Vaginal birth after caesarean (VBAC): does it still have a place in 2012 and beyond?

Women who have undergone one birth by caesarean section often have the option of vaginal birth after caesarean (VBAC) or planned caesarean section (CS) for their next delivery.

It has been well recognised for a long time that there is a small risk associated with VBAC (about 3:1,000) of the scar on the uterus separating or rupturing during labour and that on occasions this can pose a serious (life threatening) risk to the baby and a risk of serious bleeding to the mother.

There are many factors which will influence the decision to attempt a VBAC or to choose planned CS, factors relating to the circumstances of the previous caesarean, issues in the current pregnancy as well as personal preference, medical support in the unit where delivery is occurring etc. These are all important things and need to be discussed on an individual basis.

A recently published Australian study has added some further useful information to this topic. The study’s lead author is Caroline Crowther from Adelaide University. The study examined the pregnancy outcomes of over 2,000 women who had a history of one previous caesarean section and who were considered suitable for a VBAC. About half the women attempted VBAC and the remaining half underwent planned CS. These two groups were then compared. Of the women who attempted VBAC about half were successful in terms of achieving a vaginal birth, the remainder underwent emergency CS during labour. The overall pregnancy outcomes were excellent in both groups with a very high proportion of mothers and babies safely delivered. However there were 2 significant areas of difference between the groups.

  • Firstly, the “attempting VBAC” group had a higher rate of babies dying or suffering serious complications around the time of birth when compared with the “planned CS” group (2.4% vs 0.9%).
  • Secondly, the “attempting VBAC” group had a higher rate of maternal haemorrhage and higher rate of blood transfusion when compared with the “planned CS” group.

This study was conducted across a number of hospitals in Australia and was carried out by a very reputable research group, the findings are likely to be valid and reliable. So whilst these differences are small they are significant.

Does this mean that VBAC no longer has a place in “modern” obstetrics? Should we go back to the old maxim “Once a caesarean, always a caesarean”? I don’t think so. There very likely will always be a place for VBAC in current childbirth practice. However women and their carers need to be mindful of the small increased risks associated with attempting VBAC and take this into consideration when making decisions about the most appropriate and safest mode of delivery for both mother and baby.

I think it is important that decisions around VBAC be tailored to the individual circumstances but there are a few general points I would like to make

  • there should be a minimum of 18 months between the initial caesarean and the VBAC attempt
  • VBAC success rates are higher if the baby is not too large (eg estimated < 4kg)
  • it is ideal to avoid induction of labour in VBAC, much better for labour to begin naturally
  • better and safer to do a planned CS rather than a “difficult” VBAC induction
  • epidural is a perfectly safe pain relief option in VBAC (if desired)
  • continuous monitoring of the baby’s heartbeat in labour is an important part of the safe care of VBAC

As with all these types of issues general advice, information and guidelines are all very helpful but are no substitute for personalised and individualised care.

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