Although national guidelines have supported a resurgence of vaginal breech birth since the publication of the two-year follow-up to the Term Breech Trial1 and PREMODA study,2 uptake has been slow.3 Since 2009, the introduction of upright delivery positions has offered a successful avenue for reopening the dialogue.4 The largest published cohort study of upright vaginal breech birth (UVBB),5 on 435 planned vaginal breech births, demonstrated the success of a protocol focused on identifying dystocia at different stages of descent, introduced maneuvers to rectify problems, quantified their use, and presented the associated algorithm.6

We were encouraged to see more research on UVBB, this time by examining breech birth videos, published by Reitter et al,7 as all of us teaching breech have found it an excellent way to review nuances of new maneuvers. Although carefully conceived, executed, and interpreted epidemiologic research helps move medical understanding forward, Friedman's curve8, 9 and the Term Breech Trial10 exemplify how poor execution and interpretation of research can set us back for decades,11-15 creating unnecessary restraints on child bearers and practitioners. Unfortunately, the breech video study7 prompts comparable concerns related specifically to time constraints, which, given the low quality of evidence, can only be described as arbitrary.

The Reitter et al7 study was based on a convenience sample of 42 videos acquired by solicitation and chosen from the Internet; the stated aim was to “identify common features of upright vaginal breech births with good outcomes….” The common aspects of descent, dystocia, and rectifying maneuvers reported in the video study generally affirmed those that have already been identified and developed.5, 6, 16-22 The video authors’ quantification of complications and rectifying maneuvers would, of course, have been more reliably achieved through systematic data collection5 than through a convenience sample, yet this is not our biggest concern. More troubling is a new element introduced—timing. The authors report the following: “Most upright breech births occur within 3 minutes of the birth of the fetal pelvis…We introduce a physiological breech algorithm as an initial timekeeping framework for teaching, research, and practice.”7

Although the flow of events and maneuvers in the algorithm are not new, the introduction of three minutes as a potential time limit raises multiple concerns, not the least of which is that it is based on a small convenience sample, yet is presented as the norm. Proposing such a timekeeping framework for teaching risks creating another Friedman's curve, which has taken us over a half century to undo. It was not until 2018 that WHO began to recommend against the use of medical interventions to accelerate labor before 5 cm and abandoned the cervical dilatation rate threshold of 1 cm/hour during active first stage. Growing evidence demonstrates the latter is “inaccurate to identify women at risk of adverse birth outcomes.”11

Micromanaging birth by placing restrictions on timing undermines the focus on other decision-making strategies, drives overly prescriptive protocols, and escalates unwarranted alarm among practitioners already fearful about breech. Such fears have prompted unnecessary episiotomies and forceps.4 In addition, liability issues arise when rigid time limits become the focus and are enforced.

1 COHORT DATA SUGGEST A WIDER VARIATION OF TIMING NORMALCY

The algorithm in the video article recommends a three-minute limit from the birth of the umbilicus to the birth of the head. As this timing was not consistent with our clinical experience, or most breech practitioners with whom we consulted, we analyzed the systematic data (not a convenience sample) collected on a consecutive series of 47 planned UVBB at term managed by one of the authors (Daviss). Results differed considerably from the video study.

Figure 1 presents the time from the umbilicus to the birth of the head for the 36 breeches that delivered vaginally. Not unexpectedly, the primiparous women took longer to deliver on average, with 12 (50%) of the first-time birthers taking longer than three minutes. Indeed, half of all UVBB births took three or more minutes and would have risked intervention by forceps had the video study algorithm's timing been heeded. Yet, none of these babies required forceps, resulted in fetal demise, or had any long-term negative sequelae. These data are not unique. Recent analysis of a larger sample of systematically-collected UVBBs in another high-resource country has found similar preliminary results to ours, suggesting generalizability.

