Pelvis Type Most Likely to Have Op Baby

Updated: February 2022

How many times have you heard "I had to accept an epidural/c-section/ventouse/etc. because my infant was facing the incorrect fashion"? An occipito posterior (OP) position occurs when the infant enters the pelvis facing forward with their back towards their mother'south dorsum. The back of the baby's head (the occiput) is in the back of the pelvis (posterior) against the sacrum. Between fifteen-thirty% of babies kickoff labour in an OP position, but less than five% will remain in this position at birth (Sizer & Nirmal 2000). An OP position is associated with medical intervention during labour: syntocinon infusion; epidural; forceps; ventouse; c-department. This post volition discuss whether an OP position is actually a problem, or if the trouble lies in our beliefs about, and 'management' of this common variation.

A flake of anatomy and physiology

I'grand assuming that readers of this blog are midwives, doulas, and/or birth nerds who have an understanding of the pelvis. If yous don't, it doesn't really matter – knowing the names of the basic doesn't help yous sympathize how the pelvis works. Basically, the pelvis is shaped in a fashion that requires the baby to rotate during labour. If you look in textbooks you will find diagrams with exact measurements of various pelvic diameters – this is nonsense as every woman'southward pelvis is different and they don't come in 'types' (Betti & Manica 2018; Kuliukas at al. 2015; Tennenhouse 2018).

I find it more than helpful to consider that there are three areas of the pelvis: the brim, the cavity and the outlet. These areas have slightly different shapes, every bit I've tried to demonstrate beneath: The baby usually enters the skirt with their caput more often than not facing sideways ie. transverse (to fit the shape). It doesn't actually matter which way the baby's head is when inbound the brim – in one case the caput is in the cavity the baby can rotate. The downward pressure of the contractions, and the tension and shape of the pelvic muscles will guide them into a direct occipito anterior (OA) position and through the outlet. All the same, a very minor number of babies will rotate to a directly OP position and come up out facing the front of the pelvis (see below).

Usually, the baby will accept the shortest rotation into a direct OA position. So, a babe inbound the pelvis in a ROA (back = front/right) does this:

Whereas a baby inbound the pelvis in an ROP (back = back/right) position does this:

Of course OP and OA babies may apply this turning infinite to do all kinds of interesting things from turning OA to OP, to rotating all the fashion effectually the back of the pelvis to terminate up OA. The babe will piece of work out the all-time mode to motion through their female parent – even if nosotros don't understand information technology.

Beingness born OP

Some babies are born in the OP position either because they stay in that position, or because they rotate into that position during labour (from OA). You tin can watch the birth of a big OP baby in 'The Birth of Boyfriend'.

The 'bug'

OP labour patterns

Labour patterns are often different with an OP baby. This is a physiological variation and is perfectly normal. It is important to understand why and how physiology differs with this position. It is hard plenty for a woman with a infant in an OA position to fit prescribed patterns of labour progress and fifty-fifty more than hard with an OP position—particularly with a first babe.

Firstly, a infant who enters the brim in an OP position may non fit quite then snuggly on the cervix and this may increment the chance of variations such as 'mail-dates' pregnancy and/or rupture of membranes before labour. Early on labour (the separation phase) can take longer to build with more stops and starts. In one case in strong labour, the woman's contraction pattern is likely to be irregular.

These situations only become problematic when we employ generalised expectations about how labour should be to an individual woman/baby and state of affairs. It becomes more than of an issue if vaginal examinations are used to assess progress. With an OP labour, the fundus forms in the aforementioned way as with an OA labour. Even so, the cervix is not held open up similar it is with a well-flexed OA babe. Therefore, it appears non to exist opening if yous experience it – resulting in an incorrect diagnoses of 'failure to progress.' Instead this is a failure to understand the transformation of the uterus during labour.

Here is how the fundus/cervix office with an OA baby (once I discover my lost apple tree-pencil I'll create an OP version).

The key difference with an OP baby is that the cervix is not held open until the babe enters the pelvic cavity and rotates (or not). The mutual design is that the cervix appears to be not doing much while the fundus is decorated forming. Then one time the baby descends and rotates, the soft and stretchy neck gets quickly pulled up. The birth is ofttimes very quick once this happens (if physiology has been supported rather than disrupted with interventions to 'speed up' the opening of the cervix).

An 'early' urge to push is also a normal aspect of OP labour. Equally the OP baby descends through the pelvis the dorsum of their head puts pressure on nerves creating an urge to push. This pushing may be the body's way of helping the baby to rotate by increasing downward pressure onto the neck and pelvic muscles – the babe tin can pivot against this tension. An anterior cervical lip is besides common.

Interventions

Trying to make labour patterns (women) conform

If cervical dilatation is being used to assess labour progress it is very likely that 'failure to progress' will exist diagnosed. The medical response to this is to interruption the waters if they are however intact. This reduces the corporeality of fluid around the baby, reducing their ability to rotate. The adjacent step is to augment the labour with syntocinon (pitocin) which increases pain (and use of epidural) and the gamble of fetal distress.

The alternative approach is to employ non-medical interventions to go the woman'southward torso to fit institutional non-evidence-based parameters of progress. Midwives, doulas and birth workers oftentimes intervene with techniques and directly women into various positions aimed at getting the babe to rotate quicker. In that location are no studies demonstrating these interventions are effective for women having a physiological birth ie. without an epidural (Desbriere et al. 2012).

