Face presentation occurs when the baby's neck is so completely extended (bent backwards) that the occiput at the back of the fetal skull touches the baby's own spine (see Figure 8.5). In this position, the baby's face will present to you during delivery.
Refer the mother if a baby in the chin posterior face presentation does not rotate and the labour is prolonged.
The incidence of face presentation is about 1 in 500 pregnancies in full term labours. In Figure 8.5, you can see how flexed the head is at the neck. Babies who present in the 'chin posterior' position (on the right in Figure 8.5) usually rotate spontaneously during labour, and assume the 'chin anterior' position, which makes it easier for them to be born. However, they are unlikely to be delivered vaginally if they fail to undergo spontaneous rotation to the chin anterior position, because the baby's chin usually gets stuck against the mother's sacrum (the bony prominence at the back of her pelvis). A baby in this position will have to be delivered by caesarean surgery.