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Patricia Janssen, PhD School of Population and Public Health Faculty of Medicine University of British Columbia

• In 2011, the cesarean birth rate in

Canada reached 27.1%, 29% in Ontario and 30.7% in British Columbia.

• Increasingly, women are faced

with the choice to plan a vaginal

• r cesarean birth after a previous

cesarean birth.

• SOGC Guidelines recommend that

planned vaginal birth be offered to women with one previous transverse low-segment cesarean.

• In 2011 Among

women with a previous cesarean birth, the rate of repeat cesarean birth was 81.7% in Canada.

Chi Square test for model fit

In all Health Authorities in BC, the principal predictor of CS is previous CS

• Wen et al. 2004, Canada. n=300,000.
• Uterine rupture 0.65 vs. 0.25 per 100,000

women for TOL vs CS.

• Guise et al. 2010, US. Systematic

review n=402,000.

• Maternal mortality- 0.013% vs.

0.004% for elective repeat CS vs TOL.

• Perinatal mortality -0.13% vs. 0.05%

for TOL vs. elective repeat CS

• Smith et al. 2002, Scotland. Meta-

analysis, n=313,328.

• Perinatal death 12.9 v. 1.1 per 10,000 for

TOL vs. CS

• Mercer et al. 2008. US, n= 13,532.

Significant decrease in the rate of uterine rupture (0.87% vs. 0.45%), for planned vaginal births after at least 1 prior vaginal birth.

• Zelop, 2000. US. n=3,783. Prior

vaginal birth was associated with

• ne fifth of the risk of uterine, 0.2%
• vs. 1.1%.
• Hendler, 2004. US. n=2,204. No

difference in the rates of uterine rupture, 0.5% vs. 1.5%.

• Design
• Retrospective cohort study using

data from the BC Perinatal Data Registry for 2000–2008.

• Inclusion
• 1or 2 prior CS, singleton fetus,

cephalic presentation, term

• Exclusion
• Gestational hypertension, pre-

existing diabetes, cardiac disease excluded.

• Relative risks of planned vaginal vs.

CS calculated using Poisson regression with robust error variance.

• Absolute differences or

attributable risk (AR) reported.

• Number needed to treat (NNT) or

harm (NNH) calculated as the inverse of the AR.

• > 80% power to detect an

absolute difference of 1.0% in our composite outcomes, type I error 0.05, 2-sided.

LIFE THREATENING

DVT Pulmonary embolism Amniotic embolism Uterine rupture Hysterectomy Surgical procedure to control

intrapartum or postpartum bleeding

Blood transfusion Septic embolism Pulmonary, cardiac or CVS

complications from anesthesia

NON LIFE THREATENING

Uterine dehiscence Surgical wound infection Puerperal infection or sepsis Non-life threatening

complications of anesthesia

LIFE THREATENING

Intrapartum stillbirth Neonatal Death Apgar score <3 at 5

minutes

Admission to NICU Need for ventilation HIE IVH

NON LIFE THREATENING

Apgar score 4-6 at 5

minutes

O2 >24 hours Observation nursery Birth trauma

33,812

1 or 2 prev CS

No prior vag delivery 28,406

7,614 (26.8%) planned vag birth

Prior vag delivery 5,406

3,726 (68.9%)planned vag birth

1 = 29,440

3,297 (88.5%) vag

2 = 4,366

4,726 (62.6%) vag

10 20 30 40 50 60 70 80 90 A B C D E F G H J K L M N P

Hospitals with >1000 deliveries in BC, 2007-11, PSBC %

0% 10% 20% 30% 40% 50% 60% 70% 80% 90%

Percent of women who attempted vaginal birth after Cesarean (VBAC) by LHIN of Birth Fiscal 14/15

Attempted VBAC VBAC not attempted

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Attempted VBAC VBAC not attempted

Percent of women who attempted vaginal birth after Cesarean (VBAC) by Level of Care (LOC) Fiscal 14/15

Hospital (level of care 1) Hospital (level of care 2) Hospital (level of care 3)

