Safety Comparison of VBAC vs Elective Repeat C-Section

The big question on everyone's mind when deciding whether to choose a VBAC or repeat c-section is:

"What are the risks of a VBAC vs the risks of a repeat c-section?"

Too often, women are sold on repeat c-sections by their doctors who stress the risks of VBAC but gloss over the risks of repeat c-sections

So....  let's put some statistical wording to this...

 

The study by Landon, et al Source 1 (listed below with raw numbers and percentages) shows various risks for VBAC and ERCS.  I am choosing the Landon study to cite since it involved a huge number of women and can give strong statistical significance:

 

Risks of choosing a a TOL (trial of labor) vs an ERCS (elective repeat c-section):

•    More likely to suffer a uterine rupture – the rupture rate in the TOL group (see comments below on the make up of the TOL group)*** was 0.7%; there were no ruptures in the ERCS group, however, women who presented in early labor and did not have a documented intention to labor were excluded so it is possible that women went into labor before their scheduled c-section and ruptured but were excluded from this study’s data

• 1.4 times more like to have a uterine dehisence (typically a benign, thin area in the uterus)

• 1.7 times more likely to need a tranfusion

• 1.6 times more likely to develop endometriosis

• 1.3 times more like to have another adverse event such as (broad ligament hematoma, cystotomy, bowel injury, ureteral injury)

• 1.6 times more likely for the baby to die (doesn't sound like that big of a difference right?  Remember that babies only die in about 2-10% of uterine ruptures according to many studies AND babies do die after c-sections.  In fact, a recent study showed that babies were more likely to die after elective c-sections than planned vaginal births that were not necessarily VBACs)  The absolute risk of neontal death is 0.08% with a TOL vs 0.05% in an ERCS; stated otherwise, the risk of neonatal death is 1 in 1250 babies with a TOL vs 1 in 2000 with an ERCS .
  

Risks of choosing an ERCS over a TOL:

• 1.5 times more likely to need a hysterectomy

• 2.5 times more likely to have a thromboembolic disease (deep venous thrombosis or pulmonary embolism)

• 2 times more likely for mother to die (The absolute risk of death was 0.04% with an ERCS cs 0.02% with a TOL; stated otherwise, 1 in 2500 mothers will die due to an ERCS vs 1 in 5000 mothers will die with a TOL)

• 
  

Risks of a successful VBAC delivery (remember that TOL can end in repeat c-sections) vs an ERCS:

• 1.2 times more likel to need a transfustion

Risks of an ERCS vs a succcessful VBAC:

• 3 times more likely for mother to need a hysterectomy

• 5 times more likely to have a thromboembolic disease (deep venous thrombosis or pulmonary embolism)

• 1.5 times more likely to develop endometriosis

• 4 times more likely for mother to die

***Keep in mind that the TOL (trial of labor group included 17,898 women total):

Those 17,898 included women who had more than 1 previous cesarean and a variety of incision types which could put them at greater risk for uterine rupture/adverse events than most women who attempt VBAC with just 1 prior c-section and a low transverse scar:

Breakdown of the number of previous cesareans:

                 •    16,915 (94.5%) had 1 prior cesarean
                 •    871 (4.9%) had 2 cesareans
                 •    84 (0.5) had 3 cesareans
                 •    20 (0.1%) with 4 cesareans

               8 women had an unknown prior # of c-sections

       

            Breakdown of Incision type:

    •   80.9% (14,483) had a low transverse incision (this is known to be the safest incision type to VBAC with)
    •    0.6% (102) had low vertical incision (2 ruptures  or 2.0%)
    •   17.9% (3206) had unknown type of incision (15 ruptures  or 0.5%)
    •    0.6% (105) had Classical, inverted T or J (2 ruptures  or 1.9%)
    •    0.01% (2) had unclassified (0 ruptures)

Other risk factors that may increase the risk of uterine rupture:

• About 25% of the women in the TOL group had their labors induced (with prostoglandins or pitocin) and/or augmented with pitocin which also increases risk of uterine rupture

• About 25% of the women in the TOL group were less than 2 years from their previous c-section.
  

These risks are a good overall indication of the risk of repeat c-section vs the risk of VBAC; however, your individual risk may be lower depending on your individual situation (management or lack of management of your labor to avoid pitocin and induction agents), length of time between deliveries, whether you've had a vaginal birth, number of previous c-sections, etc)

 

SOURCE 1:

MATERNAL AND PERINATAL OUTCOMES ASSOCIATED WITH A TRIAL OF LABOR AFTER PRIOR CESAREAN DELIVERY
(Landon study, 2004 NEJM)

METHODS:

    * Results obtain from 19 academic medical centers
    * 45,988 women with cesarean history and single gestations included:
       * 17,898 (39%) underwent TOL
        * 15,801 (34%) had elective cesareans
    * 9,013 (20%) had indications for repeat cesarean
    * 3,276 (7%) presented in early labor; intentions unknown

TOL group (n=17,898):

    * 16,915 (95%) had 1 prior cesarean
    * 975 (5%) had more than 1 cesarean:
          o 871 (89%) had 2 cesareans
          o 84 (9%) had 3 cesareans
          o 20 (2%) with 4 cesareans

