VBAC

1. Candidate
Guide
Senior resident guide

2.  Cragin’s dictum,1916 “once a cesarean, always a
cesarean”
 In 1910, Mason and Williams –
 The strength of healed cesarean section scars of
guinea pigs & cats tested by subjecting to increasing
weights.
 Rupture was noted in the muscle but not the scar in
100% cases.
 Kerr’s low transverse uterine incision – 1921 – reduced
maternal mortality from sepsis & hemorrhage
-Gave greater strength to healed incision site

3.  Cragin himself witnessed VBAC in a woman in whom he
did the cesarean NY Med . 1916;104:1–3
 Rethinking the Dictum : Case in 1930s gave an excellent
review on VBAC showing 70% success rate in British
population J Obstet Gynaecol Br Commonw. 1971;78:203–14
 In U.S., till 1970, patients with previous cesarean were
mostly delivered by elective repeat cesarean – leading to
Five-fold increase in rate of cesarean deliveries
 From 1980 onwards, reappraisal of the situation, careful
selection of candidates for VBAC began
 First guideline was formed by ACOG in 1999

4.  Elective repeat cesarean Delivery (ERCD) – Also called
ERCS (Elective Repeat Cesarean Section)
 Trial of labor after cesarean (TOLAC)
This can have 2 outcomes
 Successful TOLAC – Vaginal Birth After Cesarean
Delivery (60 to 80%)
 Failed TOLAC - Emergency cesarean Delivery

5. The available data is limited by 3 important factors
 No Prospective, Randomized trials of TOL V/S ERCD
available so far
 Adverse maternal or perinatal outcomes are rare &
large study populations are necessary to observe a
significant difference in outcomes
 The woman’s choice to attempt a TOLAC is heavily
influenced by her health-care provider & local
resources - leading to selection bias in published
reports

6. -Review previous
medical records &
operative notes,
-Assess risks & benefits

7. Points to be discussed Special considerations
Make patient understand the maternal &
perinatal risks & benefits of VBAC V/S
ERCD
Assess patient’s attitude towards the rare
but serious adverse outcomes
Presence of contraindications to VBAC Any complicating obstetric factors
-Placenta praevia
-Fetal malpresentations
-Cervical fibroid
-Maternal medical disorders
-Previous classical scar
-Previous uterine rupture
-Previous peri-operative complications if any
-Unknown scar, etc.
Likelihood of a successful VBAC Mostly if previous vaginal
birth/successful VBAC
Her plans for future pregnancies
Personal preference & motivation to
achieve vaginal birth or ERCD

9. VBAC ERCD
72- 76% chance of success Able to plan the delivery on a known
date
If successful, shorter hospital stay &
convalescence
Lower risk of vaginal tears & no
worsening of pelvic floor support &
continence mechanisms
Increased likelihood of vaginal delivery
in future pregnancies
Surgical sterilization can be done at the
same time
Lower risk of transfusion (1%) &
endometritis (1.8%) as compared to
failed TOLAC

10. VBAC ERCD
10-15% chance of instrumental delivery
& perineal tear requiring suturing
Increases likelihood of cesarean delivery
in future pregnancy
Failed TOLAC increases maternal
morbidity
Longer hospital stay & convalescence
0.5% of risk of uterine scar rupture –
most dreaded complication
0.1- 2% chances of serious surgical
complications like bladder injury
24-28% of chance of emergency cesarean
delivery
Increased risk of surgical complications
with each subsequent cesarean delivery
due to adhesions, placenta
praevia/accreta
Higher risk of blood transfusion(1.7%) &
endometritis(2%)
No . Of CD Placenta praevia
1 1%
2 1.7%
3 2.3%
>3 2.8%
Any no. 1.2%
No. of CD
AHRQ Publication No. 10-
E003March 2010
Placenta accreta
1 0.3-0.6%( not
significant)
2 or more 1.4%
5 or more 6.74%

