Microsoft word - 4 - vbac may 6_2010 _3_.doc

Risks of Planned Vaginal Birth vs. Planned Cesarean Section
after Previous Cesarean Section
Risks of planned vaginal birth vs.
planned cesarean section after
previous cesarean

Clinical question

What are the risks of planned vaginal birth vs. planned cesarean section after previous cesarean section? Healthy women with previous cesarean section Planned vaginal birth after a) spontaneous or b) induced labour Secondary Outcomes: Maternal transfusion, hysterectomy, maternal infection, maternal mortality, perinatal death or 5 min Apgar <7, admission to NICU.
Search strategy

 Time period: 1990 - 2009  Search terms: Vaginal birth after cesarean, vaginal birth, cesarean section, attempted vaginal birth, trial of labour, uterine scar, uterine rupture.  Databases searched: MEDLINE (Ovid SP); EMBASE; Cochrane CDSR, CENTRAL, DARE, & Geneva Medical Foundation.  Titles reviewed –220; abstracts reviewed – 140; papers reviewed – 96; papers meeting eligibility for inclusion – 25  Exclusions: Studies with misoprostol as primary method of induction
Synthesis of the evidence

The relative risk of uterine rupture for women planning vaginal vs. cesarean birth after a previous cesarean is 2-3 times higher, but the absolute difference is 2-4/1,000. Oxytocin induction compared to spontaneous labour among women Risks of Planned Vaginal Birth vs. Planned Cesarean Section
after Previous Cesarean Section
optimalbirthbc
planning a vaginal birth is associated with a 1.5 – 3-fold increase in risk of uterine
rupture, with a range in absolute increase from 2-9/1,000. Maternal mortality was 0.2-
0.4/1,000 less frequent in the planned vaginal group. Maternal transfusion occurred less
frequently (absolute difference approximately 1-3/1,000 among women planning vaginal
birth but this finding was inconsistent across studies. Hysterectomy (absolute difference
1-2/1,000) and infection (2-40/1,000) were consistently less frequent in the planned
vaginal birth group. Differences in perinatal mortality varied from 0-3/1,000 between
studies in either direction. Newborns of mothers who planned vaginal birth experienced
a reduction in incidence of five minute Apgar scores less than seven and admissions to
NICU ranged from 2-46/1,000.
Limitations

There are major limitations in the evidence related to the safety of planned VBAC vs.
planned C/S:
1. Absence of any randomized clinical trials 2. Inconsistent inclusion criteria, e.g. gestational age, previous vertical incision 3. Inconsistent or lack of definition of uterine rupture 4. Inconsistent outcome definitions, e.g. failure to exclude perinatal deaths due to 5. Oxytocin induction and augmentation protocols are not always provided, and some are not congruent with Canadian practice guidelines 6. Misoprostol is an induction agent in some studies but its use is not recommended in Canada for induction at term with a viable fetus 7. Four of the 5 meta-analyses include studies from the 1980’s when obstetrical practice differed from today’s standards 8. Insufficient power to precisely evaluate risk for rare adverse outcomes including
Conclusions

The risk of uterine rupture among women with a previous cesarean section increases by
2-9/1,000 for those planning vaginal versus cesarean delivery. Risk of uterine rupture
increases when labour is induced, particularly with prostaglandins, to a maximum
reported rate of 15/1,000. Maternal mortality is 0.2-0.4/1,000 less frequent in planned
vaginal versus cesarean birth. Comparisons of perinatal mortality are inconsistent
across studies and vary with differences of 0-3/1,000 in either direction. There is
decreased maternal and newborn morbidity associated with planned vaginal birth.
Overall this review suggests that healthy women at term with a singleton fetus should
be encouraged to plan vaginal birth after a discussion of risk vs. benefit. Induction of
labour should also be offered after a discussion of risk vs. benefit.
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Meta-analysis
Inclusion
Findings
Comments

