Fetal Attitude or Posture. The baby that will be delivered safely vaginally has a characteristic posture or attitude. It is folded or bent on itself in such a manner that the back becomes well curved, the head sharply bent (flexed) on the neck so that the chin is almost in contact with the chest, the thighs are bent (flexed) over the abdomen, the legs are bent (flexed) at the knees. The arms are crossed over the chest. This type of posture may partly be due to a process of accommodation to the uterine cavity. This characteristic posture results in a vertex presentation (baby coming out with the centre of the head presenting.)
Vertex presentation. A. Left occipito – anterior. B. Left occipito posterior
When the head is not well bent and the baby is staying like a military man on attention, this results in a sinciput presentation (baby attempting to come out with the forehead foremost)
When the baby bends its head a little backwards it will result in a brow presentation (baby attempting to be delivered with the brow foremost)
When the baby bends its head completely backwards it will result in a face presentation (baby coming out with the face foremost). When the chin of such a baby is pointing to the front, the baby can be delivered normally (mento – anterior face presentation) if the pelvis is adequate. When the chin of the baby is pointing backwards (mento – posterior face presentation) it can hardly be delivered vaginally safely. Such babies are best delivered by caesarean section. Apart from the vertex presentation the other presentation that can cause difficulties during vaginal delivery is shoulder presentation or transverse lie.
In a transverse lie (baby lying across the abdomen), it is the baby’s acromion or tip of the shoulder that presents (makes attempt to come out). Such a presentation is best delivered by caesarean section. A transverse lie can lead to prolapse of the umbilical
cord(umbilical cord drops out of the vagina) which can lead to the death of the baby if the baby is not delivered by caesarean section speedily.
Another presentation that can cause difficulties during birth is breech presentation (buttocks or lower limbs coming out first). Prolapse of the umbilical cord and/or trapping of the fetal head are complications that can lead to fetal death or severe injury if breech delivery occurs inappropriately. Fetal and/or maternal injuries can also occur during breech delivery. It is recommended that if the breech is presenting in a first timer, she should have a caesarean birth. It is a safe approach to delivery. In other situations, the pelvis should be assessed by an expert. If found to be adequate, the woman can be delivered vaginally using for example assisted breech delivery approach.
