Tag Archives: manoeuvres

Breech holiday, Frankfurt – from Olvindablog

Justifying to a seven-year-old Anubis why I’m going to Germany for my week off – and missing mothers’ day, helped crystallise objectives and motivation for this busman’s holiday* (*a form of recreation that involves doing the same thing that one does at work). “I’m going to see some babies be born bottom-first.” “Don’t you see that […]

via Breech holiday, Frankfurt — Olvindablog

Running start

frank breech

In Physiological Breech Birth training, we teach breech practice according to the consensus statements developed with experienced professionals in Principles of Physiological Breech Birth Practice (Walker, Scamell & Parker, 2016), including:

Care providers should not disturb women’s spontaneous movements in an otherwise normally progressing breech birth.

Mother-led positioning offers the greatest physiological advantages.

Sometimes maternal-led positioning is most conducive; sometimes judicious guidance is appropriate, especially to help resolve delay.

When facilitating a physiological breech birth, care providers proactively use maternal position (or change in position) to promote normal descent.

The pictures below demonstrate asymmetrical maternal movement in a normal breech birth, in which the mother assumes an upright, kneeling position, with freedom to move her torso up and down as she feels the need. Study of effective, spontaneous maternal movements during successful breech births teaches professionals about all normal birth. Instinctive maternal movement can be read as purposeful and meaningful, in light of radiological evidence of changes in pelvic diameters (Reitter et al, 2014) — rather than counter-productive and needing professional interruption or guidance.

In this picture series, the mother spontaneously lifts one of her legs into an asymmetrical, ‘running start’ position. If a professional detects a slight delay in descent, it may be appropriate to suggest a change of position by raising one leg or the other, as a first-line intervention, a ‘maternal manoeuvre,’ before hands-on intervention. Often a change in maternal position, or rhythmic maternal movement (“give it a wiggle”) will prompt spontaneous descent to resume.

This mother is raising and lowering her torso with the aid of her partner’s thighs.

Dropping her torso, arching her back and tucking her hips under.

Moving her hips back towards her heels.

Squatting back onto her heels. This creates maximum space in the pelvic outlet as the breech passes through the ischial spines. The mother will not ‘sit’ on her baby, preventing the birth, but will instead raise her hips again when she instinctively feels the urge to do so.

Rising up again, arching her back. Creating space in the pelvic inlet as the shoulders and head enter.

Squatting back down. Spontaneous movements constantly change pelvic diameters as the baby rotates through.

Torso and hips rise up as baby rumps. Thrusting hips forward has a protective effect on the perineum and opens the inlet to assist engagement of shoulders/head. ‘Fetal ejection reflex.’

Pressure as baby descends. The mother drops her torso down again.

Moving into Running Start. The baby has not completely rotated to sacrum-anterior. The mother spontaneously lifts the leg on the side of the fetal legs, creating further space to assist rotation of the torso and descent of the anterior arm.

Significant descent occurs with the next contraction.

Running start continues to make space for gravity to do it work.

Almost there.

Straight to his mother’s arms.

The physiological process of welcome continues without interruption.

Thank you to the mother, who gave permission for her birth photos to be used for educational purposes; and to her family and midwives. One of these images appeared in the article, Unexpected Breech: What can midwives do?, in The Practising Midwife.

The Birth of Leliana

Jessica with Leliana

Image: Jacqueline Sequoia, used with permission

From Atlanta, back to Asheville

Jessica’s baby remained persistently breech at term, and she was unable to find a provider in South Carolina to facilitate a vaginal breech birth. When she attempted to decline a CS and negotiate a vaginal birth, she was informed that if she came into the hospital in labour, she would be given general anaesthesia and her CS would be ‘a lot rougher.’ (Folks, the ACOG published something just for you: Committee Opinion No. 664: Refusal of Medically Recommended Treatment During Pregnancy.)

This was Jessica’s first baby, in a frank breech position (extended legs), with no additional complexities. Her sister, Family Practice Doctor Jacqueline Sequoia MD, heard about Dr David Hayes and Harvest Moon Women’s Health because they were hosting my physiological breech birth training. Jacqueline includes obstetrics as part of her practice and booked to attend the workshop with some colleagues. Jessica and her husband Brian met with Dr Hayes to consider their options, and once Jessica made her decision, found a rental apartment in Asheville on Craigslist.

