I’ll have to admit this – the last vaginal breech birth I assisted was around three years ago. I was on-call for a tertiary hospital and received a telephone call at 2am on a Monday morning.
The fourth-year trainee on night duty explained that he had assessed a woman in her first pregnancy at 38 weeks who had presented in labour, at around 5 cm dilatation, with a breech presentation. He sought my permission to perform a caesarean section.
I remember grunting my assent before falling back to sleep, only to have the telephone ring again about 20 minutes later.
‘I’m in theatre, just about to catheterise. I can see buttocks at the introitus. Should I go ahead with the caesar?’
‘How many vaginal breeches have you delivered?’ was my response.
After a moment’s silence, he broke it to me. ‘Well, um, I’ve seen one.’
‘Do nothing, I’ll see you soon.’
Most of us would expect this scenario to have a happy ending, as it did, with a straightforward assisted vaginal breech birth.
I trained in a unit where there was considerable enthusiasm for vaginal breech birth. It was in fact one of the recruitment centres for the study, Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial, now commonly referred to as the Term Breech Trial (TBT).1 As a second-year trainee, when the TBT was ultimately published, the resulting drop in enthusiasm for vaginal breech delivery was obvious, although most of the senior consultants were still prepared to supervise vaginal breech births. From a trainee perspective, though, I was concerned that the only vaginal breeches I’d be managing would be with a doll and pelvis in the birth suite tearoom! Ultimately, I gained enough personal experience in vaginal breech birth to practise independently, although it has obviously been a while now. Pilots need to re-certify on a regular basis, in particular after a prolonged leave of absence, but what about obstetricians?
Although about 40 per cent of singleton fetuses present by the breech at 20 weeks, this figure falls to about 25 per cent by 32 weeks, and thence to a prevalence of around three to four per cent by term. Breech presentation is associated with nulliparity, multiple pregnancy, breech presentation in a previous pregnancy, uterine anatomical anomalies, placenta praevia, poly- or oligohydramnios and fetal anomaly.2 Ford reports breech presentation at term in 4.2 per cent of first pregnancy deliveries, 2.2 per cent of second pregnancies, and 1.9 per cent of third pregnancies, with recurrence of breech presentation of 9.9 per cent after one consecutive and 27.5 per cent after two consecutive breech deliveries.
The literature pertaining to breech birth is dominated by the TBT, published ten years ago. That large, multicentre randomised controlled trial was designed to compare a policy of planned caesarean section with a policy of planned vaginal birth for selected breech presentation pregnancies. The TBT involved 121 centres in 26 countries, randomising 2088 eligible women to planned caesarean section or vaginal breech birth. The primary outcome measures used to plan the TBT were perinatal or neonatal mortality at less than 28 days of age (although excluding lethal congenital anomalies), or one of a number of measures of serious neonatal morbidity. Maternal mortality or serious maternal morbidity were the secondary outcome measures. There have been a number of related papers published, dealing with longer term follow-up data and subanalysis of the original trial data.
For women randomised to the planned caesarean section arm, 90.4 per cent were delivered by caesarean section, while of those randomised to the planned vaginal birth arm, 56.7 per cent were delivered vaginally.
Perinatal mortality, neonatal mortality, or serious neonatal morbidity were all significantly lower in the planned caesarean section arm than the planned vaginal birth arm (1.6% vs 5.0%; relative risk 0.33 [95% CI 0.19-0.56]; p<0.0001). There were no differences in maternal mortality or serious maternal morbidity in the two arms (3.9% vs 3.2%; relative risk 1.24 [0.79-1.95]; p=0.35).
A reduction in the number of vaginal breech births undertaken in Australia and elsewhere in the world occurred almost immediately following publication of the TBT, although this seemed to accelerate a trend that had already been noted. For example, the change in the Netherlands was most impressive, with an increase in the caesarean section rate for breech presentation from 50 per cent to 80 per cent within two months of publication of the TBT.3 The horse had already bolted in the United States, with reports indicating that in 1999, 84.5 per cent of fetuses diagnosed with ‘breech/malpresentation’ were delivered by caesarean section, with the American College of Obstetrics and Gynecology (ACOG) subsequently recommending planned caesarean delivery rather than planned vaginal delivery for term singleton breech presentations in 2001, in response to publication of the TBT.4
Sullivan and colleagues studied caesarean section rates where breech presentation was the sole or main indication in Australia between 1991 and 2005.5 They reported a change in method of birth for term breech singletons over the study period. In 1991, vaginal delivery constituted 23.1 per cent of all deliveries with a breech presentation at term, with the remainder obviously by caesarean section, of which 55.6 per cent occurred pre-labour, the remaining 21.2 per cent reported as intrapartum. By 2005, only 3.7 per cent of fetuses in breech presentation at term were delivered vaginally. Although the trend was for abandonment of vaginal breech delivery over the whole study period, the authors noted a ‘small but immediate’ rise in the rate of caesarean section for breech following publication of the TBT.