11. VBAC ERCD
<1% risk of transient respiratory
morbidity (<ERCD)
Avoids 0.1% risk of antepartum still
birth since delivery is undertaken at
the commencement of 39th week

12. VBAC ERCD
0.1% risk of antepartum still birth
beyond 39 wks while awaiting
spontaneous labor
1-3% risk of transient respiratory
morbidity
0.04% risk of delivery related
perinatal death
0.08% of HIE (Hypoxic ischaemic
encephalopathy) during labor

13.  Largest & most comprehensive Study is conducted by
Landon et al
 Done in women enrolled in NICHD Maternal-Fetal
Medicine Units Network, 1999-2002
 In TOLAC group , n= ~18000
 In ERCD group, n= ~16000
 This study includes all women who had a prior cesarean
delivery & who had a singleton pregnancy at 20 weeks or
more of gestation or whose infant had a birth weight of at
least 500 g
 Women undergoing Cesarean for other indications were
excluded

14. N Engl J Med 2004,351:2581
Complication Trial of labor ERCD Normal labor
Uterine rupture 0.7% 0 0.012%
Gradeil F et al,ur J Obstet Gynecol
Reprod Biol. Aug 1994;
Uterine dehiscence 0.7% 0.5%
Hysterectomy 0.2% 0.3% 0.14% ACOG2002
Thromboembolic
disease
0.04% 0.1%
Transfusion 1.7% 1%
Endometritis 2.9% 1.8% 1-2% Parkland Hospital
Maternal deaths 0.02% 0.04%
Other adverse
events
(broad-ligament
hematoma, cystotomy,
bowel injury, and ureteral
injury)
0.4% 0.3%
Maternal deaths in TOL were 3 in
no. & were due to
1.Severe PIH with hepatic failure
2.Sickle cell crisis with cardiac
arrest
3.PPH
None of them could be directly
attributed to TOL
Hysterectomy in ERCD(47)-
1.Atony(17)
2.Placenta accreta(12)
3.Unexplained hemorrhage(5)
4.Extension / laceration(2)
5.Myoma (3) 6.cancer(5) 7.Others
(3)
Maternal deaths in ERCD
were 7 in no.
Two of them could be
attributed to cesarean
(Hemorrhage & Anesthesia
complications)

15. N Engl J Med 2004; 351:2581–9.
VBAC Failed TOLAC
Uterine rupture 0.1% 2.3%
Uterine dehiscence 0.1% 2.1%
Hysterectomy 0.1% 0.5%
Transfusions 1.2% 3.2%
Endometritis 1.2% 7.7%
Thromboembolic diseases 0.1% 0.02%
Maternal death 0.01% 0.04%
Other maternal adverse
events
0.01% 1.3%
Maternal complications

16. Outcome TOL ERCD
Antepartum
stillbirth
37-38 wk 0.4% 0.1%
39 wk or more 0.2% 0.1%
Intrapartum stillbirth
37-38wk 0.02% 0
39wk or more 0.01% 0
HIE 0.08 0
Neonatal death 0.08% 0.05%
N Engl J Med 2004; 351:2581–9.

18.  Previous 1 LSCS
 Clinically adequate pelvis
 No other uterine scar / previous rupture
 Physician immediately available throughout active
labor, capable of monitoring labor, performing an
emergency cesarean delivery
 Availability of anesthesia & personnel for emergency
cesarean delivery
ACOG practice bulletin 2010

20.  VBAC success rate - 75.3% (in 2 or > previous LSCS)
Uterine Rupture rate – 1.7%
Miller et al. (1994)
 In a meta-analysis,
 VBAC success rate – 71.1% ( Previous 2 LSCS )
 Uterine rupture rate – 1.4%
S Tahseen, M Griffiths -BJOG 2010;117:5–19.
 No conclusive evidence available on methods of induction
or augmentation of labor