Rossi, C. et al. 2008
Planned VBAC vs. Planned C/S
Retrospective studies (3)
Uterine Rupture
Maternal morbidity
following a trial of
 intraoperative finding of fetal parts within labour after cesarean
Tan, 2007, Aust-NZ, n= 1,000 Secondary Outcomes:
section vs elective
Prospective studies (4)
 clinical symptoms including abnormal repeat cesarean
Bias, 2001, Europe, n= 252 Maternal morbidity (any type)
delivery: a systematic
Blanchette, 2001, USA, n= 1,481 6.7% vs. 4.0% p= .12 review with meta-
analysis
Landon, 2004, USA, n= 33,699 Transfusion
 intraperitoneal or vaginal hemorrhage n= 42,970
planned VBAC n = 24,349 Hysterectomy
 disruption of the uterine muscles with Inclusion:
 detection of a “window” in the lower bulging or fetal parts visualized through  delivery > 20 weeks gestation or a Maternal morbidity pooled but not defined. Exclusion:
 induction of labour for termination or intrauterine death  studies performed in selected populations (postterm, multiple pregnancy) Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Meta-analysis
Inclusion
Findings
Comments
15 studies, 1989-1999, n=47,682
Planned VBAC vs. Planned C/S
1. All women with elective C/S group were Uterine rupture:
Retrospective cohorts (8)
11/15 studies
Erikson, 1989, USA, n=141 Absolute risk: 0.4% vs. 0.2% Paterson, 1991, UK, n=1059 5/8 prospective cohorts
Elective repeat
cesarean delivery
6/7 retrospective cohorts c) involved extrusion of fetal parts
versus trial of labour:
A meta-analysis of the Obara, 1998, Japan, n=310
literature from 1989 to Swaim, 1998, USA, n=306
Secondary Outcomes:
Prospective cohorts (7)
Maternal mortality:
Phelan, 1989, USA, n=1088 8/15 studies:
Iglesias, 1991, Canada, n=137
Maternal transfusion:
Abitbol, 1993, USA, n=312 7/15 studies:
Flamm, 1994, USA, n=7229 1.1% vs. 1.7%
Granovsky, 1994, Israel, n=52
McMahon, 1996, Canada, n=6138 Hysterectomy:
Rageth, 1999, Switzerland, n=29,046
6/15 studies:
Inclusion:
 spontaneous, induced, augmented Perinatal mortality:
9/15 studies (excluded deaths
Exclusion:
5 minute Apgar <7:
7/15 studies:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Systematic Reviews Inclusion
Findings
Comments

Dodd, J. et al. 2009
n= 698,977
Planned elective
repeat caesarean
excluded Rosen because all studies dated section versus
planned vaginal birth
for women with a
previous caesarean
Inclusion:
Inclusion:
regarding the relative benefits and harms of induction of labour in the presence of a Elective repeat
caesarean section
versus induction of
labour for women
with a previous
caesarean birth
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Systematic Reviews Inclusion
Findings
Comments
Uterine Rupture:
Method of Induction:
Induced vs. Spontaneous labour
Oxytocin: Meehan & Burke; Paul; Flamm,
PGE2: Blanco
The benefits and risks Meehan 1989 n = 289
Flamm, 1987
Oxytocin & PGE2/Misoprostol: Meehan
of inducing labour in
patients with prior
caesaren delivery: a
Flamm, 1997
Measures of association using pooled data systematic review
Total n = 839 1.3% vs. 0.7%
Meehan & Burke
Inclusion:
Exclusion:
Blanchette
medical/obstetrical conditions e.g. preterm or multiple gestation Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Systematic Reviews Inclusion
Findings
Comments
Planned C/S vs. Planned VBAC
The two studies that met inclusion criteria had differences in definitions of outcomes Uterine scar dehiscence:
(only one study reported all outcomes of Abitbol, 1993, USA n = 312 Iglesias:
Inclusion:
Uterine scar rupture:
Vaginal birth after
Abitbol:
Caesarean versus
elective repeat
caesarean for women
Perinatal deaths:
with a single prior
Abitbol:
caesarean birth: A
systematic review of
Apgar <7 @ 5 min:
the literature
Abitbol:
0.8% vs. 4.3%, OR 0.18 (0.02-1.46)
Planned VBAC vs. Planned C/S
n = 56,092
Symptomatic uterine rupture:
Systematic review of
Retrospective studies (2)
2/17 Retrospective/prospective
the incidence and
rupture present. “Asymptomatic uterine consequences of
rupture” for uterine separations without uterine rupture in
Prospective studies (15)
women with previous
caesarean section
Martin, 1983, USA, n=717 Asymptomatic uterine rupture:
Paul, 1985, USA, n=908 3 Prospective studies:
vs.1.3% (0.43-2.62%) 4. Most studies reported only on ToL included for uterine rupture for induction Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Systematic Reviews Inclusion
Findings
Comments
Flamm, 1994, USA, n=5229
Flamm, 1997, USA, n=5022
Case control studies (2)
Connolly, 2001, Ireland, n=26
Leung, 1993, USA, n=140