Few large studies have generated as much comment as the TBT. The literature is replete with questions pertaining to selection criteria used in the study, conduct of labour in the planned vaginal birth arm, and apparent inconsistencies in intrapartum care in the TBT. For example, Kotaska6 has highlighted the potential limitations of applying a multicentre randomised controlled trial to complex phenomena such as a vaginal breech birth.
If the method of birth for a fetus in breech presentation at term remains contentious, then it seems logical to pursue strategies to reduce the prevalence of breech presentation. External cephalic version (ECV) at or very near term has been shown to be an effective way of reducing the prevalence of breech presentation, and this has been confirmed by meta-analysis.7 Pooled data provide reassurance that ECV is safe and effective, whereas postural techniques8 and moxibustion9 have not been shown to be similarly useful.
Ten years on from the TBT, various international guidelines have included recognition that for certain populations, vaginal breech birth may be offered. The Royal College of Obstetricians and Gynaecologists (RCOG) guidelines10 highlight the findings of the TBT and list a set of ‘unfavourable’ clinical features that confer increased risk to the woman and her baby should vaginal breech birth be undertaken. These include:
- Other, separate contraindications to vaginal birth (for example, placenta praevia or a pre-existing compromised fetal condition).
- Clinically inadequate pelvis.
- Footling or kneeling breech presentation.
- A large baby (defined as a birthweight predicted to be larger than 3800 g).
- A growth-restricted baby (defined as smaller than 2000 g).
- Hyperextended fetal neck in labour (diagnosed with ultrasound, or x-ray where ultrasound is not available).
- Lack of the presence of a clinician trained in vaginal breech delivery.
- Previous caesarean section.
The guideline further describes conditions for undertaking labour and intrapartum actions that constitute ‘appropriate care’.
Acknowledging that caesarean section will be the preferred mode of delivery for most obstetricians, in 2006 ACOG11 revised their 2001 guidelines, by stating that: ‘…planned vaginal delivery of a term singleton breech fetus may be reasonable under hospital-specific protocol guidelines for both eligibility and labour management’.
RANZCOG12 also acknowledges that, although most women with breech presentation at term will birth by caesarean section, management should be ‘individualised’. Factors that may reduce fetal risk from planned vaginal breech birth include:
- Continuous fetal heart monitoring in antenatal labour.
- Immediate availability of caesarean facilities.
- Availability of a suitably experienced obstetrician.
- Presumed ‘favourable fetal circumstances’. That is, the fetus is small or of average size, and no placental insufficiency is suspected. Also, the fetus is in a frank breech position, of appropriate gestational age and with documented head flexion.
- ’Favourable maternal circumstances.’ That is, an ‘adequate pelvis’, anticipated maternal cooperation with pushing, and preferably multiparity.
Rising caesarean section rates are of special interest to many public-health organisations. For example, New South Wales Health recently released a policy document, Maternity – Towards Normal Birth in New South Wales13, that recommends aiming for 100 per cent access to ECV by 2015, and compelling level five and six maternity services to consider accessing vaginal breech birth services.
A feature common to many international guidelines is the availability of a suitably trained obstetrician to be involved with a vaginal breech birth. I was fortunate to have the training of my seniors, but as a Fellow of five years standing, I have not had the opportunity to teach my trainees. The tearoom doll and pelvis will need to be formalised into a clinical skills station, in much the same way that we simulate basic surgical skills.
A survey of Australian trainees performed in 2006 reported that only half of final-year trainees felt confident with vaginal breech delivery. Furthermore, only 11 per cent of senior trainees reported an intention to offer planned vaginal breech delivery at term as a specialist. It would be interesting to repeat this study after another full training cycle.
Ten years on from the TBT there seems to be renewed interest, both in Australia and New Zealand, and indeed internationally, in offering vaginal breech births to appropriately selected and counselled women. From my own perspective, I hope it’s a colleague and not a lawyer who asks me, ‘When was the last time you assisted a vaginal breech birth, doctor?’