You will learn about obstructed labour in Study Session 9.
When the baby presents itself in the mother's pelvis in any position other than the vertex presentation, this is termed an abnormal presentation, or malpresentation. The reason for referring to this as 'abnormal' is because it is associated with a much higher risk of obstruction and other birth complications than the vertex presentation. The most common types of malpresentation are termed breech, shoulder, face or brow. We will discuss each of these in turn later. Notice that the baby can be 'head-down' but in an abnormal presentation, as in face or brow presentations, when the baby's face or forehead (brow) is the presenting part.