During labour, the position of the foetal head is described in a standard way by relating the lowest part of the foetal head to the four quadrants of the mother’s pelvis (left, right, anterior, posterior). The presenting part of the baby may be the back of the head – occiput (O), when the baby is coming head first, or the back of the baby’s pelvis – sacrum (S), when it is a breech birth. Thus a presentation of the baby’s head may be described as right occipito-anterior (ROA) if the occiput of the baby is facing the posterior aspect of the mother’s right side, or occipitoposterior (OP) if the baby’s occiput is directly facing the posterior part of the mother’s pelvis – this is the most desirable position. LSP would be left sacro-posterior in a breech birth.
(Last modified: 17th Oct 2014)