0% 10% 20% 30% 40% 50% 60% 70% 80% 90%

Percent of women who had successful VBAC among those who attempted VBAC by LHIN of Birth Fiscal 14/15

Yes No

VBAC attempted % VBAC successful %

n = 250

25.2 68.2

n = 346

43.9 71.0

n = 571

26.4 80.7

n = 363

36.0 70.9

n = 2,114

31.5 62.4

n = 59

57.6 58.8

• There were no maternal deaths.
• Composite risk of > 1 life

threatening outcome:

No previous vag > 1 previous vag Pl vag Pl CS RR Pl vag Pl CS RR 165 (2.2) 179 (0.9) 2.52 (2.04-3.11) 73 (2.0) 16 (0.9) 2.06 (1.20-3.52)

Surgical intervention to control bleeding: significantly for women planning vaginal birth

• without a prior vaginal delivery (RR

5.40, 95% CI 3.78–7.72) and

• with a prior vaginal delivery

(RR 7.67, 95% CI 2.40–24.52). Blood transfusion: significantly

• nly for women planning a vaginal

birth

• without a prior vaginal delivery (RR

1.44, 95% CI 1.01–1.72).

Uterine rupture:

• significantly only for women

planning a vaginal birth without a prior vaginal delivery (RR 6.93, 95% CI 3.65–13.16). Uterine dehiscence:

• significantly only for women

planning a vaginal birth without a prior vaginal delivery (RR 2.94, 95% CI 2.04–4.17).

Source: “Self Portrait” by Amanda Greavette

Composite risk of > 1 non-life

threatening outcome:

Source: “Andrea” by Amanda Greavette

No previous vag > 1 previous vag Pl vag Pl CS RR Pl vag Pl CS RR 159 (2.1) 439 (2.1) 0.99 (0.82-1.18) 45 (1.2) 40 (2.4) 0.51(0.33-0.77)

Composite risk of intrapartum

stillbirth, neonatal death, or > 1 life threatening neonatal

• utcome: significantly elevated
• nly for women planning a

vaginal birth without a prior vaginal delivery

No previous vag > 1 previous vag Pl vag Pl CS RR Pl vag Pl CS RR 61 (0.8) 100 (0.5) 1.65 (1.20-2.26) 14 (0.4) 11 (0.7) 0.57(0.25-1.26)

5 minute Apgar < 3:

• significantly only for women

planning a vaginal birth without a prior vaginal delivery (RR 8.85, 95% CI 2.89–27.14). Admission to a neonatal intensive care unit:

• significantly only for women

planning a vaginal birth without a prior vaginal delivery (RR 1.54, 95% CI 1.04–2.26).

Source: “Sleep” by Amanda Greavette

Composite risk of > 1 non-life threatening outcome: significantly for women planning a vaginal birth with a prior vaginal delivery (RR 0.67, 95% CI 0.52–0.86).

No previous vag > 1 previous vag Pl vag Pl CS RR Pl vag Pl CS RR 333 (4.5) 887 (4.4) 1.02 (0.90-1.16) 143 (3.9) 96 (5.9) 0.67 (0.52-0.86)

• 87.1% of women in our sample

had only one previous cesarean birth.

• The direction and size of

differences for each outcome group according to planned mode of delivery was similar to those for the entire sample.

The association between

planned mode of delivery and adverse outcomes after 1-2 previous cesarean births may be modified by history of prior vaginal birth.

Retrospective data. Observational study design. Use of composite outcomes. Smaller sample size of women

with a prior vaginal delivery.

No data on inter-pregnancy

interval or ethnicity.

• Overall, risks for adverse
• utcomes after 1-2 previous

cesarean births are reduced among women with a prior vaginal birth compared to without a prior vaginal birth.

• Absolute differences between

planned vaginal birth compared with planned cesarean birth remain small.

• Our data offer women and their

caregivers the opportunity to consider risk profiles separately for women who have and have not had a prior vaginal delivery.

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