Prolonged labor is defined as the total duration of the first and second stages exceeding 18 hours, often resulting from factors like inadequate cervical dilation or descent. The latent phase, which precedes active labor, can last longer than 20 hours in primigravidae or 14 hours in multiparae without immediate risk to the mother or fetus, warranting expectant management. Identifying the underlying causes is crucial for appropriate treatment, which may involve medical intervention such as oxytocin or cesarean delivery if necessary.