Safety of a vaginal birth after a caesarean (VBAC)

By Barbara Hanrahan – Nursing sister and midwife, masters in midwifery, SA certified perinatal course developer

Do you know you can have a vaginal birth after a previous caesarean birth? (VBAC)?

Research has proven that this is possible – with about an 84% to 91,3% rate for successful VBAC. In Johannesburg, in the private sector, there are obstetricians who will assist a woman with a VBAC – recognizing that the best way to approach this is with a private midwife – as she provides one on one labour support and monitoring during labour. This vigilance reduces the risk of complications and the very low risk of a possible uterine rupture. An added value of one-on-one care means that if a caesarean is required, the midwife and team that the woman knows, go to theatre with her. Thus reducing stress associated with an unscheduled repeat caesarean birth.

The impact of a negative birth experience and the affects impact a woman in the long term. For some women, a caesarean birth may leave them dissatisfied with their birth experience. This can affect whether the woman chooses to breastfeed her baby, the length that she breastfeeds for, her mothering ability in the first year, the risk of postpartum depression and increases the risk of post-traumatic stress disorder.

The first blow to a woman’s confidence in her body is usually quite early in the pregnancy, when her doctor initiates the subject of a caesarean section. So doubt arises early in the pregnancy and gets “fed” by the horror stories women insist on regaling to any pregnant women they see. Women do have an altered body image in pregnancy as their pregnancy develops and this is the time to affirm that her body is strong and capable (the very fact that she is growing a foetus with no technical help!)

“Rupture of the uterus” is the number 1 reason for health practitioners to prefer a repeat caesarean. This is when the previous caesarean scar’s internal structure starts to separate. A true rupture of the uterus is rare when there is sufficient monitoring in labour. Rupture of the uterus is a potential problem with hyper-stimulated contractions, prolonged labour and CPD (cephalo-pelvic disproportion). All of which have early warning signs.

Criteria for doing a VBAC include the baby’s head being in the correct position ie head first, transverse scar in the lower segment of the uterus and an average foetal weight. These criteria do not rule out incidental problems such as foetal distress – which can happen in any labour. With vigilant monitoring – not continuous foetal monitoring, foetal distress can be detected early enough to investigate the nature of the distress and the options for care at that point.

Women deserve and need a full account of the benefits and risks of a VBAC or repeat caesarean. Yes any caesarean has inherent risks – which women are often not told about all the risks – or it is put in a way that caesarean minimizes the risks and women feel “it’s no big deal”. The terms used to explain the situation can be “massaged” to draw the woman into the decision the doctor wants her to agree with. Equally this surreptitious enhancing of the facts can be done by a practitioner who readily supports VBAC and wants to lead the woman to the decision to go for a VBAC.

On examining the research evidence, factors which influence a VBAC can be from events around the first caesarean, some relating to the woman’s previous birth experience and some around learning from a previous caesarean.

Some interesting facts

  • If a woman has given birth vaginally prior to caesarean then the risk of rupture of the uterus is significantly lower.
  • Single layer suturing of the caesarean wound is infinitely riskier in a future VBAC vs double layer repair. Women need to know the “real” reason for a caesarean and how that caesarean has been stitched – they will have to ask. Review your medical file before you leave the maternity facility.
  • Postpartum fever has been associated with an increased risk of uterine rupture in the next labour. Interpreting this fever needs to consider whether it was connected to epidural or spinal anesthesia or the use of Misoprostol to reduce post caesarean bleeding. Both of these instances are known to raise maternal temperature.
  • Previous caesarean done for non-repeatable reasons eg breech position offers more chance of a successful VBAC. Poor progress in labour or CPD offers a higher risk of a repeat caesarean.
  • Women in whom there was a 24 month period before falling pregnant again had the smallest risk of rupture of the uterus. This suggests that the scar in the uterus needs two years to heal to its optimal strength.
  • The risk of rupture of the uterus increases after each caesarean. Previous research quoted an incidence of 0,6% after 1 previous caesarean, increasing to 1,7% after two or more caesareans.
  • Results of vaginal delivery following more than one previous lower segment caesarean section are no different to those following one previous caesarean section
  • There is a direct correlation between perinatal mortality and induction of labour in women who have had a previous caesarean.
  • Women who had a successful VBAC were less likely to get a raised temperature vs women who had an elective caesarean.
  • Women who had a successful VBAC are markedly less likely to receive a blood transfusion than women who have had an elective caesarean.
  • Babies born by elective caesarean are significantly more likely to encounter breathing difficulties. Babies born by emergency caesarean after attempted VBAC had a higher rate of postpartum infections. Babies born by successful VBAC have good neonatal outcomes. Thus a successful VBAC is of benefit to the baby and an unsuccessful VBAC is no worse than an elective repeat caesarean birth.
  • A woman’s birth experiences will contribute to the interest in a VBAC. Women who have experienced a “traumatic caesarean” for foetal distress or failure to progress in labour may be more likely to choose an elective repeat caesarean vs a VBAC. Debriefing the birth irrespective of the mode of birth, helps a woman focus her thoughts on another childbirth experience in the future – so that she goes away from the recent birth experience with a more global perception of a successful birth strategy for the next pregnancy. And knows all the important facts of this birth – so that the woman can process them and make sense of her birth experience.

VBAC is a personal choice – The Guidelines to Maternity Care in South Africa allows for a woman with a previous caesarean to choose an elective repeat caesarean. But the old adage “once a Caesar – always a Caesar” cannot be applied to all births following a previous caesarean. Especially in South Africa with its very high primary caesarean rate. Be encouraged to work thoughtfully through your birth options, including feeling secure with your caregiver if the “what if’s” happen and provide emotional support and debriefing for women who have experienced an unexpected birth outcome which the woman may view as traumatic.

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