Let’s contemplate that for a moment. In order to have support for a physiological birth, rather than the threat of a coerced CS, women are having to relocate to another state and rent temporary accommodation, because the baby is presenting breech.

When Dr Hayes and I arrived at Jessica and Brian’s apartment, Jessica’s labour appeared to be progressing well. As people entered her space, Jessica gradually moved into the tiny bathroom at the back of the apartment, reminding me of Tricia Anderson’s metaphor of cats in labour. I turned off the light. This labour had a journey, as all labours have. Throughout her journey, Jessica was surrounded by people who love her. At the end of it, Jessica beautifully and instinctively birthed her little girl, Leliana, who weighed 7lbs 8oz.

This video contains graphic images of a vaginal breech birth.

Being attuned to the general lack of training in physiological breech birth among health professionals, and the consequences for women and babies, Jessica and Brian were keen to share this video of Leliana’s birth to help others learn. If you would like to read more about the minimally invasive manoeuvres used at the end of this birth, you can read our blog on Shoulder Press and Gluteal Lift.

brian

Thank you, Jessica, Brian, Leliana, Dr Sequoia and Dr Hayes for sharing this video. The link to this blog post can be shared, but the video cannot be downloaded or reproduced without permission.

Shawn

https://twitter.com/jsequoia/status/736602696115879936

The midwives of Portsmouth and the aftercoming fetal head

Claire Reading sharing her skills

Claire Reading sharing her skills

This Tuesday, 1 March 2016, Breech Birth Network travelled to Portsmouth again. The guest speaker was lovely doctor Ms Arti Matah, who spoke about an obstetrician’s view of vaginal breech birth, and led a lively discussion around whether the breech team / care pathway model might work for Portsmouth. Watch this space! I am incredibly impressed with the commitment Portsmouth midwives have shown to developing sound breech skills to support women who choose to birth their breech babies actively.

The skill which captured the group’s imagination most was how to resolve a situation where the head is extended and impacted at the inlet of the pelvis. My research suggests that identification of optimal mechanisms is a core skill for practitioners attending breech births. Therefore our approach to teaching this skill is:

  1. Identification of optimal mechanism — The aftercoming fetal head normally rotates to the oblique/transverse diameter as it enters the pelvic brim, just like the cephalic-presentation head does when engaging.
  2. Identification of deviation from optimal mechanism — In this complication, the fetal head is pinned in the anterior-posterior diameter, with occiput anterior, over the maternal symphysis publis, and chin or brow on the sacral promontory. The bottom of the fetal chin is felt like a ‘bird beak,’ pointing towards the sacrum. The maxilla bones are difficult/impossible to reach, so flexing the head using the usual techniques will be a challenge.
  3. Restore the mechanism — See below.

ShawnPortsmouthThe RCOG guideline suggests delayed engagement in the pelvis of the aftercoming head should be managed using one or both of the following techniques:

Suprapubic pressure by an assistant should be used to assist flexion of the head. Given our understanding of the head as impacted at the pelvic brim and our goal of restoring the mechanism by rotating the head to assist engagement, we suggest that the goal of suprapubic pressure should initially be to encourage this rotation. This mirrors the understanding we have of suprapubic pressure to resolve a shoulder dystocia by rotating the impacted shoulder off the symphysis pubis. Forcible pressure on an impacted fetal head is unlikely to be beneficial for the baby.

The Mauriceau-Smellie-Veit manoeuvre should be considered, if necessary, displacing the head upwards and rotating to the oblique to facilitate engagement. We use a doll and pelvis to explore why this elevation and rotation prior to re-attempting flexion is necessary. Watch the video below to see this demonstrated.


When a woman is birthing her breech baby actively, we facilitate the head to enter the pelvis using the same principles. Watch the video below, where Midwife Olivia Armshaw is teaching how  to intervene in the case of an extended head at the inlet, when the woman is birthing on hands/knees. In this video, the midwives are discussing how maternal movement – in this case, the woman shuffling her bottom back towards the midwife slightly – helps to elevate the head off the pelvic inlet to facilitate engagement, a technique we learned from the midwives of Sheffield. The principles – elevate, rotate & flex the head – are the same.


