, 1.2-7.2).[61] The authors controlled for maternal age, public assistance, length of labor, gestational age of ³41 weeks, and induction of augmentation of labor with oxytocin.

In additional support of this observation, a Canadian study by Bujold et al reported on 1,527 women who underwent a TOL after a single previous low-transverse cesarean delivery, finding that 2.8% of patients who had an interdelivery interval of ≤24 months had a uterine rupture compared with 0.9% for those with an interdelivery interval of >24 months (P < .01).[62] After adjusting for confounding variables, the odds ratio for a uterine rupture during a subsequent TOLAC was 2.65 for women who had an interdelivery interval of ≤24 months compared with women who had a longer interdelivery interval (95% CI, 1.08-5.46).

In a follow-up study, the same authors examined the risk of uterine rupture between 18-24 months. After adjustment for confounding factors, they found that an interdelivery interval shorter than 18 months was associated with a significant increase of uterine rupture (odds ratio [OR], 3; 95% confidence interval [CI], 1.3–7.2), whereas an interdelivery interval of 18-24 months was not (OR, 1.1; 95% CI, 0.4–3.2). In agreement with the findings by Shipp et al, the study by Bujold et al concludes that an interdelivery interval shorter than 18 months but not between 18-24 months should be considered as a risk factor for uterine rupture.[63]

The authors speculated that a prolonged interpregnancy interval may allow time for the previous cesarean delivery scar to reach its maximal tensile strength before the scar undergoes the mechanical stress and strain with a subsequent intrauterine pregnancy. Interestingly, the authors also observed that the combination of a short interdelivery interval of ≤24 months and a single-layer hysterotomy closure was associated with a uterine rupture rate of 5.6%. This is comparable to the rate of uterine rupture for patients undergoing a TOLAC with a previous classic midline cesarean scar.

One-layer versus 2-layer hysterotomy closure

In a Canadian study of 1,980 women who underwent a TOL after a single previous low transverse cesarean delivery, Bujold et al found a 4- to 5-fold increased risk of uterine rupture for women who had a previous single-layer uterine closure compared with those having a two-layer closure. Uterine rupture occurred in 3.1% (15 of 489 cases) of single-layer closure versus 0.5% (8 of 1,491 cases) of two-layer closure (P < .001). Using stepwise multivariate logistic regression, the authors concluded that the OR for uterine rupture in women who had undergone a single previous one-layer cesarean hysterotomy closure was 3.95 (95% CI, 1.35-11.49) compared with those who had a two-layer closure.[64]

The same authors reported a multicenter, case-control study comparing 96 cases of uterine rupture with 288 controls. Prior single-layer closure carried more than twice the risk of uterine rupture compared with two-layer closure. In multivariate analysis, single-layer closure was linked to an increased rate of uterine rupture (odds ratio [OR] 2.69; 95% confidence interval [CI] 1.37–5.28). The authors concluded that single-layer closure should be avoided in women who contemplate future VBAC delivery.[65]

Durnwald and Mercer found that 182 patients with single-layer hysterotomy closure did not have an increased rate of uterine rupture, but the rate of uterine windows at subsequent delivery was increased to 3.5% versus 0.7% for those who had a multi-layer closure (P =.046).[66]

Gyamfi et al reported an 8.6% (3 of 35) rate of uterine rupture in patients with a single-layer closure compared with 1.3% (12 of 913) in those with double-layer closure (P =0.015). Although the single-layer group had a shorter interdelivery interval, the uterine rupture rate remained significantly elevated even when the time interval was controlled for using logistic regression (OR 7.20, 95% CI, 1.81-28.62, P =0.005).[67]

Multiple prior cesarean deliveries

For women with a history of 2 or more cesarean deliveries, 10 studies published from 1993-2010 showed that the risk of uterine rupture in a subsequent pregnancy ranged from 0.9-6.0% (1 per 17-108 pregnancies). This risk is increased 2- to 16-fold compared to women with only a single previous cesarean delivery. In a study of 17,322 women with scars from cesarean delivery, Miller et al found that, when women underwent a TOLAC, uterine rupture was 3 times more common with 2 or more scars (1.7%) than with 1 scar (0.6%) [OR, 3.06; 95% CI, 1.95-4.79; P < .001].[68]

