Commentary: The Freezing Aftermath of a Hot Randomized Controlled Trial
Address correspondence to Marc J. N. C. Keirse, MD, DPhil, DPH, FRCOG, FRANZCOG, Department of Obstetrics, Gynaecology and Reproductive Medicine, Flinders University, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
One swallow does not make a summer. However, as the contributions of Dr. Lawson and Dr. Kotaska indicate, one randomized controlled trial can make a freezing winter.
It is easy to shrug off these two case reports. They are only anecdotes, low-level evidence, and they occurred at the bottom and top ends of the globe. But, how many similar events have happened unreported elsewhere? Fortunately, not all have had such disastrous endings. In another Australian hospital, a woman was admitted at 34 weeks of gestation with full dilatation and a breech presentation nearly on view. Considering the “evidence” from the term breech trial (1), it was assumed that what is best for term babies must be even better for preterm babies. When the abdomen was opened there appeared to be no one to benefit from that logical reasoning. The beneficiary was discovered comfortably lying between its mother’s legs underneath the sheets, testifying to the fact that cesarean section is the optimal mode of delivery for breech babies.
What went wrong in each of these situations? There is nothing wrong with the reasoning that a breech presentation is more hazardous for a preterm baby than for a term baby. The cardiotocogram presented by Dr. Lawson is about as normal as one can find in the second stage of labor for any baby, whether breech or cephalic. Home birth is a well-established recipe for disaster for a baby in breech presentation (2,3) and contrary to any sensible guidelines that have ever been developed (4–6). Yet, having no choice other than cesarean section or an unattended home birth is akin to having a choice only between the devil and the deep blue sea. So, who is to blame for such outcomes?
Clearly, the blame must rest fairly and squarely with what was heralded as a new paradigm (7), “evidence-based medicine” or with our inability to come to grips with it. A new paradigm essentially means a new scientific order in which there is no place anymore for the concepts of old. In the new evidence-based paradigm anything randomized became the gospel and anything else became either low evidence or lack of evidence. Obstetrics, perhaps even more than any other discipline, fell victim to this new paradigm determined as it was to get rid of the slur that had hounded the specialty before.
Painting a Wooden Spoon
In 1979, Archie Cochrane had awarded obstetrics the wooden spoon for introducing a major change in childbirth practice (from home to hospital) without subjecting it to a randomized controlled trial (8). It took 10 years for that slur to be withdrawn (9), but the effect was dramatic. All childbirth practices, irrespective of whether they were sensible or not, needed to be either discarded or reestablished within the new paradigm. The term breech trial (1) was a prominent embodiment of the new approach. In the trial coordinators’ own words, it was meant “to give the option of vaginal breech birth its best, and perhaps last, chance to be proven a reasonable method of delivery” (1). Hence, the complex issue of how to conduct and supervise labor and birth for a baby in breech presentation was reduced and simplified to an apparently straightforward randomizable question of whether to “pull it out or cut it out.”
The fallacy of that reasoning has been pointed out previously (10–12). Trial data, published later (13), bear their own testimony to that fallacy, although this is not what its authors concluded. The main fear at the birth of a breech baby is birth trauma, but this outcome can occur just as well, and for the mother too as reported by Dr. Lawson, when extracting a baby through a uterine incision. Of 13 infants who suffered birth trauma in the term breech trial, 7 had been planned for a vaginal birth and 6 for cesarean section with 1 in each group not born as planned (13). The six injuries at cesarean section were also substantially more serious than the seven at vaginal birth (13). The same data (13) also testify to the overwhelming importance of the conduct of labor over and above the simple question of route of delivery. When disregarding data for countries with perinatal mortality rates above 20 per 1,000 births and concentrating on births that occurred vaginally, the conduct of labor accounted for twice as many adverse outcomes as the birth itself, despite the fact that 55 percent of women were already in labor before being randomized (13). More than 70 percent of the adverse perinatal outcomes attributed to labor or birth also occurred in labors that were induced or augmented (13). No deaths and only seven of the aggregate adverse outcomes attributed to labor or birth occurred when labor had been spontaneous without induction or augmentation, and in only one of these seven was an obstetrician present at the time of birth, let alone during labor (13).
What Went Wrong with the Term Breech Evidence?
In the term breech trial, very little, if anything, went wrong with the trial itself. As the then editor of the BJOG remarked, it was impeccable in methodological design, but questionable in clinical design (14). Trial methodology came to govern clinical wisdom and common sense. Virtually no institutions with good breech birth outcomes reach vaginal birth rates as high as those in the term breech trial (57%), where participating centers with low vaginal birth rates were told to either increase their rate or withdraw from (sponsored) participation (11). To what extent boundaries of clinical safety were stretched (11) for the sake of statistical power will remain unanswered. Composite outcomes also reflected the need for statistical power rather than what matters for mothers and babies in the long run. So did the selection of participants, resulting in a mortality rate of 10 percent among low-birthweight babies born vaginally (15), and the wide margins set for the allegedly safe conduct of vaginal breech births in terms of labor progress and attendants during labor and birth.
Randomized controlled trials may be the optimal way to resolve uncertainty as to what is the better among alternatives that seem reasonably equivalent. If not reasonably equivalent, a practitioner’s duty of care would preclude anyone being randomized to the inferior of the available alternatives. However, what reasonable equivalence can there be between a planned cesarean section in a fully equipped operating theater and a vaginal breech birth under conditions permitted within the term breech trial? The latter included poor surveillance during labor, intervals up to 18 hours between active labor and full dilatation, up to 3 hours thereafter, with active pushing for up to 1.5 hours, and absence of a qualified obstetrician at the time of birth, let alone during labor, in more than 20 percent of cases. With such antiquated criteria for the safe conduct of vaginal breech birth, a fair comparison would have been with cesarean sections as they were done a century ago or, alternatively, with the surgery performed on someone’s kitchen table.
It is relatively easy to be wise in retrospect, though. It is obvious that those conducting and participating in the trial genuinely felt that they were contributing to resolve an important question that had been a hot issue for some time. Despite the good intentions, they fell into the trap that had governed obstetrics for a very long time, namely, that the most important issue is how to get the baby out of the mother. So, the new paradigm of evidence-based practice got mixed up with an old forgotten paradigm that had been epitomized by oodles of forceps designs, now mostly stacked away in museums. Before being too critical of their efforts, it may be worth considering that the issue of where to get the baby out of the mother, at home or in hospital, is still suffering from a similar phenomenon. Where the cord is cut seems to be more important than the circumstances preceding and surrounding it, let alone adequate selection criteria (16).
From So-named Evidence to Standard of Care
When the term breech trial was published (1), accompanied by an editorial unequivocally endorsing its conclusion that all breech babies should be delivered by cesarean section (17), several professional bodies unthinkingly endorsed the new dogma. As Dr. Kotaska points out, several have had second thoughts since, but not from a careful analysis of what could have been derived from the original trial report. Not in time, either, to undo its effect on obstetric skill and its far-reaching consequences.
A fundamental issue is that probably no study with selection and management criteria such as those applied in the term breech trial would have seen the light of day in a prestigious journal if it had not been randomized. Of course, nothing is wrong with advocating or promoting randomized trials. There is a great deal wrong, though, with the perception that evidence, to be evidence, needs to be randomized evidence. There is also a great deal wrong with the belief that only evidence is an e-word that deserves to be written with a capital “E,” whereas other e-words, such as education, experience, expertise, and even excellence, are merely ignominious.