By Dr J Kabyemela, MD Labour does not always proceed according to expectations. Moreover, in the majority of instances, the difficulties are neither predicted nor anticipated. In normal labour, there is a short latent phase characterized by abdominal discomfort, low backache and irregular tightenings, which get progressively stronger and more painful. This experience varies widely. Once labour is established, the principal guiding parameters of progress are the dilatation of the cervix and the descent of the baby's leading part, usually the head, into the pelvis. By the time the cervix dilates to its maximum (10 cm), the first stage of labour is completed and the second stage commences. This stage, which should be much shorter than the first, includes maternal efforts for the first time, in the form of pushing and actual delivery. There is, of course, the third stage of labour, which is concluded by delivery of the placenta (afterbirth). As anyone can envisage, there are many things that can go wrong to turn a routine labour process abnormal. The uterus may not contract effectively, making labour abnormally long; it may contract too vigorously, causing fetal distress; the cervix may fail to open beyond a certain point; or the leading part may not descend beyond a certain level in the pelvis effectively arresting labour. Many other things can go wrong, as we shall see shortly. For many of these problems, remedial measures are available. For some, labour may have to be abandoned, resorting to caesarean section. Remember, once labour is established, delivery is inevitable. However, as a golden rule, nobody can guarantee anybody a vaginal delivery at the onset of labour. Every labour can potentially go wrong. In recent times, up to a third of all pregnancies are delivered by caesarean section. Only half of these are planned (elective); the rest are emergencies, mostly because of problems in labour.