Case series studies (2)
Bujold, 2002, Canada, n=23
Leung, 1993, USA, n=99
Inclusion:
 spontaneous, induced, augmented
 >1 previous C/S
Exclusion:
 antenatal preeclampsia
 studies conducted in “developing” Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Systematic Reviews Inclusion
Findings
Comments
20 studies, 1982 - 2002; n= 57,363
Planned VBAC vs. Planned C/S
Symptomatic uterine rupture:
9 studies:
Safety of vaginal birth
after cesarean: A
Risk difference 0.27% (0.07-0.47%) 2. The RCTs were for testing other systematic review
Retrospective studies (2)
McMahon, 1996, Canada, n=6138 Secondary Outcomes:
Transfusion: (2 studies)
Prospective Cohort (16)
Meier, 1982, USA, n=269 0.72% vs.1.72% (P=.001) 4. Perinatal deaths did not exclude infants Paul, 1985, USA, n=889 Hysterectomy:
Phelan, 1987, USA, n=2110 0.12% vs. 0.27% (Flamm,1994) Flamm, 1987, USA, n=1776 Duff, 1988, USA, n=227 Maternal Death:
Flamm, 1988, USA, n=1776 0 vs. 0 (McMahon, 1996)
Meehan, 1989, Ireland, n=719
Flamm, 1990, USA n=3957 Blanco, 1992, USA n=81 Raynor 1993, USA n=67 Flamm 1994, USA n=7229 Flamm 1997, USA n=5022 Cowan 1995 USA n=593 Prostaglandin PGE2 in women with
Uterine scar disruption
“Uterine scar” or “wound disruption” previous CS undergoing cervical
PGE2 vs. Spontaneous labour
include: a rent in the integrity of the uterine ripening/induction vs. spontaneous
Cervical ripening and
Uterine scar disruption
labor induction after
10 studies:
Oxytocin vs. Spontaneous labour
uterine scar can also involve serosa with previous cesarean
various degrees of extrusion of intrauterine delivery
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Systematic Reviews Inclusion
Findings
Comments
The term “uterine dehiscence” refers to an opening of the previous uterine scar with visualization at laparotomy, or detected Total n = 12,779

PG2 Gel n =1,682
Spont. labour n = 11,097

Oxytocin in women with previous
CS undergoing cervical ripening/in
duction vs spontaneous labour
5 studies:
Molloy, 1987 n = 1480
Lao, 1987 n = 666
Ravasia, 2000 n = 1971
Bebbington, 2000 n = 3050
Fleishman, 2000 n = 684
Total n = 7851

