The breech and the perineum

In an active breech birth, we aim to support and encourage the physiological process as long as it appears to be safely unfolding. When practising in this way, we have to understand why some variations occur, when they may threaten the safety of mother or baby, and how clinicians might intervene to safely assist the birth when necessary. 

Breech deliveries are not associated with an increased incidence of severe perineal damage (Jones 2000), and compare favourably to instrumental cephalic deliveries and persistent posterior positions. However, in a lithotomy (supine, legs in stirrups) breech delivery, episiotomies are commonly used to assist with manoeuvres. Manual assistance at some stage is almost always necessary when women are in this position, and an early episiotomy is considered by many to be beneficial. So much so that ‘inappropriate avoidance of episiotomy’ has been identified as a common mistake in breech simulation exercises (Maslovitz et al 2007). However, current RCOG guidelines indicate that episiotomies should not be performed as a matter of course, but according to clinical indication. So what are these indications?

In contrast, active breech births (where women assume upright positions) are associated with lower rates of perineal damage than cephalic births. In a recent study (Bogner et al 2014) comparing a small series of all fours breech births with lithotomy deliveries, serious perineal lacerations occurred only 14.6% of the time when women were in all fours, compared to 58.5% of the time with lithotomy deliveries. A majority in the latter category were due to episiotomies, rather than the mechanical process of birth.

The breech stretches a perineum differently from a head. A well-flexed, round head will displace the fanning perineum more or less evenly, spreading the tissue during the crowning process. In contrast, a bottom is softer and flatter. And other limbs provide irregular pressure.

When might intervention be helpful?

I became interested in this question due to differing information from several experienced clinicians. Mary Cronk MBE, with whom I had the great privilege to teach a few years ago, explained in her inimitable way that she was a bit more ‘scissor-happy’ with breech babies, so there must be good reason. However, other experienced clinicians feel that an intact perineum is important to maintain fetal flexion for as long as possible, and needing to cut an episiotomy should be a very rare occurrence. (See a previous discussion.)

One of Mary’s classic slides includes a birth where she cut an episiotomy because the perineum had become overstretched and was tearing in a button-hole pattern. Especially when nulliparous women give birth to frank breech babies, this overstretching may occur because the perineum does not spread and recede over the comparatively flat bottom in the same way as it does a head.

If the perineum has become abnormally distended and is causing significant delay, consider a 'perineal sweep.' If not successful, an episiotomy is indicated.

If the perineum has become abnormally distended and is causing delay, consider a ‘perineal sweep.’ If not successful, an episiotomy is indicated.

The illustration to the right depicts an abnormally distended and overstretched perineum. The baby’s bitrochanteric diameter (the distance between the outer points of the hips) has already descended past the ischial spines, and we have passed the ‘point of no return’ – the baby will be born vaginally.

The potential risks with an abnormally distended perineum are:

  • Delaying the birth at a point when the umbilicus has already descended into the pelvis and may be compressed. The fetal heart may no longer be reliably auscultated due to descent into the pelvic brim. If this is the case, assistance is warranted.
  • A button-hole tear in the mother’s perineum.

Are there alternatives to episiotomy?

When we recently met up at the RCOG and Oxford Breech Conferences this October, I asked Anke Reitter what she would do if she felt that a tight perineum was holding up a birth at a crucial point. She described to me what might be called a ‘perineal sweep.’ Similar to a cervical sweep, (with consent) the clinician inserts one finger between the breech and the tightly applied perineum, and sweeps around the perimeter, encouraging the border of the perineum to recede over the presenting part and allow the birth to proceed. She explained that this often causes progress to resume without the need to perform an episiotomy.

I found this really helpful to consider as part of my breech midwifery toolkit. As we re-develop our professional cultural knowledge about breech, it is important we continue to talk about what we do and how we do it, even those skills we feel will be rarely needed. While we strive to create the conditions for those 85% of women to give birth to their breech babies over intact perineums without assistance, we also have to be able to recognise the perineum/bottom combination which may occasionally present a problem, and how we might address this for the best possible outcome.

