VBAC - Vaginal birth after caesarean.

Information, statistics and references.

There is a saying "Once a caesarean always a caesarean"

This doesn't necessarily have to be the case and women have a choice about the mode of birth after a previous caesarean. In order to make the right choices for themselves women need accurate, current and evidence based information. Below is a summary of current research and guidleines  about VBAC.

-          VBAC is or should be successful 75% of the time


-          While uterine rupture is a real concern for VBAC it is a rare occurrence. (Guise, 2010)There is a 0.64% - 1.2% of a uterine rupture after 1 previous lower transverse caesarean scar in a spontaneous labour, without induction nor augmentation, (that equates to 0.64-1.2  per 100 women). (Landon, 2004; Verhoeven, 2009; Zwart 2009).


-          The risk of an unscarred uterus rupturing is 0.0049% (that’s 4.9 per 10,000 women) in spontaneous labour as compared to 0.64 -1.2%  in a scarred uterus. (Verhoeven, 2009).


-          In an unscarred women uterine rupture rate with induction of labour (IOL) is 0.022% an increase of 44.89% risk of rupture vs spontaneous labour. (Zwart, 2009)


-          Successful VBAC births have fewer complications than repeat caesareans and failed VBACs  (Landon, 2004). However failed VBAC attempts have a higher incident of complications than repeat caesareans.


-          The risks associated with caesareans increase with each caesarean eg. PPH, future placenta praevia and placenta accrete, ICU admissions, hysterectomy, blood transfusions, bladder injuries, thromboembolism & DVT for the mother. (Landon, 2004)


-          The risks associated with caesarean eg PPH, future placenta praevia & accreta, uterine  rupture and/or dehescience reduces after a successful VBAC. (Mercer, 2008).


-          The risk of maternal death is very low in both VBAC and repeat caesareans  0.02% for VBAC  vs. 0.04% for repeat caesarean  (Landon, 2004)


-          Only major/complete/true uterine ruptures are life threatening to mother and baby.


-          A complete true/full or major uterine rupture is a “tear” in the uterus that is full the full thickness of the uterus. It is life threatening to both mother and baby.


-          Uterine dehiscence (incomplete rupture or a window in the uterus) is not a separation of the full thickness of the uterus. It is not life threatening and often is asymptomatic.  It is important when looking at statistics to exclude dehiscence from uterine rupture statistics.  The rate of true rupture and of dehiscence is the same (Landon, 2004)


-          A true uterine rupture is life threatening to baby and the rate for foetal deaths is 6.2% of uterine ruptures (Guise, 2010). This means 6.2% of 0.64% In other words 0.04 per 100 or 4 in 10,000 babies.


-          Uterine ruptures also happen without labour.


-          “While rare for both TOL [trial of labor after cesarean] and ERCD [elective repeat cesarean delivery], maternal mortality was significantly increased for ERCD at 13.4 per 100,000 versus 3.8 per 100,000 for TOL. The rates of maternal hysterectomy, hemorrhage, and transfusions did not differ significantly between TOL and ERCD. The rate of uterine rupture for all women with prior cesarean is 3 per 1,000 and the risk was significantly increased with TOL (4.7 1,000 versus 0.3 1,000 ERCD). Six percent of uterine ruptures were associated with perinatal death. Perinatal mortality was significantly increased for TOL at 1.3 per 1,000 versus 0.5 per 1,000 for ERCD… VBAC is a reasonable and safe choice for the majority of women with prior cesarean. Moreover, there is emerging evidence of serious harms relating to multiple cesareans… The occurrence of maternal and infant mortality for women with prior cesarean is not significantly elevated when compared with national rates overall of mortality in childbirth. The majority of women who have TOL will have a VBAC, and they and their infants will be healthy. However, there is a minority of women who will suffer serious adverse consequences of both TOL and ERCD. While TOL rates have decreased over the last decade, VBAC rates and adverse outcomes have not changed suggesting that the reduction is not reflecting improved patient selection.” (Guise, 2010).




  • Guise, J-M., Eden, K., Emeis, C. Denman, M. Marshall, N., Fu, R.,  Janik, R., Nygren, P., Walker, M., McDonagh, M.(2010). Evidence Report/Technology AssessmentNumber 191 Vaginal Birth After Cesarean: New Insights. Oregon Evidence-based Practice Center, Oregon Health & Science Universit. Portland, Oregon
  • Landon, M., Hauth, J.,  Leveno, K. (2004). Maternal and Perinatal Outcomes Associated with a Trial of Labor after Prior Cesarean Delivery. The New England Journal of Medicine, 351, 2581-2589.
  • Landon, M. B., Leindecker, S., Spong, C., Hauth, J., Bloom, S., Varner, M., et al. (2005). The MFMU Cesarean Registry: Factors affecting the success of trial of labor after previous cesarean delivery. American Journal of Obstetrics and Gynecology, 193, 1016-1023.
  • Landon, M., Spong, C., Tom, E. (2006). Risk of Uterine Rupture With a Trial of Labor in Women with Multiple and Single Prior Cesarean Delivery. Obstetrics & Gynecology, 108, 12-20.
  • Mercer, B., Gilbert, S., Landon, M.,  Spong, C. (2008). Labor Outcomes With Increasing Number of Prior Vaginal Births After Cesarean Delivery. Obstetrics & Gynecology, 11, 285-91.
  • Verhhoeven, C., Ondenaarden, A., Hermus, M., Porath, M., Oei, S., Mol, B. (2009). Validation of models that predict caesarean section after induction of labour. Ultrasound in Obstetrics & Gynecology, 34, 316-321
  • Zwart, J., Richters,J., Ory, F., deVries, J., Bloemenkamp, K., van Roosmalen, J. (2009) Uterine rupture in the Netherlands: a nationwide population-based cohort study. BJOG: An International Journal of Obstetrics and Gynaecology, 116 (8). 1069-1080