Timing from umbilicus to head out in 36 successful upright vaginal breech births from a series of 47 planned in Ottawa, Canada. *We included 3 VBACs with no prior vaginal births in the primip group

2 LIMITATIONS OF CONVENIENCE SAMPLES AND INFERENCES ABOUT TIMING

The term “convenience sampling” is a standard term in epidemiology to describe a nonprobabilistic sampling of the population. Convenience samples are by definition not appropriate for making inferences in science because they have not been collected systematically and thus cannot be considered representative. Sampling biases embedded in such data are not discernible, making generalizability inappropriate23—the very reason the Cochrane Collaboration does not consider convenience samples in systematic reviews.24 An example of a convenience sample would be to solicit from the Internet, whether or not people had reactions to their COVID-19 vaccination. Subsequently inferring this represented the rate and severity of vaccination reaction worldwide would be inappropriate and misleading. The videos are from a selected subset of women—those willing to have their births videoed and shared. Perhaps the ones that took longer or had complications were less likely to be shared, whereas those that were shared and included came predominantly from multiparous birthers. Unfortunately, there is no way to know.

In the video study paper, there is neither mention of the limitations of a convenience sample nor avoidance of generalizing in the conclusions. This small sample of breech videos has minimal or no medical information about the child bearers and babies and no explanation of how a “good outcome” was defined. Information about practitioners’ skill level, experience, standards, or protocols is also not included. Parity, which clearly affects length of labor (Figure 1), is unknown. There is no rationale presented for why the timing noted for a sample of “good outcomes” should translate into a prescribed time limitation; this could result in pathologizing normalcy.25 We contest the notion suggested by the authors that it is sufficient, in fact progressive, to avoid examining bad outcomes.7 Epidemiologists compare exposures for both desirable and undesirable outcomes to explore how exposures affect outcomes. If we want to understand the risks for developing lung cancer, we cannot just study those who do not have it.

3 USING OTHER CRITERIA FOR TEACHING AND PRACTICE

From 2008 to 2016, Daviss mapped out the cardinal movements and signs of dystocia on 53 planned vaginal breech births in Frankfurt that she attended and the consecutive planned vaginal breech births in Ottawa. These observations informed the development of the Frankfurt algorithm and protocol,6 which strategically avoid a focus on timing. Instead, they identify where descent tends to stall and provide maneuvers to resolve it, such as the failure of the baby to rotate once born past the umbilicus (adopted, but unreferenced by the video study). Although one wants to see progress, the time is purposefully not prescribed throughout the descent; care is framed by the observation of progress in following the cardinal movements. The status of the baby, how effective contractions are, and whether other maneuvers have already been needed are more critical. “Timing” is mentioned only with the delivery of the head, while carefully taking other parameters into account: “If the head does not look as though it is coming in the next contraction (in less than 2 minutes and less if the shoulders needed manual maneuvers), we consider using the Frank Nudge.”6 The Johann Wolfgang Goethe-Universität Klinikum in Frankfurt has made an intentional decision to continue to avoid timelines (personal conversation with Frank Louwen, February 2020), and they report continued good outcomes unfettered by such restrictions.

If the baby is not growth-restricted, but large and robust, the EFM (CTG) tracing is good, the cord is thick and full of blood, and the muscle tone is adequate, we are more reassured and understand from experience that our time is not as limited. However, when a baby is limp, dangling for more than a contraction or two with no effort to rotate or descend, with a thin empty cord, or the mother is exhausted, it is important to act. The primary focus is on the mother and baby rather than on the clock. Dysfunctional descent because of positional factors that cause the cord to compress can lead to acidosis, not duration per se. Decisions to act are made in conjunction with loss of fetal muscle tone and abnormal fetal heart tones. We are not convinced that a time limit alone should be created or enforced, and certainly not with a convenience sample or a study that includes only “good outcomes.” We have noted increased acidosis with some (but not all) of the longer time frames in our sample, but they have not led to long-term negative issues, in keeping with other evidence on acidosis.26

It is noteworthy that national guidelines rarely mention timing from the buttocks to the birth of the head. The Royal College of Obstetricians and Gynaecologists (RCOG) report on it, but couple it with observation of the condition of the baby and suggest action after three minutes (not before) from the umbilicus to the head.27 Dr Impey, the principal author, has also qualified that these timings were based on "expert opinion” using lithotomy position, and since they were published in 2017 and his own department adopted UVBB, the need for a longer time allowance has been observed without compromising outcomes. They now focus on following the upright cardinal movements, maneuvers, and protocols presented at the Oxford/Amsterdam/Sheffield conferences5, 6, 17-19, 21 (personal correspondence: Dr Impey July, 2020).

