Background Information

Definitions and Choices

Options for delivery are:

• Vaginal birth after previous caesarean delivery (VBAC)
• Elective repeat caesarean section (ERCS)

Risk and Benefit (VBAC vs ERCS)

VBAC

Benefits of VBAC:

• 72-75% success rate
• Fewest complications (if successful)
• Shorter hospital stay and recovery (if successful)

Adverse outcomes associated with VBAC:

• Maternal
  • May result in emergency caesarean delivery 
  • Uterine scar rupture (0.5% risk)
  • Anal sphincter injury (5% risk, related to birthweight)
  • Increased rate of instrumental delivery

• Fetal
  • Slightly higher increased risk of HIE compared to ERCS

VBAC with induction and/or augmented labour has 2-3 fold increased risk of uterine rupture and 1.5 fold increased risk of caesarean delivery.

ERCS

Benefits of ERCS:

• Virtually avoids risk of uterine rupture (<0.02%)
• Reduce risk of pelvic organ prolapse and urinary incontinence

Adverse outcomes associated with ERCS:

• Maternal
  • Longer recovery
  • Likely to require caesarean delivery for future pregnancies
  • Small increased risk of maternal mortality
  • Small increased risk of placenta praevia, placenta accreta, pelvic adhesions

• Fetal
  • Small increased risk of transient respiratory morbidity 

VBAC Guidelines

Suitability

RCOG recommends that planned VBAC is suitable for:

• Most women with ≥37 weeks of singleton pregnancy 
• Who had a single previous lower-segment caesarean delivery
• Regardless of any previous vaginal birth

Contraindications

RCOG absolute contraindications:

• Previous classical caesarean scar (vertical midline scar)
• Previous uterine rupture
• Absolute contraindications to vaginal birth (e.g. placenta praevia)

RCOG advises with caution and is decided by senior obstetricians:

• Complicated uterine scars
• Women who had ≥2 previous lower-segment caesarean deliveries

Intrapartum Care

Deliver in a labour suite in hospital (suitably staffed and equipped delivery suite with continuous intrapartum care and monitoring with resources available for immediate caesarean delivery and advanced neonatal resuscitation)

All women in established CBAC labour should receive:

• Supportive one-to-one care
• IV access with full blood count and blood group and save
• Continuous electronic fetal monitoring 
• Regular monitoring of maternal symptoms and signs
• Regular (no less than 4-hourly) assessment of their cervicometric progress in labour.

Induction and/or labour augmentation should be proceeded with caution if considered necessary due to increased risk of uterine rupture and caesarean delivery.

ERCS Guidelines

Care of ERCS

• Conduct ERCS at 39 weeks of gestation
• Administer antibiotics before skin incision 

References

Original Guideline