The Cochrane review on VBAC was updated a couple of days ago, although there was no change to the conclusions (below). The reviewers conclude that, while both planned cesarean section and planned VBAC for women with a prior caesarean birth are associated with benefits and harms, the lack of reliable evidence from randomised controlled trials means that current data (from other types of studies) must be interpreted with caution.
The main reason that these conclusions have not changed is because only a couple of very small trials have been undertaken in this area, and the main reason that only a couple of very small trials have been undertaken in this area (I would humbly argue, but perhaps you will disagree) is because there are very few women who would want the decision about whether they have a vaginal birth or a cesarean section to be decided by a throw of a random number generator.
Does this mean that we have to either throw our hands up in despair or start a search for those few altruistic women who really might not mind?
Not necessarily. These are the very challenges that should be spurring us on to think outside the box, consider different ways of knowing and explore further into the question of how we can generate useful evidence and knowledge that is respectful of women as both decision-makers and as participants in research.
When a woman has had a previous caesarean birth, there are two options for her care in a subsequent pregnancy: planned elective repeat caesarean or planned vaginal birth. While there are risks and benefits for both planned elective repeat caesarean birth and planned vaginal birth after caesarean (VBAC), current sources of information are limited to non-randomised cohort studies. Studies designed in this way have significant potential for bias and consequently conclusions based on these results are limited in their reliability and should be interpreted with caution.
To assess, using the best available evidence, the benefits and harms of a policy of planned elective repeat caesarean section with a policy of planned VBAC for women with a previous caesarean birth.
We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (30 September 2013) and reference lists of retrieved studies.
Randomised controlled trials with reported data that compared outcomes in mothers and babies who planned a repeat elective caesarean section with outcomes in women who planned a vaginal birth, where a previous birth had been by caesarean.
Data collection and analysis
Two review authors independently assessed trial quality and extracted data.
Two randomised trials involving 320 women and their infants were included. However, data for maternal and infant clinical outcomes were available from one trial with very low event rates, involving 22 women only.
For the primary outcomes maternal death or serious morbidity (one study; 22 women; risk ratio (RR) not estimable), and infant death or serious morbidity (one study; 22 women; RR not estimable), there were no statistically significant differences between planned caesarean birth and planned vaginal birth identified.
Planned elective repeat caesarean section and planned VBAC for women with a prior caesarean birth are both associated with benefits and harms. Evidence for these care practices is largely drawn from non-randomised studies, associated with potential bias. Any results and conclusions must therefore be interpreted with caution. Randomised controlled trials are required to provide the most reliable evidence regarding the benefits and harms of both planned elective repeat caesarean section and planned vaginal birth for women with a previous caesarean birth.
Dodd JM, Crowther CA, Huertas E, Guise JM, Horey D. Planned elective repeat caesarean section versus planned vaginal birth for women with a previous caesarean birth. Cochrane Database of Systematic Reviews 2013, Issue 12. Art. No.: CD004224. DOI: 10.1002/14651858.CD004224.pub3.