“…The stretching of the birth canal as the fetus descends activates innervating sensory fibers, sending signals through the spinal cord to the brain thereby causing the release of various neurochemicals ( e.g. , Ferguson's reflex; Levy et al, 1995; Berkley, Robbins & Sato, 1988; Berkley, Hotta, Robbins & Sato, 1990; Robbins, Sato, Hotta & Berkley, 1990; Krehbiel, Poindron, Levy & Prud'Homme, 1987; Ferguson, 1941). These neurobiological changes facilitate the birth process and are involved in changes in emotionality and induction of maternal behaviors (Kendrick et al, 1991; Da Costa et al, 1999; Levy, Kendrick, Keverne, Piketty & Poindron, 1992).…”