9Alehagen S, Wijma B, Lundberg U, et al. Fear, pain and stress hormones during childbirth. J Psychosom Obstet Gynaecol, 2005,26 : 153-165.
10ACOG Committee on Obstetric Practice. ACOG Committee Opinion number 269 February 2002. Analgesia and cesarean and delivery rates. American College of Obstetricians and Gynecologists. Obstet Gynecol, 2002,99 : 369-370.