Thank you to the Practice Development Team at Portsmouth for organising the day. And thanks to the following midwives for assisting with the day:

  • Claire Reading, midwife in Somerset, who shared her breech experience gained working abroad, and facilitated one of the hands-on stations
  • Olivia Armshaw, midwife from Gloucester, who facilitated one of the learning station and presented on the process of developing a breech team in her local area
  • Tess McLeish, midwife from Lewisham who helped the day run smoothly

Our one sadness on this study day was that we were not joined by any of Portsmouth’s obstetric staff, aside from Ms Arti Matah, who needed to leave early because she was good enough to present at the study day following a night on-call. Across the UK, midwives are trying to engage their obstetric colleagues in a discussion about how to improve things for breech babies and their mothers, and we really need more doctors to come to the table for that discussion to result in a service which is as safe as possible.

Shawn Walker, Olivia Armshaw & Jenny Hall

Shawn Walker, Olivia Armshaw & Jenny Hall

BONUS was meeting and relaxing with Midwife Jenny Hall in Portsmouth after the study day!

— Shawn

Further Study Days are listed under Events. View our Training page for more information.

Feedback from the Study Day:

“the group work was excellent Overall I thought the day was was a good balance of theory to practical”

“very interactive. realistic rather than textbook. real life experiences.”

“perfect study day. Interesting and kept my attention all day!!!”

“visual with the film clips and hands on with the doll and pelvis. Was very good to see normal and abnormal films and great discussion with colleagues to share experiences and what to do in that situation.”

“I also thought Shawn’s attitude to breech was very refreshing. I half expected it to be a bit like “you can have a vaginal breech no matter what”. this was not the case. She had a very safe and sensible approach.”

Assisting rotation of the fetal back to anterior in a breech birth

This post builds on my primary research, Standards for maternity care professionals attending planned upright breech births: A Delphi study. The research reports an experienced panel’s consensus on the skills required for midwives and obstetricians supporting physiological breech births. The practical content of the article is my personal application of one of the findings to clinical teaching.

“Health professionals attending upright breech births should be competent [to assist] rotation of the fetal back to anterior (when the mechanism has deviated from normal)” (p 5). 77% of the panel agreed that this is an important skill. This standard of competence combines two skills: 1) recognising deviation from normal mechanisms; and 2) assisting by restoring the mechanism to normal.

  1. Recognising deviation from normal mechanisms

Within the past two weeks, two people have discussed with me concerns about an incorrect understanding of the correct position for the fetal back when a woman is in a hands/knees position. First, a Practice Development Midwife (PDM) says she advocates teaching breech in ‘only one way’ (eg. lithotomy) because people get confused. A midwife attending training advocated for hands/knees positioning, but when questioned about where the fetal back should be, replied, “The fetal back remains uppermost.” Similarly, a student I am mentoring in practice attended sessions on breech at university. Her lecturer suggested hands/knees may be a more advantageous positioning, but later she is told, even in hands/knees, “The fetal back remains uppermost.” The student had worked out that this couldn’t be correct and sought more information. Excellent critical thinking, Charlotte!

Geburtshilfliche Notfälle, Göbel & Hildebrandt, 2007

Geburtshilfliche Notfälle, Göbel & Hildebrandt, 2007

These are signs of a practice in transition, and the PDM and Charlotte are right to be concerned. Rotating the fetal back uppermost in a hand/knees position is a dangerous but not uncommon mistake. Even in textbooks, such as this German textbook for midwives (Geburtshilfliche Notfälle: vermeiden – erkennen – behandlen, Göbel & Hildebrandt, 2007), the woman’s position is changed, but the professional is still following the rule of, “The fetal back remains uppermost.” (Just to reassure you, once the arms are born, they advocate rotating the fetal body 180° so that the head is born occiput-anterior.)

A physiology-based understanding of the normal mechanisms comes from closely observing spontaneous births which are not interrupted. In a spontaneous breech birth, the most common and most optimal (a.k.a. ‘normal’) rotation of the fetal back is to anterior after the sacrum is born, regardless of the position of the mother.

The simplest way for teaching this aspect of the mechanisms I learned from midwife Jenny Davidson. The baby should rotate “tum to bum.” In other words, the baby’s tummy (stomach/front torso) should be facing the mother’s bum (bottom/posterior), no matter what position the mother is in. If those teaching breech can adopt this language to describe mechanisms and positioning, fewer dangerous misunderstandings, and more flexible thinking mayoccur. Teaching breech as a set of rote manoeuvres leads to automatic behaviours, which are sometimes counter-productive. In my research, I am observing that the path to acquiring breech competence and expertise involves learning to problem-solve in complex, unique clinical situations, often un-learning ‘rules’ that one was taught in skills/drills — because the rules don’t always work (eg. ‘the fetal back remains uppermost’ does not apply in every situation). Experienced professionals replace inflexible rules with more flexible understandings and principles, over a period of time, and through much reflection with peers and mentors. Perhaps teaching should be about patterns and principles, rather than prescriptions?