21.  Comparison of outcome of trial of labor after previous
two Caesarean sections V/S previous one Cesarean
sections – A Prospective clinical Trial is undergoing
at AIIMS by Dr Prerna under guidance of
Prof Neerja Bhatla
 So far, 2 women with previous 2 LSCS have had
successful Trial of labor
 Both of them were induced with PGE2 (0.5mg) at 39-
40wks

22.  Several studies support VBAC in Twins with a success
rate 69-84%
 Rate of uterine rupture was not found significantly
high - Miller et al and Strong et al
 ACOG 2010 - “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”

23. “ERCD is associated with better perinatal outcome in a
previous LSCS with Breech presentation in current
pregnancy”
-A large multicentric trial by Hannah et al.-
 External Cephalic Version (ECV) is not contraindicated
– ACOG 2010
Flamm BL, Am JObstet Gynecol 1991;165:370–2,
Sela HY, Eur J Obstet Gynecol Reprod Biol 2009;142:111–4
 SOGC (Society of obstetricians & gynaecologists of Canada)
discourages VBAC in Breech

24.  Suspected macrosomia (>4000g) is not a
contraindication for TOL but decreases success rate of
VBAC -Elkousy et al(2003)
 Success rate of 60% is observed
-Zelop et al. Am J Obstet Gynecol 185:903, 2001

25.  No significant difference in the outcome of the next
pregnancy
Chapman et al, Ohel et al, Hauth et al
 Few studies although found increased risk of uterine
rupture, no sufficient data available
Durwald & Mercier, Bujold et al
 Longterm outcomes of CORONIS Trial (A large
randomised multicentre fractional, factorial trial) &
CAESAR Trial (Caesarean section surgical techniques: a
randomised factorial trial) are awaited

26. Other Factors
 Maternal obesity
– Decreases probability of VBAC
- BMI >40 associated with 61% chances of successful VBAC
Hibbard et al, Juhas et al
 History of postpartum fever after Caesarean section
- 3 fold increase in rupture
Shipp T et al Am J Obstet Gynecol.2001;184:S71
 Mullerian duct anomalies
– 8% risk of rupture
Ravasia et al, Am J ObstetGynecol. 1999;181:877–881
 Maternal age - <30yrs (Decrease risk of uterine rupture : 0.5% v/s
1.4%)
Shipp T et al Am J Obstet Gynecol.2001;184:S71.
-Their relationship to the risk of uterine rupture have been examined in
small studies, but definitive conclusions cannot yet be drawn.

27. Related to Previous Cesarean Delivery
 Previous classical or T /J shaped uterine incision
 Previous uterine rupture
 Uterine surgeries involving full muscle thickness
(Hysterotomy, Preterm LSCS, myomectomy with cavity
opened.
 No consistent evidence available for incidence of uterine
rupture in Laparoscopic v/s open myomectomy)
 Previous >2 LSCS (VBAC in previous 3 LSCS has been
reported as early as in1979 but not enough evidence
available)
 Unknown scar – In the absence of previous operative
records, a detailed history may be taken
Most common incision, however is, low transeverse &
VBAC is reasonable Obstet Gynecol.1994;84:255–258

28. Obstetric or Medical complication
 Malpresentation
 Antepartum hemorrhage- Placenta praevia, Placenta accreta
 Severe PIH/eclampsia
 Placental insufficiency (IUGR, Oligohydramnios)
 Medical disorders like HTN, Heart disease, Renal disease,
Asthma, Seizure disorders, Thyroid disorders
(Grobmann et al – Inconsistent evidence, VBAC can be given)
Contracted pelvis/CPD
Inability to perform emergency cesarean due to insufficient
staffing / facilities

30. ACOG practice bulletin 2010
Increased probability of success of TOLAC
Prior vaginal birth
Spontaneous onset of Labor
Decreased probability of success
Recurrent indication for initial cesarean delivery
( Dystocia, CPD)
Increased maternal Age
Nonwhite ethnicity
Gestational age > 40 weeks
Maternal obesity
Pre-eclampsia
Short interpregnancy interval
Increased neonatal birth weight

