In an effort to keep our organization up to date, please take a moment to complete our short survey. There are so little studies available, keeping our own data is very powerful. Also, please keep in mind some of these studies are quite dated. However, knowledge is power and access to information is where it begins. Feel free to brown the studies below to help answer any questions you may have. 

Another insightful document, is ACOG’s VBAC bulletin.  Knowing and understanding the document can be useful, especially when it comes to discussing delivery options with your provider. The most recent bulletin is from November 2017. In addition, ACOG’s recent committee opinion on medically-indicated early c-sections lays out some of the rationale for this practice when a special scar is present. 

2005 – de Costa – VBAcC Review

This is a historical review of studies that looked at risk of rupture after a classical cesarean.

Certainly the literature suggests that some classical scars might be more prone to rupture than others. However the risk of rupture of a single well-healed classical Caesarean section scar during a subsequent TOS (Trial of Scar) cannot be determined from any of the studies cited above. It does appear that where there has been no postpartum febrile morbidity and where the placenta in both the current and Caesarean section pregnancies has not been sited under the incision, the risk of rupture for a woman attempting vaginal birth after a single classical Caesarean section might be not much greater than that associated with TOS following one lower segment Caesarean section, and might be similar to that for TOS after two lower segment Caesarean sections, now an acceptable practice. It might also be that in many cases, the scar of a prior classical Caesarean section has already shown its strength by reaching the point of spontaneous labour intact.

Landon et al 2004

This study is the most recent study that includes any information about the risk of rupture for classical, inverted T and J incisions.

Two uterine ruptures were recorded in 105 women (1.9 percent) with a prior classical, inverted T, or J incision who either presented in advanced labor or refused a repeated cesarean delivery.

2004 – Lin and Raynor

The original purpose of this study was “to determine the risk of uterine rupture in patients induced with oxytocin or misoprostol after 1 or more previous cesarean sections.” No uterine ruptures occurred in patients with classical or low vertical scars.

Shipp et al 1999

This study compared the risk of rupture between TOLs after low transverse incisions and low vertical incisions. Conclusion: Gravidas with a prior low vertical uterine incision are not at increased risk for uterine rupture during a trial of labor compared with women with a prior low transverse uterine incision.

Sciscione et al 2008

The objective of this study was to determine if women with a history of a previous preterm cesarean delivery experienced an increased risk of subsequent uterine rupture compared with women who had a previous nonclassic term cesarean delivery. Conclusion: Women who have had a previous preterm cesarean delivery are at a minimally increased risk for uterine rupture in a subsequent pregnancy when compared with women who have had previous term cesarean delivery.

Patterson et al 2002

The objective of this study was to estimate the maternal and perinatal morbidity associated with cesarean delivery involving the upper uterine segment compared with that of low transverse cesarean delivery.

Conclusion: Classic cesarean section has a higher maternal and perinatal morbidity than inverted T cesarean and much higher than low transverse cesarean. There is no increased maternal or perinatal morbidity if an attempted low transverse incision has to be converted to an inverted “T” incision compared to performing a classic cesarean section.

Chauhan et al 2002

This is a retrospective study of 157 women who had a pregnancy after a classical c-section. All had repeat c-sections, with .6% rupture and 9% asymptomatic dehiscence and no correlation between scar separation and cervical dilation at time of c-section. The most recent American College of Obstetricians and Gynecologists practice bulletin on vaginal birth after previous cesarean delivery quotes a 4-9% risk of uterine rupture in the subsequent pregnancy of patients with prior classic cesarean surgery. This figure is correct for combined uterine ruptures and dehiscences but overstates the occurrence of actual uterine rupture in this special patient population.

Landon and Lynch 2011

This is a literature review for both classical and myomectomy scars. The conclusion for classical scars is that scheduled c-section at 36-37 weeks is a reasonable option. For myomectomy scars, they concluded the risks are comparable to low transverse c-section scars. For both sets of scars, authors acknowledge a lack of well-designed studies to formalize conclusions.

Landon 2010

Another literature review looking at various risk factors that may contribute to uterine rupture.

Suster and Gergolet 2016

A study on pregnancy after metroplasty for uterine septate.

Alphen et all 1995

Ultrasound used to diagnose recurrent uterine rupture.

Stotland et all 2002

Delivery strategies for women wit a previous classic CS.

Pare et al 2005

Vaginal birth versus elective repeat CS: an assessment of maternal downstream health outcomes.

Bailit et al 20016

Impact of time of day on CS complications.

Gonen et al 2006

Protocol for trial of labor for VBAC.

Silver et al 2006

Maternal morbidity associated with multiple repeat cesarean sections.

Lowe 2007

A review of factors associated with dystocia and c-sections in nulliparous women.

Sawyer 2007

A lecture titled: Cesarean Section for the Non-Obstetrician.

Shim 2008

Overview: Discuss the risks of VBAC; Review the change of statistics for C/S and VBAC; Review the change of guidelines for VBAC; Discuss the risk assessment tools for successful VBAC; Discuss the strategies to reduce the overall C/S rate.

Zwart 2008

Objective: To assess incidence of uterine rupture in scarred and unscarred uteri and its maternal and fetal complications in a nationwide design (in the Netherlands).

Goumalatsos 2009

Around 10% of the obstetric population have experienced prior Caesarean delivery. This article provides a practical evidence-based approach to the antenatal and intrapartum management of such women. A gestationspecific strategy is suggested. Women with an uncomplicated pregnancy and single previous lower segment Caesarean delivery may be managed in shared community care following counselling by a consultant midwife. It is important to provide complete informed consent detailing the risks and benefits for the woman that are individualised to her circumstances. It is estimated that planned vaginal birth after Caesarean exposes the woman to an additional 0.25% risk (or 1 in 400) for experiencing an adverse perinatal outcome (antepartum stillbirth, delivery-related perinatal death or hypoxic ischaemic encephalopathy) compared with opting for elective repeat Caesarean section (ERCS). It is likely that this risk is significantly reduced for women who opt for ERCS at the start of the 39th week; however, direct evidence to support this is lacking.

Bakhshi et al 2010

Maternal and neonatal outcomes of repeat cesarean delivery in women with a women with a prior classical versus low tranverse uterine incision.

Dekker et al 2010

Risk of uterine rupture in Australian women attempting vaginal birth after one prior caesarean section: a retrospective population based cohort study.

Spong et al 2011

Timing if indicated late-preterm and early term birth. Justifications for early c-section with classical or myomectomy scars.

Uterine Rupture in Pregnancy

A detailed review of risk factors for rupture, including most of the known special scars.

Pregnancy Outcome and Uterine Fibroids

Pregnancy outcomes, both with fibroids present and post-myomectomy.