What is a VBAC ?

July 19, 2019

Women who’ve had caesarean births are usually physically able to try vaginal birth next time around. This is commonly called vaginal birth after caesarean or “VBAC”.

Up to 1 in 4 women in Australia has delivered a baby via caesarean section. In the past it was generally assumed that once a women had a caesarean section birth then all future babies would be delivered via the same mode caesarean section.

Thanks to medical advances in obstetrics many women have safely delivered their subsequent babies vaginally or by ‘VBAC’.

It is important to remember that every individuals’ preferences and risk factors will be different. 

What is most important is the safety and wellbeing of both you and your baby.

In planning this together we can ensure that your experience is a positive one.

Things to consider about a future VBAC:

If you are considering a VBAC for your next pregnancy it is a great idea to discuss this with your treating doctor/ medical staff.

For my patients we can discuss this at our first visit and revisit this throughout the pregnancy and discuss the suitability.

The reason we do this as there are a few factors to consider about VBAC delivery;

• Location of the previous uterine scar
• Are there  any current pregnancy complications
• Reason for previous caesarean section
• Time lapse since previous caesarean section ( higher risk of rupture if <2 years)
• Type of previous uterine incisions ie  low transverse, classical vertical or horizontal, inverted T – shape 

Possible Benefits of VBAC

• Shorter recovery and shorter hospital stay
• Lessened abdominal pain after birth as opposed to caesarean section
• A great chance of uncomplicated vaginal births in future pregnancies
• Avoid the risks associated risks of major surgery
• Faster mobility following the birth of your baby as opposed to caesarean section

Reasons why a VBAC is Not Suitable

In some instances a VBAC is note a suitable mode of delivery and a repeat caesarean delivery will be the safest choice for both you and your baby.  

These reasons include:

• 3 or more previous caesarean section deliveries
• Previous uterine rupture
• Previous High ‘classical’ uterine incision
• Baby is in Transverse position (lying across the uterus)
• Previous gynecological surgery such as Fibroid removal
• Unfavorable cervix following induction of labour
• Obesity (your body mass index is 30 or higher)
• Pre-eclampsia (high blood pressure during pregnancy)
• Age (usually older than 35)
• Your previous caesarean was within the last 2 years
• The Baby is very measuring large and unable to pass through birth canal
• A know medical condition which complicates labour
• Placenta Previa (placenta lies across the cervix)
• Unusual pelvic shape

Factors which affect the Success of a VBAC

There are a number of factors which suggest a successful VBAC, these include;

• previous successful VBAC
• Spontaneous onset of labour
• Previous vaginal birth
• A risk free uncomplicated pregnancy 

There are also a few factors that ‘lessen’ the success of a vaginal birth, these include;

• BMI greater than > 30
• A complicated pregnancy
• Never had a previous vaginal birth
• Induction of labour  
• Slow progress in past labour   

Induction of Labour and VBAC

If you don’t go into labour and are planning a VBAC for my patients we will discuss the options should this scenario arise on and individual basis. Whilst this still remains an option this may reduce the success rate of achieving a VBAC. Induced labour is less likely than spontaneous labour to result on VBAC due to unfavorable cervix and failure to progress or fetal distress ultimately resulting in caesarean section.

 Risks associated with VBAC

Whilst uncommon nothing is without its risks and it is important to be fully informed of all possible outcomes associated with having a VBAC.

• Uterine scar rupture (1 in every 200 attempts) this is uncommon but a serious complication

• Higher change of emergency caesarean section during labour increasing the possible risk of bleeding & infection in comparison to a planned caesarean section

How will be your care during labour be deferent if you have a VBAC? 

Continuous monitoring of your baby’s heart rate is recommended once you are in established labour. This may help to detect any changes in the baby’s heart rate, which may be related to problems with the scar on your uterus (womb).

Sometimes you may need to have an intravenous cannula inserted so that blood can be taken and cross-matched in case an emergency. The progress of your labour will be closely monitored, and you are not making good progress a repeat caesarean will be advised. You will be involved throughout your labour with the planning of you care.

Take home message

When contemplating future pregnancy & birthing choices it is important to be fully informed and weigh up the pro and cons of all of your options and discuss this with you doctor.

 It is also important to ensure that if you are contemplating VBAC that you have access to a hospital facility that is well equipped for emergency caesarean section.

Despite the mode of delivery whether it be vaginally or via caesarean section the most important factor is the safety of both you and your baby, and that you birthing experience is both rewarding and satisfying