31.  Factors increasing likelihood of success
Maternal age < 40
Prior vaginal delivery
Favorable cervix, spontaneous labor
Prior cesarean for non recurrent indication
 Factors decreasing likelihood of success
Increased no of prior cesarean deliveries
Gestational age > 40 weeks
Birth weight > 4 kg
Induction or augmentation of labor

32. Factors decreasing risk of failure
 Age <40
 Prior vaginal delivery
 Indication for previous cesarean other than failure of
progress
 Cervical effacement at admission > 75%
 Cervical dilatation at admission > 4cm
Score 0-2 has success rate of 49% & for 8-10, 95%
Flamm ,Obstet gynecol 1994;83:927-32

33.  Grobman & colleagues (2007)
Developed a nomogram to predict a successful TOL
& maternal morbidity based on a questionnaire in
a term gestation with previous 1 LSCS
-A score >60 has a 75-80% chances of a successful
vaginal delivery
Obstetrics and Gynecology, volume 109, pages 806-12, 2007

34. http://www.nialls.com/VBACPred2.aspx

35.  Defined as “A primary cesarean delivery at maternal
request in the absence of any medical or obstetrical
indication”.
(ACOG–American College of Obstetrician and Gynecologists, Committee
Opinion, Number 394, December 2007)
-ACOG states Elective cesareans are justified
options
-FIGO(2003) entails CDMR ‘a positive right of
women’

36.  Lower incidence of endometritis/ transfusions
 Lower Neonatal / Perinatal Morbidity
 Fewer Infant Birth Injuries during Delivery
 Better Maternal Postpartum Satisfaction & Psychological
Wellbeing
 Better Sexual Health in the Immediate Postpartum Period &
in some cases, long term
 Reduced or Avoided Urinary Incontinence & Fecal
Incontinence
 Less damage to pelvic floor, vaginal tearing, episiotomy, and
risk of future pelvic organ prolapse

38.  Take detailed informed written consent
 To be conducted in a suitably staffed & equipped setting
with the facility for emergency cesarean delivery 24x7 &
neonatal resuscitation
 An Obstetrician, Anesthesiologist & pediatrician should be
immediately available
 PGE 2 may be used to induce labor with caution.
 IV access, adequate blood cross matched
 Monitor maternal BP, PR & ST every 15 min

39.  Continuous fetal monitoring by CTG (II A)
 Intrauterine pressure catheters - not routinely useful
 Oxytocin should be used with caution (In AIIMS - low
dose, starting from 1mIU/min is being used for
augmentation)
 No contraindication for epidural analgesia – does not
reduce success or mask signs of rupture
 Regular review of partogram by senior obstetrician
 Routine postpartum exploration of scar - not needed

40.  Most Dreaded complication of TOLAC
 Relative risk of uterine rupture in TOL compared to
ERCD is 2.07
 Maternal and or fetal morbidity of rupture 10-25%
 In rupture, 1.5/10,000 risk of perinatal death &
4.8/10,000 risk of hysterectomy

41.  Uterine rupture – Complete disruption of all layers of
uterus associated with one/more of the following-
 Hemorrhage requiring surgical exploration
 Hysterectomy, Injury to the bladder
 Extrusion of any part of feto-placental unit
 Cesarean delivery for suspected uterine rupture
 Cesarean delivery for fetal distress
 Uterine dehiscence – Asymptomatic uterine disruption
(complete or incomplete) having no effect on mother
or neonate

42.  Most Reliable First sign is - “Non reassuring fetal
heart tracing”
 Most Specific sign is - Persistent variable fetal heart
deceleration.