Oxytocin n= 1566
Spontaneous. labour n = 6285
Inclusion:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Prospective
Outcomes
Comments
Cohort Studies
No Prior Vaginal Delivery/Birth (VB) vs. prior vaginal
n = 11,778
Uterine Rupture:
Outcomes of
induction of labour
Induced vs. Spontaneous Labour
after one prior
No prior VB: 1.5% vs. 0.8% OR 1.84 (1.11-3.05)
cesarean
Inclusion:
Prior VB: 0.6% vs. 0.4% OR 1.39 (0.62-3.13)
No oxytocin or prostaglandin:
No prior VB: 0 vs. 0.8% p= 1.00
Prior VB: 0 vs. 0.4% p= 1.00
Prostaglandin only:
Exclusion:
No prior VB: 0 vs. 0.8% p= 1.00
 antepartum intrauterine demise Prior VB: 0 vs. 0.4% p= 1.00

Oxytocin without prostaglandin:
No prior VB: 1.8% vs. 0.8% OR 2.19 (1.28-3.76)
Prior VB: 0.6% vs. 0.4% OR 1.53 (0.66-3.54)

Oxytocin with prostaglandin:
No prior VB: 1.2% vs. 0.8% OR 1.47 (0.57-3.76)
Prior VB: 0.5% vs. 0.4% OR 1.17 (0.16-8.86)
Secondary Outcomes (Induced vs. Spontaneous)
Endometritis
No prior VB: 3.8% vs. 3.7% OR 1.03 (0.77-1.38)
Prior VB: 1.3% vs. 1.8% OR 0.72 (0.43-1.18)
Blood Transfusion
No prior VB: 2.3% vs. 1.4% OR 1.65 (1.10-2.48)
Prior VB: 1.2% vs. 1.1% OR 1.13 (0.66-1.95)
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Prospective
Outcomes
Comments
Cohort Studies
Hysterectomy
No prior VB: 0.4% vs. 0.1% OR 3.92 (1.10-13.9)
Prior VB: 0.1% vs. 0.1% OR 0.873 (0.18-4.34)

Composite Maternal Morbidity
No prior VB: 2.5% vs. 1.4% OR 1.78 (1.20-2.65)
Prior VB: 1.2% vs. 1.1% OR 1.11 (0.65-1.90)
Apgar score < 4 @ 5 minutes
No prior VB: 0.4% vs. 0.2% OR 1.96 (0.68-5.64)
Prior VB: 0.3% vs. 0.2% OR 1.50 (0.44-5.14)
Umbilical cord artery pH < 7.0
No prior VB: 1.9% vs. 2.0% OR 0.97 (0.49-1.94)
Prior VB: 1.5% vs. 1.2% OR 1.23 (0.48-3.17)

NICU Admission
No prior VB: 9.6% vs. 9.4% OR 1.03 (0.85-1.24)
Prior VB: 8.6% vs. 7.4% OR 1.19 (0.-1.47)

