6/19/2014

1

To VBAC or Not To VBAC:

What Does the Evidence Say

Angela Wilson-Liverman, MSN, CNM, FACNM

Assistant Professor of OBGYN

Vanderbilt University School of Medicine

angela.wilson-liverman@vanderbilt.edu

Objectives

• Attendees will describe data regarding safety

of TOLAC based on a patient's individual

history

• Attendees will describe evidence-based

counseling for patients regarding TOLAC.

• Attendees will utilize a VBAC calculator to

estimate the likelihood of successful VBAC

Conflicts of Interest

• I have no conflicts to disclose ☺☺☺☺

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2

“The Decision”

Statistics

Statistics• Cesarean delivery rates in America rose to 32

percent in 2007 from 21 percent in 1996.

• Since 1996 one-third of hospitals and one-

half of physicians no longer offer trial of labor

after cesarean (TOLAC).

• The repeat cesarean delivery rate for low-risk

women rose to 89 percent by 2003.

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Statistics

• Success of trials of labor range from 60-80%.

The risk of uterine rupture for spontaneous

labor and one prior cesarean section is < 1%.

• Likelihood of VBAC is associated with

demographic and obstetric factors, with race

and ethnicity the strongest predictors of

success.

Factors affecting success-

Increased probability

• BMI < 30 is associated with higher success rates.

• Nonrecurring indications for the prior cesarean are

also associated with higher success rates (breech or

non-reassuring FHTs)

• Any prior vaginal delivery (before or after the

cesarean) increases chances for VBAC.

• More dilation, effacement, i.e. higher Bishop score

improve chances.

• Spontaneous Labor!

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Factors affecting success

Decreased probability• Latina and African-American women have

lower rates of VBAC than non-hispanic white

women.

• Increasing maternal age, being single, and

having less than 12 years of education are also

associated with lower rates of VBAC.

• Induction or augmentation lower the rate of

VBAC.

Risks of TOLAC vs. Rpt- for

mom

ACOG Practice Bulletin Number 115, August 2010

Benefits for mom• Experience of vaginal birth

• Avoid major abdominal surgery

• Less hemorrhage, infection and shorter recovery

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Risks of TOLAC vs. Rpt- for baby

ACOG Practice Bulletin Number 115, August 2010

Candidates for TOLAC

• ACOG says a “good candidate” is one for

“whom the balance of risk (low as possible)

and chances of success (as high as possible)

are acceptable to the patient and provider.”

• Hmmm…could you be a little more specific,

PLEASE???

Chances of Success and

Morbidity• Studies have demonstrated that women with

a 60-70% chance of VBAC success have </=

maternal morbidity with TOLAC than elective

repeat cesarean delivery (ERCD).

• Women with < 60% chance of VBAC success

have more likely morbidity with TOLAC than

ERCD.60

70

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One Prior Cesarean

• Most women with one prior cesarean with a

low transverse incision are candidates for and

should be counseled about VBAC and offered

TOLAC

• The risk of uterine rupture with one prior

cesarean section and spontaneous labor is

0.5-0.7% (1/150-1/200).

2 or more prior Cesareans• Studies differ with regards to risk of

uterine rupture with greater than one prior uterine incision.

• Rupture risks vary from 0.9-1.8%.

• Maternal morbidity increased

• Similar likelihood of success

• Reasonable to consider as candidates

for TOLAC although data is limited!

Estimated Fetal Weight

• If the EFW is greater than 4000g, likelihood of

VBAC success is lower, especially in women

who had a prior cesarean for dystocia with a

smaller baby.

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Incision Type

• Prior classical uterine incision not

recommended for TOLAC (~5% rupture risk)

• Prior low vertical- similar risk to low

transverse incision

• Unknown- No significant increase in TOLAC

risk. Scar type can often be inferred from

indication. With high suspicion (very preterm

delivery, e.g.) recommend repeat cesarean.

Twin Gestation• VBAC outcomes and success similar to

singleton gestations.

• May be considered for TOLAC per ACOG.

Labor Management TOLAC

• Is Induction or Augmentation OK?

