What is this?
It is a theory developed by a midwife, Jean Sutton, and Pauline Scott, who found that the mother’s position and movement could influence the way her baby lay in the womb in the final weeks of pregnancy. Many difficult labors result from ‘malpresentation’, where the baby’s position makes it hard for the head to move through the pelvis
Why it is important?
Changing the way the baby lies and promoting optimal position of the baby could make birth easier for mother and child. Position ideal for birth is when the baby is lined up so 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’, ie his chin tucked onto his chest, so that the smallest part of his head will be applied to the cervix first. The diameter of his head which has to fit through the pelvis is approximately 9.5 cm, and the circumference approximately 27.5cm. This position is called “occiput anterior” (OA).
The “occiput posterior” (OP) position is not so good. This means the baby is still head down, but facing your tummy. Mothers of babies in the ‘posterior’ position are more likely to have long and painful labors as the baby usually has to turn all the way round to facing the 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 approximately 11.5cm, circumference 35.5cm. This means that often posterior babies do not engage (descend into the pelvis) before labor starts. The fact that they don’t engage means that it’s harder for labor to start naturally, so they are more likely to be ‘late’. Braxton-Hicks contractions before labor starts may be especially painful, with lots of pressure on the bladder, as the baby tries to rotate while it is entering the pelvis.
What position the baby 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. Your belly button (umbilicus) will normally poke out, and the area around it will feel firm. When the baby is posterior, your tummy may look flatter and feel more squashy, 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 in to a concave, saucer-like shape.
Practical steps to avoid posterior positions
The baby’s back is 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, eg 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, eg you are lying on your back or leaning back in an armchair, then the baby’s back may swing towards your back.
Avoid positions, which encourage your baby to face your tummy. The main culprits are said to be lolling back in armchairs, sitting in car seats where you are leaning back or anything where your knees are higher than your pelvis. The best way to do this is to spend lots of time kneeling upright, or 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.
- Watch TV while kneeling on the floor, over a beanbag or cushions, or sit on a dining chair. Try sitting on a dining chair facing (leaning on) the back as well.
- Use yoga positions while resting, reading or watching TV – for example, tailor pose (sitting with your back upright and soles of the feet together, knees out to the sides)
- Sit on a wedge cushion in the car, so that your pelvis is tilted forwards. Keep the seat back upright
- Don’t cross your legs! This reduces the space at the front of the pelvis, and opens it up at the back. For good positioning, the baby needs to have lots of space at the front
- Don’t put your feet up! Lying back with your feet up encourages posterior presentation.
- Sleep on your side, not on your back.
- Avoid deep squatting, which opens up the pelvis and encourages the baby to move down, until you know he/she is the right way round.
- Swimming with your belly downwards is said to be very good for positioning babies not backstroke, but lots of breaststroke and front crawl. Breaststroke in particular is thought to help with good positioning, because all those leg movements help open your pelvis and settle the baby downwards.
- A Birth Ball can encourage good positioning, both before and during labour.
- Various exercises done on all fours can help, eg wiggling your hips from side to side, or arching your back like a cat, followed by dropping the spine down.