43.  Classical signs (Unreliable)
 Maternal tachycardia,
 Hypotension,
 Hematuria,
 Pain over previous incision site
 Vaginal bleeding
 Dramatic loss of station
Low sensitivity, high specificity

45. Factors Rate of uterine rupture
Type of scar
Classical 12% ( Rosen et al )
Low transverse (Kerr) 1% (Mc Mohan et al)
Low vertical (Kronig) 0.8%-1.1% (N Engl J Med 2001;345:3–8)
(Adair et al, Shipp et al)
Myomectomy scar with cavity open or
transfundal surgeries
10%
Number of Previous LSCS BJOG 2010;117:5–19
1 LSCS 0.8%
2 LSCS 1.4%

46. Factors Rate of Uterine Rupture
Interdelivery interval Shipp T et al Am J Obstet Gynecol.2001;184:S71
<18 months 2.3%
>18 months 1%
Previous vaginal delivery Zelop et al
Prev 1 LSCS v/s Prev 1LSCS+ vaginal
birth
1.1% v/s 0.2%
Prev 2 LSCS v/s Prev 2 LSCS + vaginal
birth
3.9% V/S 2.5% ( statistically not
significant)
Previous h/o rupture
Lower segment 6%
Upper segment 32%
Factors known at the outset of pregnancy

47. Factors Rate of Uterine Rupture
Macrosomia (>4kg) 1.6% v/s 1% (statistically not significant)
(Obs Gynecol 2003;188(6):516)
Postdatism v/s Term deliveries (Obs Gynecol 2005;(106):700-8)
Spontaneous 1% v /s 0.5%
(Statistically not significant)
Induced 2.6% v/s 2.1%
(statistically not significant)
Preterm Lower rates
Twin pregnancy Similar rates, but 2 fold increased risk of
dehiscence
Breech & ECV Results not definitive

48. Rozenberq P et al , Lancet :1996 ;347(8997):281-4
Lower uterine
segment thickness
Number of
cases
Number of
ruptures
> 4.5 mm 278 0
3.6 – 4.5 mm 177 3 (2%)
2.6 – 3.5 mm 136 14 (10%)
1.6 – 2.5 mm 51 8 (16%)
Current pregnancy characteristics

49. Factors Rate of Uterine Rupture
( v/s Spontaneous Labor )
Oxytocin
Induction 2.3% v/s 0.7%
Augmentation 1% v/s 0.4% ( comparable)
ACOG Committee opinion no:271, apr 2002
Prostaglandin E2 1.3% v/s 0.7% ( comparable)
Prostaglandin E1 5.6%
Intracervical foley’ catheter Safe
Also recommended in second
trimester induction
Mifepristone Under evaluation
Exposure to oxytocin before the active stage of labor
may increase risk of rupture
No co-relation with initial dose, maximal dose, dose
titration, time at maximum dose
Goetzl et al, Obs Gynecol 2001; 97(3):384

50.  Cost of failed TOLAC is more than successful TOL or repeat
cesarean
 If rupture rate > 3.2%, the increased infant
morbidity/mortality of attempted TOLAC exceeded the
benefits of reduced cost
 TOLAC is cost effective if the rate of successful vaginal
delivery >74%
 So careful patient selection is necessary before planning
TOL
Obs Gynecol 2001;97:932-41

51. ACOG practice bulletin 2010
 Most women with previous 1 LSCS are candidates for
VBAC & Should be counseled about VBAC & offered
TOLAC
 Epidural analgesia for labor may be used as part of
TOLAC
 Misoprostol should not be used for 3rd trimester
cervical ripening or labor induction in patients with
previous cesarean delivery or major uterine surgeries
ACOG Guidelines
Level A Evidence

52.  VBAC is recommended in previous 2 LSCS with low transverse
scar and previous 1 LSCS with twins
 ECV for breech is not contraindicated in previous LSCS
 Scars other than low transverse/ low vertical scars or those in
whom Vaginal delivery is contraindicated (eg.placenta accreta)
are contraindications for VBAC
 Induction of labor for maternal/fetal indication remains an
option
 Previous unknown uterine scar is not a contraindication unless
there is high suspicion of classical cesarean delivery
ACOG practice bulletin 2010
There are no areas of significant
difference as compared to RCOG
Guidelines -2007
-RCOG also encourages trial in 3 or
more previous cesarean deliveries