– One study of > 20,000 women found an

increased rupture rate of 0.77% for induced (no

prostaglandins) vs. 0.52% for spontaneous

labors. Prostaglandins increased the rate to

2.24%. (Lydon-Rochelle M., et al 2001)

– Another of > 33,000 women found rates of 0.4%

for spontaneous, 0.9% for augmented and 1.1%

for oxytocin-induced. (Grobman WA., et al 2007)

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Pitocin and TOLAC• Induction or Augmentation have been shown to

increase risk

• Induction beginning with an unripe cervix decreases

likelihood of success

• Patients need counseling when pitocin is considered

or added; “this essentially doubles your rupture risk

from 1/200 to 1/100 (0.5 to 1%)

Misoprostol and TOLAC

• Multiple small studies have shown increased

risk…don’t use it!

Fetal Monitoring and TOLAC

• Often the first indicator of evolving uterine

rupture is changes in the fetal heart rate

tracing (i.e. before pain, bleeding, loss of

fetal station)

• Continuous EFM recommended!

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Foreboding EFM

Foreboding EFM

Interdelivery Interval

• Several studies have shown significantly

increased risk of uterine rupture with short

(< 18 months) interdelivery intervals

• As high as 6% rupture risk

• Believed to be related to scar

healing/integrity

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Counseling Your Patient• Early and Often!

• First prenatal visit history to obtain:

– Complete OB history

– Years of pregnancies, type of deliveries, reason

for C-Section(s), babies’ weights, complications

during pregnancy or delivery

– Request Operative Report

– Solicit TOLAC interest from patient

– Future fertility plans (family size, religious

objections)

Future Fertility PlansTable 1. Risk of Placenta Accreta and Hysterectomy

by Number of Cesarean Deliveries Compared With

the First Cesarean Delivery Column1 Column2 Column3 Column4

Cesarean

Placenta

Accreta Odds Ratio Hysterectomy Odds Ratio

Delivery [n (%)] (95% CI) [n (%)] (95% CI)

First* 15 (0.2) — 40 (0.7) —

Second 49 (0.3) 1.3 (0.7–2.3) 67 (0.4) 0.7 (0.4–0.97)

Third 36 (0.6) 2.4 (1.3–4.3) 57 (0.9) 1.4 (0.9–2.1)

Fourth 31 (2.1) 9.0 (4.8–16.7) 35 (2.4) 3.8 (2.4–6.0)

Fifth 6 (2.3) 9.8 (3.8–25.5) 9 (3.5) 5.6 (2.7–11.6)

Six or more 6 (6.7) 29.8 (11.3–78.7) 8 (9.0) 15.2 (6.9–33.5)

*Primary cesarean delivery.

Abbreviation: CI, confidence interval.

Silver RM, Landon MB, Rouse DJ, Leveno KJ, Spong CY, Thom EA, et al. Maternal morbidity associated with multiple repeat cesarean

deliveries. National Institute of Child Health and Human Development Maternal–Fetal Medicine Units Network. Obstet Gynecol

2006;107:1226–32.

Counseling Your Patient

• Risks/Benefits/Alternatives

• Document the conversation

• Consider using an outpatient

handout/consent form

• Calculate their likelihood of success

to gauge your advice

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Success Prediction

• Consider using a VBAC calculator

• https://mfmu.bsc.gwu.edu/PublicBSC/MFM

U/VGBirthCalc/vagbirth.html

• Accessible through perinatology.com and the

MFMU (Maternal-Fetal Medicine Units

Network)• Grobman WA, Lai Y, Landon MB, Spong CY, Leveno KJ, Rouse DJ, Varner MW, Moawad AH,

Caritis SN, Harper M, Wapner RJ, Sorokin Y, Miodovnik M, Carpenter M, O'Sullivan MJ,

Sibai BM, Langer O, Thorp JM, Ramin SM, Mercer BM; National Institute of Child Health

and Human Development (NICHD) Maternal-Fetal Medicine Units Network (MFMU),

"Development of a nomogram for prediction of vaginal birth after cesarean delivery,"

Obstetrics and Gynecology, volume 109, pages 806-12, 2007.

Prenatal CalculatorVAGINAL BIRTH AFTER CESAREAN

Height & weight optional; enter them to automatically calculate BMI

Maternal age 18

years

Height (range 54-80 in.) in

Weight (range 80-310 lb.) lb

Body mass index (BMI, range 15-75) 25kg/m

2

African-American? no

Hispanic? no

Any previous vaginal delivery? no

Any vaginal delivery since last

cesarean? no

Indication for prior cesarean of arrest

of dilation or descent? no

Calculate

1825nononononoC alc ulate1825nononononoC alc ulate

Prenatal Calculator

• Gives Prenatal likelihood of success with

SPONTANEOUS LABOR

• When counseling your patient prenatally, you

must explain this…

• “If you get to 41 weeks and have not labored

spontaneously, we will have to have a new

and different conversation about options,

risks, etc.”

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Induction or Labor Calculator

Likelihood of Success and

Recommendations• Secondary analysis of MFMU Network study

involving 13,541 women eligible for TOLAC

• When the predicted chance of success was

< 70%, women had MORE morbidity risk

with TOLAC vs. repeat C-Section

• When the chance was > 70%, the risk of

morbidity with TOLAC was LESS than with

repeat C-Section • Grobman et al., 2009.

Example of changed success

prediction• Calculator link

• Case study:

– 34 y.o. A.A. G3P2002 at 37wks EGA; BMI 38

– 1st delivery CSx 8lbs/FTP , 2nd delivery VBAC 8lbs

– Initial counseling/prediction at 12 wk New OB

– Now with gestational htn/needs IOL/cervix 1/th/-

3, med/post

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Case Study

• 18 y.o. G2P1

• BMI 20

• 1 prior Cesarean section for FTP (7cm) 2 years

ago

• Desires TOLAC

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Case Update

• Now she is 40wks EGA

• Diagnosis of Gestational Hypertension

• Cervix 1/thick/-3, vtx

• Considering induction of labor with foley bulb

and pitocin

• Should we induce?

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Case 2

• 30 y.o G3P2002 Latina

• BMI 34

• h/o 1 SVD 2008, 8lb15oz female

And 1 CSx 2011, 7lb 11oz Male (breech)

Should she have a TOLAC?

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References• Grobman, WA, Lai Y, Landon MB, Spong CY, Leveno KJ, Rouse DJ, et al. Can a

prediction model for vaginal birth after cesarean also predict the probability of

morbidity related to a trial of labor? Am J Obstet Gynecol 2009; 200(1):56.e1-

56.e6.

• Grobman WA, Gilbert S, landon MB, Spong CY, Leveno KJ, Rouse DJ, et al.

Outcomes of induction of labor after one prior cesarean. Obstet Gynecol 2007;

109:262-9.

• Guise, JM, Denman MA, Emeis C, Marshall N, Walker M, Fu R, et al. Vaginal birth

after cesarean: New insights on maternal and neonatal outcomes. Obstet Gynecol

2010;115(6):1267-78.

• Landon, MB, Spong CY, Thom E, Hauth JC, Bloom SL, Varner MW, et al. Risk of

uterine rupture with a trial of labor in women with multiple and single prior

cesarean delivery. National Institute of Child Health and Human Development

Maternal-Fetal Medicine Units Network. Obstet Gynecol 2006; 108(1):12-20.

.

References• National Institutes of Health. NIH Consensus Development Conference: vaginal

birth after cesarean: new insights. Consensus Development Conference

statement. Bethesda (MD):NIH;2010. Retrieved from

http://consensus.nih.gov/2010/images/vbac/vbac_statement.pdf

• Tahseen, S., & Griffiths, M. Vaginal birth after two caesarean sections (VBAC-2)-a

systematic review with meta-analysis of success rate and adverse outcomes of

VBAC-2 versus VBAC-1 and repeat (third) caesarean sections. BJOG 2010;117:5-19.

• Vaginal birth after previous cesarean delivery, Practice Bulletin Number 115.

American College of Obstetricians and Gynecologists. Obstet Gynecol

2010;116:450-63.