Maternal Complications

    TRIAL OF LABOR GROUP (n=17,898)
        Complications
            Uterine rupture = 124 (0.7%)
            Uterine dehisence = 119 (0.7%)
            Hysterectomy = 41 (0.2%)
            Thromboembolic disease (deep venous thrombosis or pulmonary embolism) = 7 (.04%)
            Transfusion = 304 (1.7%)
            Endometriosis = 517 (2.9%)
            Maternal Death = 3 (0.02)
            Other maternal adverse events (broad ligament hematoma, cystotomy, bowel injury, ureteral                     injury) = 64 (0.4)
            One or more of the above events = 978 (5.5%)

   

ELECTIVE REPEAT CESAREAN DELIVERY GROUP (n=15,801)
        Complications   
            Uterine rupture = 0
            Uterine dehisence = 76 (0.5%)
            Hysterectomy = 47 (0.3%)
            Thromboembolic disease (deep venous thrombosis or pulmonary embolism) = 10 (0.1%)
            Transfusion = 158 (1.0%)
            Endometriosis = 285 (1.8%)
            Maternal Death = 7 (0.04%)
            Other maternal adverse events (broad ligament hematoma, cystotomy, bowel injury, ureteral                     injury) = 52 (0.3%)
            One or more of the above events = 563 (3.6%)

Maternal Outcomes According to Outcome of Trial of Labor (n=17,898)

    Failed Vaginal delivery (n=4,759)
        Complications
            Uterine rupture = 110 (2.3%)
            Uterine dehisence = 100 (2.1%)
            Hysterectomy = 22 (0.5%)
            Thromboembolic disease (deep venous thrombosis or pulmonary embolism) = 4 (0.1%)
            Transfusion = 152 (3.2%)
            Endometriosis = 365 (7.7%)
            Maternal Death = 2 (0.04%)
            Other maternal adverse events (broad ligament hematoma, cystotomy, bowel injury, ureteral                     injury) = 63 (1.3%)
            One or more of the above events = 669 (14.1%)

   

   Successful Vaginal Delivery (n=13,139)
        Complications
            Uterine rupture = 14 (0.1%)
            Uterine dehisence = 19 (0.1%)
            Hysterectomy = 19 (0.1%)
            Thromboembolic disease (deep venous thrombosis or pulmonary embolism) = 3 (0.02%)
            Transfusion = 152 (1.2%)
            Endometriosis = 152 (1.2%)
            Maternal Death = 1 (0.01)
            Other maternal adverse events (broad ligament hematoma, cystotomy, bowel injury, ureteral                     injury) = 1 (0.01)
            One or more of the above events = 309 (2.4%)

Perinatal Outcomes for Term Infants

    TRIAL OF LABOR GROUP (n=17,898)
        Antepartum stillbirth
            37-38 week = 18 (0.40%)
            > or = 39 weeks = 16 (0.20%)
        Intrapartum stillbirth
            37-38 week = 1 (0.02%)
            > or = 39 weeks = 1 (0.01%)
        Hypoxic-ischemic encephalopathy = 12 (0.08%)
        Neonatal death = 13 (0.08%)
        One or more of the above = 59 (0.38%)

    ELECTIVE REPEAT CESAREAN DELIVERY GROUP (n=15,801)
        Antepartum stillbirth
            37-38 week = 8 (0.10%)
            > or = 39 weeks = 5 (0.10%)
        Intrapartum stillbirth
            37-38 week = 0
            > or = 39 weeks = 0
        Hypoxic-ischemic encephalopathy = 0
        Neonatal death = 7 (0.05%)
        One or more of the above = 20 (0.13%)

STUDY REFERENCE:
NEJM
Volume 351:2581-2589  December 16, 2004  Number 25

Maternal and Perinatal Outcomes Associated with a Trial of Labor after Prior Cesarean Delivery

Mark B. Landon, M.D., John C. Hauth, M.D., Kenneth J. Leveno, M.D., Catherine Y. Spong, M.D.,
Sharon Leindecker, M.S., Michael W. Varner, M.D., Atef H. Moawad, M.D., Steve N. Caritis, M.D.,
Margaret Harper, M.D., Ronald J. Wapner, M.D., Yoram Sorokin, M.D., Menachem Miodovnik, M.D.,
Marshall Carpenter, M.D., Alan M. Peaceman, M.D., Mary Jo O'Sullivan, M.D., Baha Sibai, M.D.,
Oded Langer, M.D., John M. Thorp, M.D., Susan M. Ramin, M.D., Brian M. Mercer, M.D.,
Steven G. Gabbe, M.D., for the National Institute of Child Health and Human Development
Maternal–Fetal Medicine Units Network

Below are some other good sources for comparing the risks of VBAC with the risks of ERCS:

 

SOURCE 2:

Here is a chart from a Candian source comparing the risks of a planned vaginal birth vs a planned c-section:

 

SOURCE 3:

Blog post on the risks of c-section vs risk of VBAC:

Source 4:

The consequences of a planned vaginal birth vs planned c-section from the Lamaze Institute: