For show notes including all the results for this trial: http://www.ebmpodcast.com/breech
The Term Breech Trial is one of the most important clinical trials in the history of obstetrics and has changed the way we manage breech presentation across the world.
The term breech trial was as randomised controlled trial comparing planned caesarian section to planned vaginal delivery for management of breech presentation at term.
2088 pregnant women, who were presenting in a breech presentation at 37 weeks or more, were randomised to one of two groups: planned vaginal delivery OR planned caesarian section. Women were recruited from 26 different countries using 121 clinical centres.
The women could either have frank breech or complete breech, but they were excluded if they had a footling presentation. Women were also excluded if they were having very large babies – They defined really big as an estimated weight of 4kg or more which is 8.8 pounds (for the Americans)
Allocation was concealed and the plan would be that if they were randomised to the C-section group, they would schedule it in at anytime from 38 weeks onwards. On the day of the C-section, they would make sure the baby was still in breech, and if it had managed to move to be in cephalic presentation they would then just plan a normal vaginal delivery. About 40% of the mums where randomised at the time of labour, and so they would have been pretty quickly rushed off to get their Caesarian section after being randomised to that group. If they were randomised to the planned vaginal delivery group, they would just wait for them to labour spontaneously, unless for whatever reason they needed induction of labour and they had a whole protocol on how induction of labour was to be managed.
The primary outcome was the death of the baby either during labour or in the first 28 days of life, or like really bad things happening to the baby. And there was a heap of these: birth trauma, which included subdural haematoma, intracerebral haemorrhage, spinal-cord injury, basal skull fracture and peripheral-nerve injury or clinically significant genital injury; seizures occurring at less than 24 h of age or requiring two or more drugs to control them; Apgar score of less than 4 at 5 min; cord-blood base deficit of at least 15; hypotonia for a least 2 h; stupor, decreased response to pain, or coma; intubation and ventilation for at least 24 h; tube feeding for 4 days or more; or admission to the neonatal intensive care unit for longer than 4 days.
Of those assigned to C-section – 90% were actually delivered by C-section. The 10% who were delivered vaginally, did so either because they managed to turn to cephalic presentation, or they had progressed too quickly in labour that it was too late for C-section, or because the mother changed her mind last minute and decided against a C-section.
Of those assigned to the planned vaginal birth – only 56% ended up delivering vaginally. The rest were delivered via C-section and the most common reason being that they just weren’t progressing in labour or the baby was too big for the pelvis.
So what were the results? Well that composite primary outcome – with all the bad stuff that can happen to a new born baby, coupled with some less bad stuff – went from 5% in the planned vaginal delivery group to 1.6% in the C-section group. So there was a 3.4% decrease in what they called serious neonatal morbidity or neonatal/perinatal mortality with planned C-section over planned vaginal delivery. The number needed to treat was 30, which means for every 30 breech babies we deliver via planned C-section instead of planned vaginal delivery, we will prevent 1 bad thing happening to the baby.
So let’s look at the breakdown of the components of this primary outcome:
Starting with perinatal or neonatal death – this went from 1.3% with planned vaginal delivery, to 0.3% with planned C-section, so a 1% decrease in baby death with planned C-section
Birth trauma went from 1.4% to 0.6% with planned C-Section and this was mainly because of decreased bone fractures and brachial plexus injuries
Hypotonia which lasted greater than 2 hours went from 1.8% to 0.2%
There was a decrease in Low Apgar score at 5 minutes, it went from 0.9% to 0.1% with planned C-section
Rates of intubation and ventilation also decrease – from 1.3% to 0.3%
And neonatal ICU admission decreased from 3% to 1.5%
In terms of maternal outcomes – there was really no difference here. No difference in postpartum bleeding, mortality, genital tract injury, wound issues or infection. Having said that…they didn’t look at pain and return to normal function which I think we know would have been better in the planned vaginal delivery group.
Interestingly, they re-analysed the data, to see if there was a difference in baby outcomes depending on how well trained the obstetrician was in doing vaginal breech deliveries. And it did seem to make a difference: instead of that 5% risk of the primary outcome with planned vaginal delivery – If the only looked at obstetricians was super trained – with more than 20 years experience in delivering breech babies, this primary outcome went down to 3.2%. Which is still greater than C-section which if you remember was 1.6% but still, better than the vaginal breech delivery average.
This study quickly had a tremendous impact on practice almost immediately after publication:
For breech delivery in the Netherlands for example, the caesarian section rate went from 50% to 80% within 2 months of this study being published.
The American College of Obstetrics and Gynaecology changed their guidelines within a few months from the publication of this study to now recommend a planned caesarian section for all term singleton breech presentations.
In Australia, by 2005, only 3.7% of babies in breech presentation were delivered vaginally. And the number of obstetricians confident In performing a vaginal breech delivery is diminishing across the world.
In 2006 a survey was done on Australian obstetrics and gynaecology trainee’s who were in their final year of training, and only 11% of them said they would OFFER a vaginal delivery to their women in breech. I imagine this would me much less if done today.
The term breech trial researchers published another paper 2 years later where they followed up a selection of the original babies in the term breech trial to see if there was any difference in outcomes after a couple of years. Only 85 of the 121 birthing centres were pre-selected to be involved in this 2 year follow up. So out of the 2088 women in the actual term breech trial, 1159 were to be included in this 2 year follow up study. As the child reached 2 years of age, the investigators sent out questionares to these 1159 women about their Childs development. Questions about communication, gross motor skills, fine motor skills, problem-solving skills, and person-social skills. The plan was to see whether there was any difference in child death rates outside of the initial neonatal or perinatal period OR if thee was any neurodevelopment delay. They only managed to get data from 920 and they found no difference in death or neurodevelopemental delay between the planned C-section and the planned vaginal delivery from breech babies at 2 years follow up.
So whats the bottom line? Well I’ll leave the lead author of the study to answer that in a quote from a response to a commentary she published in the BMJ:
“for those women preferring a vaginal breech birth, they should be reassured that although planned caesarean section reduced the risk of perinatal or neonatal mortality or serious neonatal morbidity, compared to planned vaginal birth, in the Term Breech Trial, 95% of babies in the planned vaginal birth arm did well. Also, although our statistical power was limited, we did not find planned caesarean to be associated with better outcomes for the children at 2 years of age”
Term Breech Trial: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(00)02840-3/abstract
2 year follow up trial: https://www.ncbi.nlm.nih.gov/pubmed/15467565
music by Polyphonics song El Fuego