Posterior Position of Baby

Occiput posterior (Occiupt = head / Posterior = Back aspect of the women) concerning babies back

Posterior position of Baby- When the baby enters the pelvis facing forward with its back towards the mothers back (Diagram 1).

Diagram 1

Poor posterior positioned babies have developed a bad wrap for themselves over the years to be ‘hard’ labours. Another common name is ‘back labour’.

This infamous reputation is because anatomically when the baby is posterior and trying to fit out of a vagina the shape of the head is different to if it was anterior. The differences include;

The head circumference is bigger.
The skull bones don’t ‘mould’ as easily when receiving the pressure from the contractions on the cervix.
The head pressure on the cervix is uneven which tends to make the cervix dilate more unevenly than it should.

These factors can tend to cause a variety of issues- ESPECIALLY when these women are birthing in the hospital system.

Potential ‘issues’ for a Posterior Positioned Baby

- ‘Post dates’ pregnancy

Due to the shape of the head when in the posterior position, this can prevent the ability for bubs head to be able to enter the pelvis and ‘sit’ on the cervix to help stimulate labour. This is the normal physiological process to birth a posterior baby vaginally. Hold trust in your body, and trust in the process.

- Rupture of membranes before labour
- Long start-stop pre-labour phase (often called spurious labour)

This is a natural physiological process that babies in OP position need to have a functional, vaginal birth. Once again hold trust in your body, and trust in the process. As long as your ligaments are balanced the position your baby is in right now is the RIGHT position for your body, pelvis and baby.

- Irregular contractions during labour

Normal, normal, normal. This is what your body and baby needs to birth a posterior baby vaginally.

- Slower cervix dilation while rotation takes place

As above

- Early urge to push

The urge to push is created when the hard surface of babies head descends into the pelvis enough to put pressure on the rectum & pelvic floor through the vaginal wall. This early pushing urge happens in 20%-40% of vaginal births and 41% of babies in an OP position.

This early urge can be a normal physiological process of the body.

Once the baby has entered the ‘brim’ of the pelvis (the top entry of the pelvis) it enters the ‘cavity’. This cavity is a wide space in the pelvis where rotation of babies position can occur. The early urge to push whilst baby is in the space enables the baby’s head to be firmly applied to the pelvic floor which facilitates rotation and flexion of the baby into the optimal position.

Now, this is all well and good when mama doesn’t have an expectation of how her birth ‘should’ go and has a midwife that supports & understands the natural process of birth inclusive of the many variations of ‘normal’ birth however, that is not always the case.

In the hospital system, we run off a study performed in the 1950s by a man named Friedman including 100 women giving birth to their first babies. This study concluded that on average, first-time mamas dilate at 1.2cm/hr.

Unfortunately, our hospital policies to this day are based more or less on this study.

This is incredibly unfair for women.

It applies a lot of pressure, intimidation, rush & therefore adrenalin, to a natural physiological process, that doesn’t respond well to any of those emotions.

Before I start a tangent on this topic lets bring it back to OP babies.

When women come into hospital in either ‘established’ labour or ‘spurious’ labour they are automatically on a timer and expected to progress at a certain rate that ‘apparently’ every woman has to, to have a ‘normal’ vaginal birth. When a mother is experiencing HER normal physiological OP positioned labour, she is often made to feel like her body isn’t ‘keeping up’ to the expectation of normal birth.

This can often lead to intervention taking place such as;

Artificial rupture of membranes (breaking waters)

This makes it harder for bub to rotate in the ‘cavity’ of the pelvis, & often more painful when they are rotating.

Augmentation of contractions with syntocinon

This often pushes baby into a position of being stuck as it has not had the breaks between contractions that it needs to wiggle, flex its head and rotate its body.

Epidural

Relaxes the pelvic floor often too much so that baby now cannot push its head up against it and utilise it as a guide to rotate into the optimal position.

Posterior Bub Position Facts

Between 15-30% of babies start labour in an OP position, but less than 5% will remain in this position at birth (Sizer & Nirmal 2000).
Every woman’s pelvis is different.
Without help, almost half of women will give birth to their posterior babies.
Epidural anesthesia increases the rate of posterior position at the time of birth from about 4% up to about 13%.
Low thyroid function is associated with fetal malposition such as posterior or breech.

How can you avoid a Posterior positioned Bub

You’ve come to the right place, my friend.

A lot of babies who are in a posterior position can be due to the imbalance in the ligaments, muscles and tendons surrounding the uterus and pelvis. The ligaments can be tight and misguide bub.

This is what most of my work revolves around and I have several programs for pregnant women to help with this:

As mentioned above- sometimes no matter what you do, some babies are just meant to enter their labour in the posterior position.

So you are having an OP labour..

..Because your body has guided bub into that position for whatever physiological reason. The fact is, the physiological process of your birth will most likely be longer & more painful (if that is how you perceive) than if bub was in OA.

Some relieving techniques to perform in labour that can be helpful,

Listening to your body and what positions it is telling you to get into- could be upright on your side, upside down- no limits
Water for injection in your lower back
Sacral pressure can feel good
Counter pressure on your iliac crest
Heat packs on your back
Water submersion
Shower water pressure on your sacrum