One of the mysteries of mammalian reproduction is the physiologic process that determines the length of gestation. The proper timing of birth ensures that the young individual is sufficiently developed to survive and adapt in the extrauterine environment, and that the mother is capable to provide nutrition and protection to the newborn. This volume summarizes new knowledge obtained by many researchers seeking to unravel the compile mechanisms that contribute to the maintenance and termination of pregnancy. The most important common goal of these efforts is to reduce the incidence of...