Intrapartum or neonatal death
No prior VB: 0.12% vs. 0.07% OR 1.74 (0.29-10.4)
Prior VB: 0.2% vs. 0.02% OR 7.90 (0.82-76.0)
Planned VBAC vs. Planned C/S
Uterine Rupture: 0.7% vs. 0.05%
n = 39,117
Uterine dehiscence: 0.7% vs. 0.5%
Risk of uterine
rupture and adverse
Secondary outcomes:
Perinatal outcome at
Hysterectomy: 0.2% vs. 0.4%
term after cesarean
Inclusion:
Transfusion: 1.5% vs. 1.3%
delivery.
Endometritis: 2.9% vs. 2.3%
Maternal death: 0.01% vs. 0.03%
Neonatal death: 0.08% vs. 0.08%
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Prospective
Outcomes
Comments
Cohort Studies
Planned C/S vs. Planned VBAC
Secondary Outcomes
Planned cesarean
n = 18,653
RR for Planned C/S
versus planned
Apgar 5 min <7: 0.4% vs. 1.0% 0.37 (0.12-1.16)
vaginal delivery at
Apgar 5 min <4: 0.2% vs. 0.3% 0.88 (0.22-3.62)
term: Comparison of
Transfer to NICU: 9.8% vs. 5.2% 1.87 (1.51-2.32)
newborn infant
Inclusion:
Pulmonary disorder:
outcomes
Abnormal neurological status:
Intracranial hemorrhage:
Exclusion:
Neonatal convulsions :
0.1% vs. 0.2% 0.75 (0.10-5.46)
Bacterial infection: 0.5% vs.0.8% 0.63 (0.23-1.69)
Planned VBAC vs. Planned C/S
New England Journal of the USA,1999-2002 Uterine Rupture (Spontaneous labour):
n = 45,988
Maternal and perinatal ToL n =17,898
outcomes associated
Uterine Dehiscence (Spontaneous labour):
with a trial of labour
after prior cesarean
Planned VBAC inclusion:
delivery
Uterine Rupture: Type of labour vs. spontaneous
Augmented vs. spontaneous
Induction (all) vs. spontaneous:
Any prostaglandin/with or without oxytocin vs.
spontaneous:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Prospective
Outcomes
Comments
Cohort Studies
Planned C/S inclusion:
Prostaglandins alone vs. spontaneous:
Mechanical induction with/without oxytocin vs.
spontaneous:
Oxytocin alone vs. spontaneous:
Secondary Outcomes: (Combined)
Exclusion:
Planned VBAC vs. Planned C/S
Transfusion: 1.7% vs. 1.0% OR 1.71 (1.41-2.08)
Hysterectomy: 0.2% vs. 0.3% OR 0.77 (0.51-1.17)
Endometritis: 2.9% vs. 1.8% OR 1.62 (1.40-1.87)
Maternal death: 0.02% vs.0.04% OR 0.38 (0.10-1.46)
Neonatal death: 0.08% vs.0.05% OR 1.82 (0.73-4.57)
HIE: 0.08% vs.0 p=<0.001
Planned C/S vs. Planned VBAC
Admission NICU: 9.3% vs. 4.9% p=0.025
Neonatal outcomes
after elective
cesarean delivery

Inclusion:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments 
Cohort Studies
Kamath cont.

Exclusion:
Planned VBAC vs. Planned C/S
Uterine Rupture:
Spontaneous labour vs. EC/S
Rupture of scarred
Planned CS n=588 Oxytocin induction vs. EC/S
Planned VBAC n=1540 1.4% vs. 0.3% OR 4.0 (0.3-55.6)
Spontaneous labour n=1074
Oxytocin induction n=148
Prostaglandin induction vs. EC/S
Cervical ripening –PG2 n=318 2.2% vs. 0.3% OR 6.6 (1.2-65.3)

Inclusion:

Exclusion:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments 
Cohort Studies
Cahill, A. et al. 2006
Planned VBAC vs. Planned C/S
Uterine Rupture
Is vaginal birth after
0.4% vs. 0.06% Unadj OR 6.26 (0.84-46.6) cesarean (VBAC) or
Prior vaginal delivery n = 6619
elective repeat
cesarean safer in
Composite outcome (uterine rupture, bladder or 
women with a prior
bowel injury, or uterine artery laceration)
vaginal delivery?
Inclusion:
* Adjusted for number of prior uterine scars, labor Exclusion:
Postpartum fever
* Adjusted for gestational age at delivery, diabetes mellitus, preeclampsia, gestational hypertension Blood transfusion
* Adjusted for gestational age at delivery, preeclampsia, Planned VBAC vs. Planned C/S
Uterine Rupture
Previous CS n = 1308
Results of a well-
Planned C/S n = 467 Secondary Outcomes
defined protocol for a
Inclusion:
Major complications (hysterectomy, relaparotomy,
trial of labor after
uterine rupture, operative injury, > 2 unit trans.)
prior cesarean
delivery
Minor complications (febrile morbidity, abdominal
wound infection, 1 unit blood transfusion, uterine
scar dehiscence
Neonatal ICU Admissions
2.4% vs. 4.3% p =.055
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments
Cohort Studies
Induction with previous C/S vs. Intact uterus
Uterine Rupture: 0.3% vs. 0.02% p = 0.22
P = 0.16, OR 10.3 (0.7-143.1) when adjusted for Induction/ previous CS n = 310 maternal age, nulliparity, gestational age at delivery, Induction of labour:
bishop score, duration of labour, use of PG gel or Comparison of a
oxytocin, and birth weight (rates not provided). cohort with uterine
Inclusion:
scar from previous
Secondary Outcomes:
cesarean section vs. a
cohort with intact
Apgar score < 7 at 5 min.: 0.3% vs. 0.5% p = 0.93
Umbilical artery pH < 7: 0.3% vs. 0.5% p = 0.46
Exclusion:
Induction protocol for women with one previous CS
 Cervical ripening with intracervical PGE2 gel 0.5 mg every 8 hours OR intravaginal PGE2 gel, 1 mg every 12 hours until a bishop score of >6 or a maximum of 4 doses. When BS >6, ARM done, and oxytocin  Oxytocin infusion started at 1.3-2.6 mu/min and doubled every 40 mins. to a maximum of 42 mu/min.
Induction protocol for women with intact uterus
 Cervical ripening with intracervical PGE2 gel 0.5 mg every 6 hours until a bishop score of >4 or a maximum of 2 doses. When BS >4, intravaginal PGE2 1 mg for nullip and 2 mg for multips for a maximum of two doses. After two doses or when BS > 6, ARM done, and oxytocin started 2 hours later if not in labour.  Oxytocin infusion started at 1.3-2.6 mu/min and doubled every 40 mins. to a maximum of 42 mu/min. (same protocol as for previous CS) Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments
Cohort Studies
Attempted VBAC vs. Elective CS
Uterine rupture: 0.9% vs. 0.004% RR 21.1 (8.6-51.5)
Maternal
Secondary outcomes:
complications with
Blood transfusion: 0.7% vs. 1.2% RR 0.58 (0.45-0.75)
vaginal birth after
Postpartum fever: 9.4% vs. 13.0% RR 0.73 (0.68-0.78)
cesarean delivery: A
multi-centre study
n= 25,005
Inclusion:
 > 1 previous CS
Exclusion:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments
Cohort Studies
Attempted VBAC vs. Elective CS
Uterine rupture: 0.8 % vs. 0
Vaginal birth after
Secondary outcomes:
cesarean delivery:
Chorioamnionitis: 5.9% vs. 0 p = < 0.0001
predicting success,
Postpartum fever: 5.2% vs. 2.4% p = 0.09
risks of failure.
Inclusion:
Endometritis: 4.6% vs. 2.0% p = 0.10
NICU admission: 7.5% vs. 6.5% p = 0.76
5 min Apgar < 7: 2.3% vs. 0 p = 0.01
liveborn, singleton infant by primary low transverse CS
Exclusion:
upper uterine segment or conversion to a T-incision at the time of low transverse CS intervening viable pregnancy at another institution other than the study institution Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments
Cohort Studies
Attempted VBAC vs. Elective CS
Uterine rupture: 0.4 % vs. 0 p = 0.5
Secondary outcomes:
Maternal and neonatal Elective CS n = 481
Transfusion: 1.3% vs. 0.6% p = 0.2
morbidity after
Infection: 2.5% vs. 2.3% p = 0.8
elective repeat
Inclusion:
NICU admission: 4.2% vs. 5.6% p = 0.2
cesarean delivery
Neonatal death: 0.1% vs. 0.2% p = 0.6
versus a trial of labor
after previous
cesarean delivery in a
community teaching
hospital.
Planned VBAC vs. Planned C/S
Uterine rupture (total study population):
Comparison of
n = 308,755
maternal mortality
and morbidity
Uterine rupture (Induced vs. spontaneous labour):
between trial of
labour and elective
Inclusion:
cesarean section
Secondary Outcomes:
among women with
*Adjusted OR
previous cesarean
Transfusion 0.19% vs. 0.15% OR 1.67 (1.39-2.00)
delivery
Exclusion:
Hysterectomy 0.1% vs. 0.08% OR 1.26 (0.99-1.61)
PP Infection 0.38% vs. 0.47% OR 0.81 (0.77-0.97)
In-hosp Death 1.6 vs 5.6/100,000 OR 0.32 (0.07-1.47)
* Adjusted for year of birth, hospital volume, & mat. age. Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments
Cohort Studies
Induced vs. Spontaneous labour
Uterine rupture: 0.7% vs. 0.3% p= .13
Uterine scar defect: 0.5% vs. 0.3% p=.50
Spontaneous versus
induced labour after a
Secondary Outcomes:
previous cesarean
delivery
Transfusion: 0.6% vs. 0.5% p= .58
Inclusion:
Hysterectomy: 0.2% vs. 0.1% p= .20
Maternal infection : 3.4% vs. 2.8% p= .36
NICU Admission: 13.3% vs.9.4% p=.001
Neonatal death: 0.2% vs.0.2% P= .68 (antepartum
and intrapartum deaths discussed, but reasons for Exclusion:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Retrospective
Findings
Comments
Cohort Studies
Planned C/S vs. Planned VBAC
Uterine Rupture: OR for Planned VBAC
Failed vaginal birth
All disruption: 0.5% vs. 1.1% 2.29 (0.52-10.1)
after a cesarean
Dehiscence: 0.5% vs. 0.3% 0.65 (0.12-3.56)
section: How risky is
True rupture: 0.0% vs. 0.8% Not calculated
Inclusion:
Secondary Outcomes: OR for Planned VBAC
PPH> 1,000 ml: 7.4% vs. 3.5% 0.45 (0.28-0.71)
Transfusion: 1.4% vs. 0.8% 0.59 (0.22-1.62)
Hysterectomy: 0.0% vs. 0.5% Not calculated
Chorioamnionitis: 4.2% vs.12.8% 3.41 (2.06-5.66)
Endometritis: 8.8% vs. 8.2% 0.93 (0.63-1.36)

