VBAC: the facts, the issues

Gina Lowdon and Debbie Chippington Derrick have gathered together research and experience to support the case for vaginal birth after caesarean.

It is well acknowledged that the caesarean section rate in the UK is too high and still rising. There is much debate on the reasons for this and how the trend may be reversed. VBAC (pronounced vee-back) or vaginal birth after caesarean, is still not seen as the norm, especially if a mother has had more than one caesarean. Mothers approach VBAC in a variety of ways and there is a lot to learn from their experiences. There appears to be little room for improvement in outcome when the caesarean rate rises above 7%.[1] Since our caesarean section rate reached 15.3% in 1993,[2] this means that over half the caesarean operations that take place today could be avoided without harm to mothers or babies. So why are so many babies caesarean-born?

Cascade of intervention

The clues to some of the answers lie in the events which lead up to the point where a caesarean is deemed necessary. Caesarean mothers often recount a long list of interventions, known as a 'cascade of intervention', where the natural flow of labour is lost and a caesarean becomes inevitable. The first step on such a path may sometimes come when a mother goes 'overdue', as most hospitals have a policy of induction at around 10-14 days past the due date, although some research has shown that average duration of pregnancy for white first-time mothers may be over 41 weeks.[3] Although many women welcome the end of what may be an uncomfortable stage of pregnancy, others can feel under pressure to conform to accepted policy. Although substantial numbers of women do go on to have straightforward vaginal deliveries following induction, women who would naturally tend to have longer pregnancies may not be physiologically ready, and those who feel unhappy about the decision to induce may not be pyschologically prepared to labour, predisposing the induction to 'fail'.

Failure to progress

Mothers who feel frightened, unsure, out of control and unsupported, or who find it difficult to cope with the 'medical model' of birth, are all more likely to 'fail to progress' in labour or to have babies who become distressed. These are the two most common reasons for the performance of emergency caesarean sections. Some mothers need continuity of care from a known and trusted professional, while others cannot labour effectively in a hospital environment, needing the sanctity of their own home. The majority of breech-presenting babies are now delivered by caesarean section. Although there is still disagreement as to the benefits of elective caesareans for the healthy, term breech baby, many practitioners today lack the skills necessary for vaginal breech delivery,[4,5] After two or more caesareans, it is common policy for mothers to be automatically scheduled for an elective (planned) caesarean, since it is widely believed that the risks of caesarean scar rupture increase with the number of caesarean operations. Lack of evidence supporting this theory, however, has led some researchers and obstetricians to question the basis for this accepted practice.[6,7] There also seems to be a general attitude that a mother who has already had two or more caesareans surely must require another for a subsequent birth, although this is unlikely to be the case.[8]

Evidence of safety

There is evidence to support the safety and desirability of VBAC. Two reports using computer decision analysis to compare VBAC against elective repeat caesareans bath came out very strongly in favour of VBAC.[9] The highly respected Guide to Effective Care in Pregnancy and Childbirth supports VBAC and states that the likelihood of vaginal birth is not significantly altered by the indication for the first caesarean (including 'cephalopelvic disproportion' and 'failure to progress'), nor by a history of more that one previous caesarean.[10]

Avoiding further caesareans

Caesarean mothers who wish to avoid further operative deliveries can provide us with many of the clues to the ways caesarean section rates can be reduced. These mothers are generally more focused and often have a much clearer idea than first-time mothers of their needs. In order to avoid further surgery, caesarean mothers seem to effect change in one of three ways:


  1. Enkin, M, Keirse. M, Renfrew, M and Neilson, J 1995: Effective Core in Pregnancy and Childbirth. 2nd ed. p318.
  2. Francome, C 1994: Caesarean Birth in Britain (Supplement). p1.
  3. Van der Kooy, B 1994: Calculating expected date of delivery - its accuracy and relevance. Midwifery Matters, no. 60, p3.
  4. Enkin. M. Keirse, M, Renfrew, M and Neilson, J 1995: Effective Care in Pregnancy and Childbirth, 2nd ed. pp142-143.
  5. Cox. J P 1988: Delivery alternatives in the term breech pregnancy. ICEA Review, vol. 12, no. 4.
  6. Enkin, M, Keirse, N, Renfrew, N and Neilson. J 1995: Effective Care in Pregnancy and Childbirth. 2nd ed. p288.
  7. Roberts, LJ 1991: Elective section after two sections - where's the evidence? British journal of Obstetrics and Gynaecology, vol. 98, pp 1199-1202.
  8. Enkin, N. Keirse, M, Renfrew, M and Neilson, J 1995: Effective Care in Pregnancy and Childbirth, 2nd ed. p293.
  9. Flamm, B L 1992: Birth After Caesarean, the Medical Facts. P51.
  10. Enkin, M. Keirse, N, Renfrew, N and Neilson, J 1995: Effective Care in Pregnancy and Childbirth, 2nd ed. p293.

Gina Lowdon and Debbie Chippington Derrick

First published in NEW GENERATION the journal of the NCT December 1996

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