In the largest analysis to date, Macones et al reviewed data from 17 tertiary and community hospitals and found that, in 1,082 women with 2 uterine scars who underwent a TOLAC, the risk of uterine rupture was increased 2-fold compared with women with only 1 uterine scar (absolute rupture risk 1.8% vs 0.9%; adjusted OR, 2.3; 95% CI, 1.37-3.85).[69]

In the only study to control for potential confounding variables, Caughey et al concluded that in women who had 2 previous cesarean deliveries who then attempted vaginal birth, the risk of uterine rupture was almost 5 times the risk of those with only 1 previous cesarean delivery (3.7% vs 0.8%; P =.001). The study controlled for several key covariates, including the use of prostaglandin E2 gel, oxytocin induction, oxytocin augmentation, length of labor, and epidural use. They also found that women with a previous vaginal delivery were about one fourth as likely to have a uterine rupture as women without a previous vaginal delivery (OR, 0.26; 95% CI, 0.08-0.88).[52]

In contrast, Landon et al reported through the MFMU Network that there was no significant difference in the uterine rupture rate for women with multiple prior cesarean deliveries versus 1 prior cesarean delivery (0.9% vs 0.7%; P= 0.37).[70] However, in this study there was a much lower TOLAC rate of 9% for women with multiple prior cesarean deliveries compared with the 27% rate in the report of Macones et al[69] and the 73% rate in Miller’s study[68] . This indicates that there were much more stringent inclusion/exclusion criteria applied by Landon et al, and that this difference may account for the apparent discrepancy in outcomes. Caughey et al did not report the TOLAC rate in their 12-year data analysis.[52]

A recent meta-analysis of 17 studies including 5,666 patients undergoing a TOL after 2 or more cesarean deliveries demonstrated a 1.36% uterine rupture rate.[71] This is similar to the result of our pooled data analysis from 10 studies published from 1993-2010, which shows a 1.81% uterine rupture rate for patients with multiple previous cesarean delivery scars.

A 2004 ACOG guideline suggested that in women with 2 previous cesarean deliveries, only those with a previous vaginal delivery should be considered candidates for a TOLAC.[72] This ACOG recommendation was subsequently revised in an updated 2010 guideline to suggest that women with two previous low transverse cesarean deliveries may be considered candidates for TOLAC regardless of their prior vaginal delivery status.[28]

Maternal age

Shipp et al showed that advancing maternal age is associated with an increased rate of uterine rupture. In a multiple logistic regression analysis designed to control for confounding factors, the overall rate of uterine rupture among 3,015 women with 1 previous cesarean delivery was 1.1%. The rate of uterine rupture in women older than 30 years (1.4%) versus younger women (0.5%) differed significantly (OR, 3.2; 95% CI, 1.2-8.4).[73]

Multiple gestation

Most large series of VBAC with twin gestations report similar rates of uterine rupture for twin and singleton gestations. In an analysis of the largest database of inpatient hospitalizations available in the United States from 1993-2002, Ford et al studied 1,850 women with twin gestations attempting VBAC and found similar uterine rupture rates compared with singleton gestations (0.9% vs 0.8%).[74]

Similarly, Cahill et al compared 535 twin pregnancies with 24,307 singleton pregnancies and reported a comparable uterine rupture rate of 1.1% for twin vs 0.9% for singleton pregnancies (OR, 1.2; 95% CI, 0.3-4.6) in women with at least 1 previous cesarean delivery undergoing TOLAC.[75] Additionally, they found that patients with twins were less likely to attempt a TOLAC (OR, 0.3; 95% CI 0.2-.04), but no more likely to have a VBAC failure (OR, 1.1; 95% CI, 0.8-1.6), or major maternal morbidity (OR, 1.6; 95% CI, 0.7-3.7).

Overall, women with multifetal gestations attempting VBAC did not incur any greater risk of uterine rupture than their singleton controls. In a nested case-control study of the MFMU cesarean registry, Varner et al compared cases of women undergoing TOLAC with one previous cesarean delivery with a multifetal pregnancy versus controls with one previous cesarean delivery with a singleton pregnancy.[76] A similar uterine rupture rate of 0.7% was found in both multifetal (4/556) versus singleton groups (99/13,923) [ORadj 1.19 (0.43-3.30)] . In a smaller study, Aaronson et al reported no cases of uterine rupture among 134 twin pregnancies undergoing a TOLAC with a single prior cesarean section.[77] The ACOG 2010 guidelines for VBAC recommend that women with one previous cesarean delivery with a low transverse incision, who are otherwise appropriate candidates for twin vaginal delivery, may be considered candidates for TOLAC.[28]