The video-study algorithm presents continous pushing as the norm once the buttocks are visible. Such unqualified prescription, not even quantified in the convenience sample analysis, is unjustified. Until more systematic research suggests otherwise, it appears better to follow the birther's lead, as research on cephalic births has recommended.28-30 Some have suggested that inexperienced practitioners require timelines. However, good teaching is the synthesis of salient points, not of timelines. Concentrating on time in the manner proposed by the video study may contribute to fear-induced rushing and decision making and become a distraction rather than a help. WHO generally cautions: “labour practices to initiate, accelerate, terminate, regulate or monitor the physiological process of labour…increase medicalization of childbirth…[and]undermine the woman's own capability to give birth.”11

4 MANEUVERS RE-EXAMINED

Forceps were never applied in our consecutive series or the 760 planned vaginal births from the three published studies of UVBB,5, 31, 32 where time limits were not a major focus. These data, along with the reality that inexperienced and experienced practitioners alike have caused damage with forceps in the breech,4 have brought the wisdom of the use of forceps in vaginal breech birth seriously into question.21

In parts of Europe and Canada, a critical piece of the protocol for speeding up vaginal breech birth in second stage is fundal pressure.6, 33 Although fundal pressure was used in 10 (24%) of the video births, it was excluded from the video-based algorithm without explanation.7 Creating time limits based on observed data where fundal pressure was used to enhance progress (and shorten delivery times) in a quarter of the births, and then ignoring it in the protocol, undermines the study's stated purpose.

Although we all enjoy publicly sharing the maneuvers for the common good, when presenting and publishing, proper attribution is scientific protocol to ensure safe dissemination of actual experience, evidence, and expertise. We concur with Dr Louwen's unease with Walker altering his maneuver, “the Frank Nudge,”5 renaming it “shoulder press,”7 and instructing to push on the subclavicular space rather than the shoulders.34 Practitioners have found this less effective, and it risks breaking the clavicles. It is also best employed as a steady push, not rocking.

Our first author (Daviss) discovered that, with upright positions, slender practitioner fingers can squeeze up past the parietal eminences to flex and rotate the aftercoming head of a breech. Developing and naming the maneuver the “Crowning Touch,” she presented it at seven breech conferences across Europe and the United Kingdom between 2013 and 2019, published instructions in her manual,21 and invited practitioners to try it and collaborate on an article.35 Observed once in the video study, the name was changed to “scoop and flex,” and a partial, unreferenced description is highlighted in their Figure 3. Banks once used one hand “near” the parietal eminences and a second hand on the cheekbones for flexion without rotation,36 but using two hands can cause serious lacerations.21 It would be wise for practitioners to go to the original sources for the full description, risks, and benefits of UVBB maneuvers.5, 6, 21, 35, 36

5 CONCLUSION

Protocols for safe and effective UVBB have been developed over a decade and a half through extensive clinical experience, introspection, and research by pioneers in the field. Evidence of effective care in UVBB without mandated time limits from buttocks to birth has been demonstrated in the three published cohort studies and in our data presented here. Developing time limits on breech descent inferred from a small convenience sample is epidemiologically inappropriate and worrisome. We have spent many decades freeing women from the iatrogenesis associated with Friedman's curve; it would be a mistake to fall into a similar clinical and legal straightjacket with UVBB. Unfortunately, “obstetric guidelines" quickly become entrenched, often used in a rigid manner never intended, risking pathologizing the normal, and driving litigation. Evidence and experience teach the limitations of time guidance. The focus should be on observation of the woman and the baby, not the clock.

Data cannot be made available because of privacy issues.

REFERENCES

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