2. Assisting rotation of the fetal back to anterior — restoring the mechanisms to normal

tum2bumYou should rarely have to do this, but if you do, this principle may be helpful: “Rotation, not traction.” You can assist rotation with your fingers on the bony prominences of the baby’s pelvic girdle, as for any breech manoeuvre. Consider as you do what is happening at the inlet of the pelvis – have the shoulders already engaged, or are they just beginning to enter the pelvic brim?

Safe facilitation of physiological breech births depends on the ability to determine when intervention will be beneficial, and when it is unnecessary and potentially harmful. A breech baby will normally rotate spontaneously, with the back to the anterior (“tum to bum”), as the shoulders engage in the transverse diameter of the pelvic inlet. Pulling or manipulating prior to this spontaneous rotation could cause problems. But if the rotation is to the posterior, it may be beneficial for attendants to intervene at this point rather than rotate an occiput-posterior head mid-pelvis. Or at least 77% of an experienced panel think so …

Shawn

References:

Gibes E & Hildebrandt S (2007) Geburtshilfliche Notfälle: vermeiden – erkennen – behandlen, Thieme

Questions for reflection:

  • Watch the videos in this collection. Identify the normal mechanisms, beginning with descent of the sacrum transverse (to the mother’s side). As you are watching, identify which way you will expect the rotation to occur, anticipating the normal rotation. Did the baby rotate as you expected?
  • Imagine you are attending one of the births in the videos and quietly communicating with a colleague who has no previous breech experience, about what you are expecting to see, and what to document during the birth. What do you whisper to your colleague? Do this simultaneously with your colleague/fellow student as you both watch the video

 

Videos:

Watch this obstetrician (Diego Alarcon) facilitate a complete breech birth. He is touching more than is advocated by physiological breech-experienced providers – the mechanism has not yet deviated from normal – but his hands tell you what he is thinking. The baby’s right foot is behind the left, indicating that rotation is tending in this direction – sacral anterior, good. However, he is closely guarding this. Watch when he puts the forefinger of his right hand on the baby’s right hip bone to ensure that the rotation will occur in a counter-clockwise direction when the contraction begins. His actions are gentle, not forceful, and they work with the mother’s expulsive efforts.

In this birth, as the sacrum is born, it is mostly transverse (normal), but somewhat posterior, to the mother’s left. The baby does not rotate to sacrum anterior, as we would expect as the arms enter the pelvis to be born. The obstetrician (Michel Odent) recognises that the mechanism has deviated from normal and immediately intervenes to restore the mechanism by sweeping down the anterior arm under the symphysis pubis, across the baby’s face.

This video is much more hands-on than a physiological approach, but it provides a good example of a normal mechanism of sacral rotation following rumping when the mother is in a supine position — and how to assist, because the midwife’s (Renata Hillman) hands are positioned to assist rotation using the bony prominences of the fetal pelvis.

Resources and a plug

Posterior arm born, anterior arm high, shoulders in A-P diameter - help is required!

Posterior arm born, anterior arm high, shoulders in A-P diameter – help is required!

In July, Gerhard Bogner of Salzburg presented data at a Breech Birth Network study day.  Although the series is small, the data indicate that when the mother is in all fours position to birth a breech baby, approximately 70% of those births will occur completely spontaneously, eg. without the need to perform assisting manoeuvres at all. Use of upright positioning also reduced the rate of maternal perineal damage from 58.5% to 14.6%, which is actually better than cephalic births!

The reduced need for manoeuvres potentially reduces iatrogenic damage to babies associated with interference at the time of birth, such as birth injuries and inhaled meconium. That’s great for that 70%, but what about the other 30%? The babies born with upright positioning in Bogner’s study had a slightly higher rate of low cord blood gases, indicating hypoxia, although no consequences for the infants or differences in 5 minute Apgar scores were observed.

