Manual Rotation
When labour begins, the baby’s head will usually enter into the pelvis looking sideways. As the head descends and hits the pelvic floor, it should rotate to face down (occiput anterior or OA). This is the optimal position for delivery. Sometimes, it will face down and a bit to the right or left (ROA or LOA). This is fine as well.
Sometimes, babies descend into the pelvis facing up (occiput posterior or OP). This if often associated with a longer labour and more back pain. Pushing takes longer and the baby will usually need to rotate to a face down position before the delivery can happen, as the presenting diameter is larger when the baby is OP. When there is a lot of room in the pelvis, or if the baby is very small, it can sometimes be born ‘sunny side up’.
If the baby remains stuck looking sideways to the right or left (ROT or LOT), this can be a sign of the baby being too big or the pelvis being too small, and this is called a 'deep transverse arrest’.
There is not much that can be done about the baby’s position until the woman reaches 10cm of dilatation. When a woman is fully dilated and pushing, the OB may be able to manually turn the baby’s head into a more favourable position, as this will make the pushing a lot more effective. An epidural is usually required for this procedure.