Figure 58-7 Distribution and intensity of labor pain during each stage of labor and delivery. In the early first stage (A), pain is referred to the T11 and T12 dermatomes. During the late first stage (B), pain also extends to the T10 and L1 dermatomes. In the second stage (C), in addition to the dermatomal distribution of late first stage, pain is also felt as pressure in the lower part of the back and perineum and the upper part of the legs. During the end of the second stage and for delivery (D), pain originates from the perineum. (Redrawn from Bonica JJ: Obstetric Analgesia and Anesthesia. World Federation of Societies of Anesthesiologists. Seattle, University of Washington Press. As modified by Bonica JJ: The nature of pain in parturition. In Van Zundert A, Ostheimer GW [eds]: Pain Relief and Anesthesia in Obstetrics. New York, Churchill Livingstone, 1996, p 32.)