Fetal macrosomia

Elkousy et al found that, in 9,960 women who underwent a TOLAC after 1 previous cesarean delivery, the risk of uterine rupture was significantly greater for fetuses that weighed more than 4000 g (2.8%) than in those weighing less than 4000 g (1.2%; RR 2.3, P < .001). For women with 1 previous cesarean delivery and no previous vaginal deliveries, the uterine rupture rate was 3.6% for women with a fetal weight of more than 4000 g compared to women with a fetal weight of < 4000 g (RR 2.3, P < .001).[78] More recently, Jastrow et al showed that birth weight was directly correlated with the rate of uterine rupture, with uterine rupture rates of 0.9%, 1.8%, and 2.6% for birth weights of less than 3500 g, 3500-3999 g, and 4000 g or larger, respectively (P < .05).[79]

Zelop et al reported that the rate of uterine rupture for women delivering neonates weighing >4000 g was 1.6% versus 1% for newborns ≤4000 g, but that the difference was not statistically significant (P =0.24).[80] Flamm et al examined TOLAC risks in a cohort of 301 women and reported no difference between the rates of uterine rupture for women with neonates weighing ≥4000 gm versus < 4000 gm.[81] The ACOG 2010 VBAC guidelines suggest that suspected fetal macrosomia alone should not preclude the possibility of TOLAC.[28]

Gestation beyond 40 weeks

The effect of advancing gestational age on the safety and success of TOLAC is of great clinical significance in the counseling of postterm VBAC candidates. In a Canadian study that evaluated 329 patients with advanced gestational age of ≥41 weeks, Hammoud et al reported a significantly increased rate of uterine rupture of 2.7% compared to 1.0% among 1,911 patients with gestational ages between 37-40 6/7 weeks (p=0.006).[82] After adjusting for confounding variables, advanced gestational age was associated with a lower rate of successful vaginal delivery (OR 0.68, 95% CI 0.51–0.89) and a higher rate of uterine rupture (OR 2.85, 95% CI 1.27–6.42) when compared to those pregnancies of gestational age between 37–40 6/7 weeks. Similarly, a British study by Kiran et al found a significantly increased rate of uterine rupture of 2.1% (10 of 466) in women undergoing TOLAC beyond 40 weeks of gestation compared to 0.3% (4 of 1,154) for those with gestational ages of ≤40 weeks(OR6.3,CI1.9-20.2).[83]

The largest study to evaluate the effect of delivery beyond 40 weeks of gestation has not found this association, however. Among 4,680 women undergoing a TOLAC at a gestational age of 40 weeks or longer, Coassolo et al reported a uterine rupture rate of 1.1% (52 of 4,680), which was not statistically different from the uterine rupture rate of 1.0% (68 of 6,907) found in women with a gestational age of less than 40 weeks.[84] When the investigational cohort was defined as those pregnancies of 41 weeks' gestation or longer, the risk of uterine rupture and overall morbidity was also not increased.

The difference in these results may arise from the small sample sizes of the Canadian and British studies and/or the accuracy of gestational age estimates by last menstrual period dating with early ultrasound confirmation, which was not clearly defined in the study of Coassalo et al. Zelop et al reported similar findings of no significant difference in uterine rupture rate of 1.3% (17 of 1,271) in women undergoing TOLAC at more than 40 weeks of gestation versus 0.8% (12 of 1,504) in women at 37-40 weeks of gestation (P = 0.2).[85]

Moreover, the latter authors reported that the risk of uterine rupture does not increase substantially after 40 weeks of gestation, but is increased with induction of labor regardless of gestational age. For spontaneous labor, uterine ruptures occurred in 0.5% of gravidas delivering at or before 40 weeks compared with 1.0% for those delivering after 40 weeks (P = 0.2). For induced labor, the rates of uterine rupture were 2.1% for gravidas at or before 40 weeks and 2.6% for those after 40 weeks (P = 0.7)

The ACOG 2010 VBAC guidelines suggest that although the chance of success may be lower for a vaginal delivery in more advanced gestations, gestational age beyond 40 weeks alone should not preclude a TOLAC.[28] [#Table1]

Table 1. Absolute Rates of Uterine Rupture for Different Patient Subgroups (Open Table in a new window)


General Category Subcategory Uterine Rupture Years



of Data Collection



No.



of Studies



References
Major Minor Total Deliveries Rate Total No.