Regardless of the type of intervention — medical or culling — the underlying beliefs/principles are the same:

OP is a malposition that requires intervention (the adult female's body is wrong).
That women's bodies demand to be intervened with to fit medical timeframes rather than disregarding those timeframes.
External proficient cognition and skills are more powerful than women's instincts and intuitive motility.

Pain?

Some women volition experience pain differently when their baby is in an OP position. However, it is difficult to determine if this experience of pain is due to the position of the baby, or other factors. A study past Lee, Kildea & Stapleton (2015) into back pain in labour ended: "The assumed relationship between fetal position and dorsum pain in labour is a dominant soapbox, albeit one which is lacking in empirical credibility."Enough of women with an OA infant complain of backache in labour, whilst many with an OP baby do not. Unfortunately, women are told that OP labour is 'worse', and are told horror stories like the 1 I started the post with. Given the psychological and emotional attribute of hurting perception, this cannot be helpful. Every birth experience is also dissimilar. I cared for a female parent during two births. Her first baby was in an OP position and she had a four-mean solar day finish-showtime blueprint before labour established. Apart from being tired, she coped well with the pain throughout. Her second baby was OA and labour established apace. She was shocked and distressed by how much more pain she experienced with her OA baby compared to her previous OP baby.

Women with an OP baby are more likely to opt for (or exist persuaded to have) an epidural. This is not surprising, considering they are led to believe their labour will be more painful. They are also more likely to exist subjected to interventions that increase pain and risk. For, example, a adult female with an OP baby is more likely to be told her labour is wearisome and have augmentation. Both medical methods of augmentation—ARM and/or syntocinon (pitocin) increase pain. Once an epidural is inserted, the ability of the baby to rotate into an OA position is reduced (Lieberman et al. 2005). The woman is unable to instinctively move her body and work with her baby to facilitate rotation. In addition, the pelvic 'flooring' (more like a bowl shape) is anaesthetised and loses its tone, taking away the resistance that assists rotation. In this situation (ie. non-physiological labour), positional interventions may help to rotate the babe (Bueno-Lopez et al. 2018).

In terms of back hurting during labour (regardless of baby'south position), sterile water injections (into the skin of the lower back) are effective in providing relief (Fogarty et al. 2008; Lee et al. 2017).

Suggestions

Pregnancy

Women tin can blame themselves for their baby being in an OP position. They question what they did (spent too long in the motorcar) or didn't do (scrub floors). Often the advice they are given antenatally about 'optimal fetal positioning' implies that they have command over the position their infant is in when there is no research show to back up this notion. In fact, the little research that has been washed demonstrates that hands and knees posturing in pregnancy makes no difference (Hunter, Hofmeyr & Kulier 2009; Kariminia et al. 2004). I have fifty-fifty heard of women being told that their baby has assumed an OP position because of their unresolved emotional issues!

Pregnancy is a fourth dimension to build and nurture self-trust, to reinforce the woman every bit the expert. Non a fourth dimension to disempower her and reinforce fear and external expertise. Intendance providers should:

Reinforce the adult female'due south trust in her trunk and babe to nascence.
Discuss the possibility that her labour may be dissimilar (not amend or worse) and might not fit general expectations nearly labour patterns/progress.
If she wants to, she tin effort a variety of techniques to encourage the infant to turn (even though the research suggests it will probably be ineffective). However, if the baby doesn't reply, it's because they have called their optimal position for labour. The baby knows the shape of their mother's pelvis better than whatever care provider.
Remind her that the baby will turn once he gets into the pelvic cavity in labour, or may fifty-fifty be born OP.
Tell her positive OP birth stories and connect her with other women who have experienced positive OP labours.

Labour

Trust the mother and her infant to birth.
Provide an environment where she can instinctively move and work with her infant to facilitate rotation.
Don't practise vaginal examinations. They are ineffective at determining labour progress with an OA infant, never listen an OP one.
Don't tell her not to push if she is spontaneously pushing—regardless of cervical dilatation (again – don't do a VE).
Back hurting can be relieved by a forward-leaning position (Stremler et al. 2005); warm water; gentle sacral pressure or sterile water injections. Avoid applying strong force per unit area to the sacrum as this may reduce the space available in the pelvis for rotation.
If the woman requests help or would prefer you to 'exercise' something, there are several techniques yous can use to create more space in the pelvis. I take provided a list here. Note that these techniques/positions are nigh increasing the space in the pelvis rather than rotating the baby – they provide an opportunity rather than making the baby movement. And they are interventions.
Occasionally, despite everything, a babe will go 'stuck'… and this happens to babies in an OA position too. In this situation, more invasive interventions such equally digital rotation (Ray et al. 2018); instrumental birth or c-section may be necessary. However, virtually of the fourth dimension, these interventions are carried out due to 'failure to await' rather than a genuinely stuck baby.

In summary

An OP position is not wrong or a problem. It is not caused by anything the adult female does or does not do. Instead, information technology is a common variation that occurs when a baby gets into the 'optimal position' for their journeying through their mother'due south unique trunk. After all, the baby has more cognition about the interior of their mother's pelvis than we do. If nosotros want to amend the experience and outcomes associated with an OP position we need to rethink our approach to it. Let'due south celebrate the OP baby'due south wisdom and allow the birth to unfold as it needs to, only intervening if information technology is truly required.

Further resources:

Pushing and Cervixes – The Midwives' Cauldron Podcast

Learn more about Childbirth Physiology in my Online Class

kissingerloneve77.blogspot.com

Source: https://midwifethinking.com/2016/06/08/in-celebration-of-the-op-baby/