If a woman is birthing her baby in an upright position, how do we assist the birth confidently and safely when delay is identified? How do upright manoeuvres differ from those performed when the woman is supine? To address a growing need for more practical training in upright breech birth, City University are offering Physiological Breech Birth Workshops in London and taster days around the country. The next one is on 2nd of December at the Whittington in Central London. Lots of hands-on training with a small group of doctors and midwives committed to extending breech skills. We also post conferences and workshops provided by others when we can.

Several people have been in touch to ask about the How and When to Help handout. I disabled the link because it is constantly being updated! Please feel free to download this one and use it in your practice area. But keep in mind understanding in this area is constantly expanding, and this is just one midwife’s current approach. I’m working on research to understand others’ approaches as well, but it will be some time until this is finished.

Look out for two articles appearing this month. In The Practising Midwife, I present a summary of current evidence related to ECV (external cephalic version), with some excellent photos provided by Dr Helen Simpson and Midwife Emma Williams of South Tees Foundation Hospital. In Essentially MIDIRS, Mariamni Plested and I talk about issues in providing innovative care for higher risk birth choices.

Finally, shameless plug: Today (30/9/14) is the last day to vote for my, um, remarkable cousin Jake in the NRS National Model Search. Read all about him here, and then click on the link at the bottom of the article to VOTE FOR JAKE!

Favourite quote from the article: “The funny thing is, some bulls are just like big dogs. They come up to you, put their butt in your face and say, ‘Scratch my butt.’ But as soon as they get that flank rope on them, it’s like, ‘Game on. I’ve got something to do now.'”

Awww. Gotta love a bit of passion, of finding your niche and loving it … We love you, Jake! (Just what every 18 year old boy always wanted, a plug on a breech birth information site. We clearly share a common love of butts.)

Update: He won! Go Jake!

Shawn

Bogner, G., Strobl, M., Schausberger, C., Fischer, T., et al. (2014) Breech delivery in the all fours position: a prospective observational comparative study with classic assistance. Journal of perinatal medicine. [Online] Available from: doi:10.1515/jpm-2014-0048

Shoulder Press and Gluteal Lift

Helping the aftercoming head to flex in upright breech births

When women are in upright positions, many breech births will proceed completely spontaneously because the birth canal follows the flow of gravity. However, the attending clinician may need to assist, either because maternal effort no longer results in steady progress, or because the baby appears compromised and assistance will result in a quicker delivery.  In this blog, I describe one manoeuvre I have learned to help in upright breech births.

The shoulder press is very effective in the following circumstances:

Deflexed head in mid-pelvis

Deflexed head in mid-pelvis

  • The aftercoming head has descended through the pelvic inlet and is either on the perineum (chin visible) or mid-pelvis (chin not visible, but easily reached in the sacral space); and the occiput is anterior
  • The mother is in an upright, forward-leaning position (e.g. all fours or kneeling)
  • The clinician facilitating the birth is behind the mother, and the baby is directly facing the clinician (‘tum to bum’ with mother), with head and body in alignment
When baby's head has descended into the pelvis, the pubic bones are directly behind the occiput

When baby’s head has descended into the pelvis, the pubic bones are directly behind the occiput

In this scenario, the maternal pubic arch is directly behind the baby’s occiput. When pressure is applied to the baby’s torso along the clavicular ridge, guiding the baby’s body straight back through the mother’s legs, the pubic arch will push the occiput up and forward. This causes the aftercoming head to flex and descend, following the curve of the birth canal. The sternocleidomastoid muscles (SCM), responsible for head flexion, attach to the superior aspect of the clavicle and keep the head in alignment throughout this process.

Gluteal Lift – If descents stops with the perineum tight on the baby’s forehead (bregma), and the shoulder press alone has no further effect, an assistant can augment the manoeuvre by lifting the woman’s buttocks up and out. This lifts the perineum over the bregma as the primary attendant performs the shoulder press, moving the baby in the opposite direction. This assisted manoeuvre is especially helpful when the woman is obese, or the perineum is especially tight and intact.

The feeling and effectiveness of this manoeuvre is very easy to replicate using an obstetric model, turned upside down, as in the video below.

Potential benefits

Preserving an intact perineum. An intact perineum helps to maintain beneficial fetal flexion, and routine episiotomy should be avoided for this reason. However, when the aftercoming head has descended onto the perineum, reaching the maxillary or malar bones to perform a modified Mariceau-Smellie-Veit (MSV) can be difficult. Therefore, many clinicians will cut an episiotomy early in order to avoid cutting one while the baby’s face is on the perineum. However, this is not necessary. When the chin is visible, pressure on the maxillary bones through an intact perineum is possible, in combination with upward pressure on the occiput behind the pubic arch, enabling descent to continue. However, the shoulder press is more effective.