Exclusion:
Planned VBAC, vs. Planned C/S
n = 20,095
Uterine rupture:
Risk of uterine
Spontaneous labour
rupture during labour
among women with a
prior cesarean
Induced without prostaglandin:
delivery.
Inclusion:
 spontaneous & induced labour Induced with prostaglandin:
Risks of Planned Vaginal Birth vs. Planned Cesarean Section after Previous Cesarean Section
optimalbirthbc
Primary Outcome: Uterine Rupture / Dehiscence in Women with a Prior Cesarean Section, by Type of Labour
Author
Induced (method unspecified)
Oxytocin only vs Spontaneous
PGE2/PEG1 only vs Spontaneous
Oxytocin with PG/Miso vs
vs Spontaneous labour
Labour (unless otherwise indicated)
Spontaneous Labour
Systematic Reviews
Blanco: 0 % vs. 0 % Flamm,
McDonagh, M., 2005
Blanchette
Sanchez-Ramos, 2000
disruption
Uterine scar disruption
Prospective Cohorts
No prior VB:
No prior VB:
No prior VB:
Grobman, W. et al.
Prior VB:
Prior VB:
Prior VB:
Landon, M. et al. 2004
Uterine Dehiscence
Augmented vs. spontaneous
Retrospective Cohorts
Oxytocin induction VBAC vs. EC/S
Prost. induction VBAC vs. EC/S
Grossetti, D. et al. 2007
Wen S. et al. 2004
Delaney, T. et al. 2003
Uterine rupture:
0.7% vs. 0.3% p= .13
Uterine scar defect:
0.5% vs. 0.3% p=.50
Lydon-Rochelle, M. et
Medical Induction VBAC, vs.
Prostin Induction vs. Planned C/S
Planned C/S

Source: http://optimalbirthbc.ca/wp-content/uploads/2013/08/4-VBAC-May-6_2010-_3_.pdf