in Sub-category




All NA NA 2,951,297 1 per 1,426 (0.07%) 2,084 1973-2010 25 Gardeil 1994, Golan 1980, Schrinsky 1978, Mokgokong 1976, Rahman 1985, Plauche 1984, Landon 2004, Gregory 1999, McMahon 1996, Rageth 1999, Elkousy 2003, Yap 2001, Leung 1993, Miller 1997, Kieser 2002, Bujold 2002, Ofir 2004, Flamm 1994, Menihan 1998, Zwart 2009
Unscarred uterus In industrialized countries NA 1,467,534 1 per 8,434 (0.013%) 174 1975-2006 8 Gardeil 1994, Plauche 1984, Gregory 1999, Rageth 1999, Yap 2001, Miller 1997, Kieser 2002, Zwart, 2009
In developing countries NA 399,314 1 per 920 (0.11%) 434 1966-2006 4 Golan, 1980, Mokgokong 1976, Rahman 1985, Gupta 2010
Elective primary cesarean delivery NA 17,209 1 per 1,324 (0.08%) 13 1995 1 Gregory 1999
TOLAC NA 452,720 1 per 4,975 (0.02%) 91 1995 1 Gregory 1999
Labor with vaginal delivery NA 401,387 1 per 14,866 (0.01%) 27 1995 1 Gregory 1999
Failed labor with primary cesarean delivery NA 51,333 1 per 802 (0.12%) 64 1995 1 Gregory 1999
Congenitally anomalous uterus Previous low transverse cesarean delivery NA 190 1 per 95 (1.1%) 2 1992-2002 2 Ravasia 1999, Erez 2007
Normal uterus, previous myomectomy NA NA 1,001 1 per 143 (.70%) 7 1930-2006 10 Brown, 1956, Garnet 1964, Dubuisson 2000, Seinera 2000, Nezhat 1999, Seracchioli 2000, Seracchioli 2006, Kumakiri 2008, Sizzi 2007, Makino 2008
Trans-abdominal myomectomy NA 179 1 per 60 (1.7%) 3 1930-1960 2 Brown 1956, Garnet 1964
Laparoscopic myomectomy NA 822 1 per 206(0.49%) 4 1989-2006 8 Dubuisson 2000, Seinera 2000, Nezhat, 1999, Seracchioli 2000, Seracchioli 2006, Kumakiri 2008, Sizzi 2007, Makino 2008
Normal uterus, previous cesarean delivery NA NA 172,397 1 per 236 (0.42%) 732 1983-2002 13 Gardeil 1994, Landon 2004, Lydon-Rochelle 2001, Blanchette 2001, Grobman 2007, Rageth 1999, Miller 1994, Yap 2001, Leung 1993, Kieser 2002, Flamm 1994, Cowan 1994, Lin 2004
Elective repeat cesarean delivery NA 90,360 1 per 623 (0.16%) 145 1982-2002 10 Gardeil 1994, Mozurkewich 2000, Landon 2004, Lydon-Rochelle 2001, Blanchette 2001, Gregory 1999, McMahon 1996, Rageth 1999, Kieser 2002, Lin 2004
TOLAC NA 168,609 1 per 174 (0.58%) 970 1982-2002 22 Gardeil 1994, Mozurkewich 2000, Hibbard 2001, Landon 2004, Lydon-Rochelle 2001, Ravasia 2000, Zelop 1999, Blanchette 2001, Taylor 2002, Grobman 2007, Gregory 1999, McMahon 1996, Rageth 1999, Leung 1993, Kieser 2002, Flamm 1994, Menihan 1998, Phelan 1987, Asakura 1995, Lieberman 2001, Locatelli 2006
History of previous successful VBAC* 71,470 1 per 581 (0.17%) 123 1976-2002 9 Landon 2004, Blanchette 2001, Mercer 2008, Gregory 1999, McMahon 1996, Rageth 1999, Yap 2001, Leung 1993, Asakura 1995
No history of previous successful VBAC 20,191 1 per 125 (0.80%) 161 1983-2002 2 Mercer 2008, Leung 1993
Failed VBAC or repeat cesarean delivery in labor 25,922 1 per



73 (1.4%)



356 1983-2002 5 Landon 2004, Blanchette 2001, Gregory 1999, McMahon 1996, Rageth 1999
Spontaneous TOLAC 29,263 1 per 225 (0.44%) 130 1979-2002 9 Landon 2004, Lydon-Rochelle 2001, Ravasia 2000, Zelop 1999, Blanchette 2001, Delaney 2003, Lin 2004, Locatelli 2006, Molloy 1987
Augmented TOLAC (oxytocin) 15,666 1 per 144 (0.70%) 109 1979-2002 6 Landon 2004, Zelop 1999, Blanchette 2001, Rageth 1999, Molloy 1987, Flamm 1990
Induced



TOLAC (oxytocin)



3,658 1 per 125 (0.80%) 54 1983-2002 5 Landon 2004, Zelop 1999, Blanchette 2001, Taylor 2002, Lin 2004
Induced TOLAC (non-prosta-glandin) 6,768 1 per 125 (0.80%) 54 1983-2002 5 Rageth 1999, Landon 2004, Lydon-Rochelle 2001, Raasia 2000, Bujold 2004
Induced TOLAC (prosta-glandin) 1,817 1 per



63 (1.6%)



29 1984-2002 12 Landon 2004, Lydon-Rochelle 2001, Ravasia 2000, Zelop 1999, Blanchette 2001, Taylor, 2002, Delaney 2003, Lin, 2004, Locatelli 2006, Choy-Hee 2001, Plaut 1999, Wing 1998
Combined prostaglandin-oxytocin induction 924 1 per



58 (1.7%)



16 1984-2000 5 Ravasia 2000, Zelop 1999, Banchette 2001, Taylor 2002, Flamm 1997
Normal uterus, single previous cesarean delivery NA NA 134,556 1 per 196 (0.51%) 686 1975-2000 13 Plauche 1984, Lydon-Rochelle 2001, Zelop 1999, Delaney 2003, McMahon 1996, Rageth 1999, Miller 1994, Macones 2005, Elkousy 2003, Leung 1993, Kieser 2002, Bujold 2002, Asakura 1995
Before labor NA 6,980 1 per 635 (0.16%) 11 1987-1996 1 Lydon-Rochelle 2001
With labor NA 28,698 1 per 173 (0.58%) 166 1984-2002 6 Lydon-Rochelle 2001, Zelop 1999, Delaney 2003, Grobman 2007, Bujold 2002, Lin 2004
Labor induction NA 7,757 1 per 92 (1.1%) 84 1984-2002 6 Lydon-Rochelle 2001, Zelop 1999, Delaney 2003, Grobman 2007, Lin 2004, Locatelli 2006
Successful vaginal delivery 1,110 1 per 1,110 (0.09%) 1 1987-1991 1 Asakura 1995
Classic



midline cesarean delivery



NA 428 1 per



86 (1.2%)



5 1980-2002 4 Chauhan 2002, Landon 2004, Patterson 2002, Bethune 1997
Successful previous vaginal delivery NA 7,070 1 per 244 (0.41%) 29 1984-2002 4 Zelop 2000, Kayani 2005, Grobman 2007, Hendler 2004
No previous vaginal delivery NA 12,805 1 per



93 (1.1%)



137 1984-2002 5 Ravasia 2000, Zelop 2000, Kayani 2005, Grobman 2007, Hendler 2004
Successful previous VBAC NA 526 1 per 526 (0.19%) 1 1988-2002 2 Kayani 2005, Hendler 2004
Low



transverse cesarean delivery



NA 29,501 1 per 142 (0.68%) 208 1984-2002 6 Landon 2004, Shipp 1999, Zelop 1999, Delaney 2003, Bujold 2002, Menihan 1998
With labor 22,855 1 per 143 (0.70%) 160 1988-2002 6 Zelop 1999, Delaney 2003, Grobman 2007, Bujold 2002, Locatelli 2006, Yogev 2004
Spontaneous TOLAC 13,381 1 per 188 (0.53%) 71 1992-2002 4 Delaney 2003, Grobman 2007, Locatelli 2006, Yogev 2004
Induced TOLAC (oxytocin) 3,224 1 per



92 (1.09%)



35 1992-2000 2 Delaney 2003, Grobman 2007
Induced TOLAC (prostaglandin) 724 1 per 241 (0.41%) 3 1992-2002 4 Delaney 2003, Grobman 2007, Locatelli 2006, Yogev 2004
TOLAC with interdelivery interval ≤24 months 1,516 1 per



38 (2.6%)



40 1988-2004 5 Stamilio 2007, Shipp 2001, Bujold 2002, Huang 2002
TOL with 1-layer hysterotomy closure 776 1 per



43 (2.3%)



18 1988-2001 4 Bujold 2002, Durnwald 2003, Gyamfi 2006, Chapman 1997
TOL with 2-layer hysterotomy closure 2,819 1 per 117 (0.85%) 24 1988-2001 4 Bujold 2002, Durnwald 2003, Gyamfi 2006, Chapman 1997
Fetal macrosomia ≥4000 g 2,216 1 per



44



(2.3%)



44 1984-2004 4 Elkousy 2003, Zelop 2001, Jastrow 2010
Multiple gestation With TOLAC 3,289 1 per 137 (0.73%) 24 1985-2007 8 Miller 1996, Myles 2001, Sansregret 2003, Varner 2005, Cahill 2005, Ford 2006, Varner 2007, Aaronson 2010
Multiple gestation Without TOLAC (ERCD) 5,229 1 per 1,1046 (0,10%) 5 1985-2007 5 Miller 1996, Sansregret 2003, Varner 2005, Ford 2006, Aaronson 2010
Fetal macrosomia ≥ 4000 g 2,216 1 per 44 (2.3%) 44 1984-2004 4 Flamm 1989
Gestation beyond 40 weeks 6,746 1 per 77 (1.3%) 88 1984-2002 4 Zelop 2001, Hammoud 2004, Coassolo 2005, Kiran 2006
Induced labor 578 1 per 34 (2.9%) 17 1984-2002 3 Zelop 2001, Hammoud 2004, Coassolo 2005,
Spontaneous labor 1,488 1 per 78 (1.3%) 19 1984-2002 3 Zelop 2001, Hammoud 2004, Coassolo 2005,
Unknown uterine scar NA 3,698 1 per 218 (0.5%) 17 1999-2002 4 Landon 2004, Pruett 1988, Beall 1984, Grubb 1996
Low vertical cesarean delivery NA 1,355 1 per



90 (1.1%)



15 1981-2002 6 Landon 2004, Naef 1995, Adair 1996, Martin 1997, Shipp 1999, Zelop 1999
With labor 933 1 per 104 (0.96%) 9 1981-1997 3 Naef 1995, Martin 1997, Shipp 1999
Normal uterus, multiple previous cesarean deliveries NA NA 6,279 1 per



54 (1.85%)



116 1983-2002 10 Blanchette 2001, Zelop 2000, Caughey 1999, Miller 1994, Macones 2005, Landon 2006,Leung 1993, Cowan 1994, Asakura 1995, Cahill 2010
Spontaneous TOL NA 523 1 per 131 (0.76%) 4 1996-2002 1 Lin 2004
Induced TOL (oxytocin) NA 54 1 per



54 (1.8%)



1 1996-2002 1 Lin 2004
Induced TOL (prosta-glandin) NA 19 1 per



19 (5.3%)



1 1996-2002 1 Lin 2004
NA=Not applicable



TOLAC=Trial of labor after cesarean



VBAC=Vaginal birth after cesarean delivery

[mrsjenrn]

That article is a little confusing because they give several comparisons, and some of them have big and small studies. The graph that didn't show up to well has a really good comparison:

NORMAL UTERUS, PREVIOUS C SECTION:

During an elective repeat c section, 10 studies from 1982-2002 showed a uterine rupture rate of 0.16%

During a Trial of Labor After Cesarean (TOLAC), 22 studies from 1982-2002 show the risk of uterine rupture to be 0.58%.

Both rates are extremely low. Well unfer 1%. What this didn't show was the rate of catastrophic uterine rupture, meaning baby/maternal death, hysterectomy, etc. Of the 0.58%, I believe I read somewhere that 0.02-0.04% of ruptures end really bad. I haven't found the literature on that, so don't take my word for it, but I know it's even lower than the risk of rupture, which as you can see is already small.

[sara76]

Right now the main reason I'm considering a RCS is for the ease of having a tubal.

[mrsjenrn]

My dr said they do a spinal and go through the belly button. Much easier recovery than a c section!

[mrsjenrn]

This is from one of the ICAN leaders on uterine rupture stats.

Data I've seen usually sources Landon, 2004 (n = 17,898):

By Labor Status:
0.4% - Spontaneous labor
0.9% - Augmented labor
1.0% - Induced labor
0.7% - Overall

By Incision Type:
0.7% - Low transverse
2.0% - Low vertical
1.9% - Classical, inverted-T or J
0.5% - Unknown type