TY - CHAP M1 - Book, Section TI - Labor Analgesia A1 - Hannallah, Medhat A1 - Kwock, John A2 - Freeman, Brian S. A2 - Berger, Jeffrey S. Y1 - 2016 N1 - T2 - Anesthesiology Core Review: Part Two Advanced Exam AB - In the first stage of labor, pain is carried on visceral afferent type C fibers that travel with sympathetic nerve fibers to the cervical and uterine plexuses, then the hypogastric and aortic plexuses, before entering the spinal cord from T10 to L1. Pain originates from stretching of the lower uterine segment and dilation of the cervix. At this point in her labor, the mother will generally feel pain referred to her lower abdomen, but as labor progresses it may be referred to the lumbosacral area, gluteal region, and thighs. Later in the first and into the second stage of labor, pain is also transmitted by somatic nerves, namely the pudendal nerves, which enter the spinal cord from S2 to S4. Thus, adequate analgesia for the second stage of labor requires blockade of T10–S4. Pain at this point is the result of stretching the pelvic floor, vagina, and perineum. The pain of labor is usually described as moderate to severe, with the intensity of pain corresponding with increasing cervical dilation and more frequent and intense contractions. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=1135742980 ER -