ABSTRACT
The mechanisms involved in normal parturition are not completely understood. Less well understood are the mechanisms responsible for the timing of parturition. The time at which parturition occurs is tightly controlled, to ensure optimal survival of the newborn. There are multiple causes of preterm birth. The proximal causes of preterm birth may be different than the causes of normally timed parturition, even if the final common pathways are similar. By way of example, prematurity due to polyhydramnios, cocaine use, infection or preterm membrane rupture likely have different mechanisms, even though final pathways for uterine contractions and cervical dilation may be similar.