The path of the head must follow the arc of the pelvic cavity

The path of the head must follow the arc of the pelvic cavity

Clinicians who are inexperienced or untrained in manoeuvres specific to upright birth will be tempted to pull down on the baby’s torso to deliver the head. However, this does not follow the direction of the birth canal in the same way as the shoulder press as described. Pulling rather than pushing is potentially more likely to result in severe perineal damage, and may also cause cervical nerve damage in the baby due to increased resistance from the intact perineum.

Potential risks

Fractured clavicle. When applying pressure on the clavicle, fracture is an obvious potential risk, although neither I nor those I have learned from have reported fractured clavicles resulting from the use of this manoeuvre. This potential risk can be minimised by spreading the fingers to apply even pressure along the entire ridge, or by applying pressure with fingers or thumbs at the distal aspect, near the glenohumeral joint. The pressure exerted is firm but is not significantly different to that applied when delivering an anterior shoulder in a supine cephalic delivery, and therefore no more likely to result in trauma. The shoulder press minimises the amount of force needed to achieve delivery by promoting maximum head flexion and descent in the direction of the birth canal.

Limitations

The shoulder press as described, on its own, may not resolve a dystocia caused by a deflexed or hyperextended aftercoming head. A very high chin, pointing upwards, identifies a hyperextended head; only the bottom jawbone (resembling a ‘bird beak’) is felt at the very top of the maternal sacrum. If the deflexed head has impacted at the pelvic inlet, the baby’s whole body may need to be lifted in order to flex and/or rotate the head to oblique so that it can enter the pelvis before the shoulder press is useful. Additionally, suprapubic pressure performed by an assistant may help flex the head enough to pass through the pelvic inlet.

Uses

The practice of supporting breech births with the mother in an upright position is somewhat controversial, as minimal research evidence regarding effectiveness exists. Although breech experience is generally at a very low level, most clinicians are only trained to perform lithotomy manoeuvres, and therefore the RCOG recommend lithotomy as the preferred maternal position (RCOG 2006). However, increasingly women are requesting freedom of movement and their own preference to be upright, which is potentially a more satisfying birthing position (Thies-Lagergren L et al 2013). In the absence of evidence that such an approach increases risks, introducing upright manoeuvres into mandatory training will enable this option.

In addition, through discussions with other midwives and participation in the risk management process for various Trusts, I have been informed of several cases of undiagnosed breech births where women were instructed to get onto their backs on their floor following the diagnosis of a breech in labour, due to lack of an obstetric bed in that setting. In some cases, this has been associated with severe delay in delivering the aftercoming head. In true lithotomy, head flexion is promoted by allowing the baby to hang off the end of the bed, where the maternal pubic arch again is responsible for lifting the occiput as gravity gently pulls the baby through the birth canal. This cannot occur on the floor, and the head becomes deflexed. In these cases, the midwives were only trained to perform lithotomy manoeuvres, and instructed that guidelines required them to manage breech births in this way, but the births occurred in settings with no obstetric bed. Providing mandatory training in upright breech to those working in midwifery-led settings will potentially improve outcomes in emergency cases in the short term, and increase maternal choice in the long term.

Sources

I first learned about this mechanism from Dr Anke Reitter, FRCOG, of Frankfurt, Germany, and Jane Evans, an experienced UK Independent Midwife. At the University Hospital Frankfurt a similar technique is called ‘Frank’s Nudge’ after the lead obstetrician, Prof Frank Louwen, who introduced the upright management of breech birth to their unit. I do not refer to the manoeuvre as ‘Frank’s Nudge’ because my technique may differ slightly, and that team has yet to publish their own description of their manoeuvre. Some have described the mechanism as a reflex action, but my hands have experienced it as purely mechanical, and much more effective than Mariceau-Smellie-Veit when women are upright. I can only speak for my experience.

References

RCOG (2006) The Management of Breech Presentation. RCOG Green-top Guidelines, No. 20b. London, Royal College of Obstetricians and Gynaecologists.

Thies-Lagergren L et al (2013) Who decides the position for birth? A follow-up study of a randomised controlled trial.” Women and Birth 26(4): e99-e104.