I would love to hear your thoughts and experiences.

Shawn

Update, October 2016: This would be a good topic for a systematic review. Bogner’s study demonstrated that breech deliveries (supine & upright) had the lowest rate of perineal trauma AND highest rate of episiotomy in the local population (eg. compared to cephalic births). I have seen Bogner’s statistics (eg. simultaneous lowest rate of perineal trauma AND highest rate of episiotomy in the population) replicated in an audit from Sydney, and now again in this study out of Pakistan. Please be in touch if you are looking for a systematic review topic and would like to collaborate.

Jason S, Khan Jadoon S, Shah R. Maternal and neonatal complications in term breech delivered vaginally. Journal of the College of Physicians and Surgeons–Pakistan : JCPSP. 2008 vol: 18 (9) pp: 555-8

10 thoughts on “The breech and the perineum

  1. Joy Horner

    Most if the breech births I’ve attended, like the cephalic births I attend, do not seem to sustain much perineal injury. I did consider doing one on a primip birthing her breech in an upright position. She was a horse rider, so maybe her perineum was stronger, or maybe it was that her baby was large at 9lb 10oz. She birthed beautifully but baby was stuck at the forehead for a while. Mary Cronk and I flexed the baby’s head and manually massaged the perineum upwards. Just as I was considering episiotomy the perineum spontaneously tore and the baby was born.
    I did perform an episiotomy on a woman birthing her breech baby when the head didn’t spontaneously birth on all fours. She was a primip and the head was stuck at the brim with the body born. All the usual manoeuvres, and change of maternal position had failed and we were running out of time. The shoulders were tight against the perineum (similar to a shoulder dystocia) and I wanted more access to try an internal manoeuvre. I still couldn’t free the head (which was later released with a change in position). I felt awful that I’d done an episiotomy (my only one in the last 12 years of practice). In my book it is only ever a lifesaving manoeuvre.

    Reply
    1. midwifeshawn

      Joy, thank you so much for your honesty and candour, as always. So much to learn! I’ve had a few of those tricky perineums when the head is almost born, and lately I’ve been wondering if it is in fact *just* perineum. I wonder if sometimes the vertex catches on the bottom of the sacrum as well, as per the image below. Would be interested to know your thoughts.

      Fetal head at the pelvic outlet

      Reply
  2. Peggy Seehafer

    I would fear levator ani injuries with that abnormally distended perineum. As an alternative is it common to hold the babys butt back while “crowning” as long as possible (depends on the heartbeats) and the pelvic floor will be gently opened i the same way as in cephalic presentation.

    Reply
    1. midwifeshawn

      Hi, Peggy. I am concerned about this perineum as well. It is not common to hold the baby’s butt back in the UK. Most breech attendants practice ‘hands-off’ until a delay is diagnosed. For almost all of the breeches I’ve attended, the perineum has gently opened in the same way as a cephalic presentation, so holding the bottom back is clearly not required for this to occur. In a physiological birth the philosophy is to not interfere unless assistance is required, so this article is part of the attempt to discern when such assistance is required. Always interested to hear about differences in practice, though, and very glad you’ve contributed this to the discussion.

      Reply
  3. Rixa Freeze

    Hi Shawn, as I’m working my way through the VCOP course, it led me over to this post. I was wondering what you meant by this phrase in the last paragraph: “simultaneous lowest rate of perineal trauma AND highest rate of episiotomy in the population.” I thought that Bogner’s study had low rates of perineal trauma & also *low* rates of episiotomy for women in the all-fours position.

    Reply
    1. midwifeshawn Post author

      Hi, Rixa. Thanks for this. I’ve edited the paragraph slightly to clarify. Bogner’s study included upright and supine births. The low rates of perineal trauma among the women who birthed upright were combined with the high rates of episiotomy and consequent perineal injury among those who birthed in a supine position. But still, compared to cephalic births in the same population, those who birthed breech babies sustained the least amount of perineal injury.

      Shawn

      Reply

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