When considering delivery options in a patient with a previous Caesarean section, there are ultimately two care pathways for the patient:
- Vaginal birth after Caesarean section (VBAC)
- Planned elective repeat Caesarean
Risks and Benefits of VBAC
Approximately 30% - 35% of women in India will deliver via Caesarean section, and counselling patients about vaginal birth after Caesarean section is becoming increasingly important.
It is known that a planned vaginal birth after Caesarean section is clinically safe for the majority of women who have had one prior lower segment caesarean section (as per NICE, RCOG and ACOG recommendations).
A comparison of the risks associated with VBAC and elective repeat Caesarean section are listed in Table 1 below.
| VBAC | Elective Repeat Caesarean Section |
|---|---|
| If successful, shorter hospital stay and recovery | Longer recovery |
| Risk of uterine rupture – 0.5% to 1 % | Almost negates risk of uterine rupture – less than 0.02% |
| 5% risk of anal sphincter injury | No risk of anal sphincter injury |
| Risk of maternal death – 4 in 100,000 | Risk of maternal death – 13 in 100,000 |
| If successful – good chance of successful future VBACs | Subsequent pregnancies likely to require caesarean section |
| 2-3% risk of transient respiratory difficulties for the neonate | 4-5% risk of neonatal respiratory morbidity |
| Risk of hypoxic ischaemic encephalopathy (HIE) to the neonate – 0.08% | <0.01% risk of neonatal HIE |
| Risk of stillbirth beyond 39 weeks whilst awaiting spontaneous labour – 0.1% | With each caesarean delivery there is increased risk of placental problems (including accreta and praevia), and adhesion formation |
The greatest risk factor for uterine rupture is a previous Caesarean section – monitoring and recognition is a key principle of a VBAC delivery.
The risk factors for uterine rupture in VBAC include:
- Previous Caesarean section – classical (vertical) incisions carry the highest risk.
- Previous uterine surgery – such as myomectomy.
- Induction – (particularly with prostaglandins) or augmentation of labour.
- Obstruction of labour – this is an important risk factor to consider in developing countries.
- Multiple pregnancy
- Multiparity
Key Points
- Women with previous caesarean section have the option of a planned VBAC or elective repeat section.
- VBAC have relatively high success rates and these are even higher if they have had previous vaginal delivery.
- VBAC deliveries are classified as high risk and require close observation and careful management.
- There are both absolute and relative contraindications to VBAC to be aware of.
- Uterine rupture is an emergency that is of critical importance to recognise.