Optimal fetal positioning is an important topic for pregnant women to learn about.
Sometimes, longer, more painful labours and even c-sections result from malposition, where the baby’s position makes it more difficult for his or her head to move through the pelvis.
I’m sure you’ve heard about babies being ‘stuck’ before.
Some women have even been wheeled off for emergency caesareans with a diagnosis of CPD (cephalo-pelvic disproportion) – or in simple terms, the mother’s pelvis being too small – only to find baby was simply posterior or malpositioned.
The actual incidence of true CPD is quite low. Read more about CPD.
Why Is Optimal Fetal Positioning Important?
Influencing the way the baby lies and promoting optimal fetal positioning of the baby could help to make the birth easier for mother and child.
Ideally, your baby will be lined up as to fit through your pelvis as easily as possible.
To be in this position, baby needs to be head down, facing your back, with his back on one side of the front of your tummy.
In this position, the baby’s head is easily ‘flexed’, i.e. his chin tucked into his chest, so that the smallest part of his head will be applied to the cervix first.
This position is called ‘occiput anterior’ or in shorthand (OA).
The ‘occiput posterior’ (OP) position is not as ideal. In a posterior position, the baby is still head down, but facing your tummy instead of your back.
Are Posterior Labours More Painful?
Mothers of babies in the ‘posterior’ position are more likely to have longer and more painful labours (backache labour) as the baby usually has to turn all the way around to face your back in order to be born.
He cannot fully flex his head in this position, and diameter of his head, which has to enter the pelvis, is greater.
This means that often posterior babies do not engage (descend into the pelvis) before labour starts.
The fact that they don’t engage means that it’s harder for labour to start naturally, so they are more likely to be born post-dates.
Braxton Hicks contractions before labour starts may be especially painful, with lots of pressure on the bladder, as the baby tries to rotate while it’s entering the pelvis.
Sometimes a low anterior placenta can be the reason why a baby is posterior.
How Do I Know What Position My Baby Is In?
When the baby is anterior, the back feels hard and smooth and rounded on one side of your tummy, and you will normally feel kicks under your ribs.
When the baby is posterior, your tummy may look flatter and feel more squishy, and you may feel arms and legs towards the front, and kicks on the front towards the middle of your tummy.
The area around your belly button may dip into a concave, saucer-like shape.
How Do I Avoid A Posterior Presentation?
The baby’s back is on the heaviest side of its body. This means that the back will naturally gravitate towards the lowest side of the mother’s abdomen.
So if your tummy is lower than your back, e.g. if you are sitting on a chair leaning forward, then the baby’s back will tend to swing towards your tummy.
If your back is lower than your tummy, e.g. if you are lying on your back or slouching on a sofa, then the baby’s back may swing towards your back.
Avoid positions which encourage your baby to face your tummy.
The main culprits are slouching in armchairs, reclined on a car seats, or anything where your knees are higher than your pelvis.
The best way to do this is to spend lots of time kneeling upright, sitting upright, or on hands and knees.
When you sit on a chair, make sure your knees are lower than your pelvis, and your trunk should be tilted slightly forwards.
For more information on optimal fetal positioning, be sure to visit the Spinning Babies website.