BACKGROUND: Epidural anesthesia decreases the core temperature triggering vasoconstriction and shivering, presumably by increasing apparent lower-body temperature. We therefore tested the hypothesis that epidural anesthesia in cesarian delivery patients decrease forearm-fingertip skin-surface temperature gradient and it is cause of shivering. METHODS: Twenty-two healthy pregnant women were studied. Epidural anesthesia was induced by 2% lidocaine and 0.75% ropivacaine 24 ml (T4 level) at 25degrees C ambient temperature. Shivering were evaluated by observation. Core temperature was recorded in the external auditory canal using a compensated infrared thermometer. Arteriovenous shunt tone was evaluated with forearm- fingertip temperature gradients; gradients less than 0 were considered evidence of vasodilation. Skin-surface temperature, skin- temperature gradients (forearm-fingertip, calf-toe) and the presence or absence of shivering were measured. RESULTS: Shivering was observed in seven of twenty two patients. Sixty minutes after induction, Tympanic temperature decreased for 0.8 +/- 0.1degrees C in non-shivering patients and 0.9 +/- 0.1degrees C in shivering patients. Forearm temperature decreased for 0.2 +/- 1.7degrees C in non-shivering patients, but increased for 0.5 +/- 0.6degrees C in shivering patients. Upper limb (Forearm-fingertip) skin Temperature gradients continues the plus in non-shivering patients, but maintain minus (45 minutes after induction) in shivering patients. Low limb skin temperature is increases in both group. CONCLUSION: We failed to confirm our hypothesis, but for an expected reason: shivering was preceded by hypothermia and vasoconstriction in the arm. For prevention of hypothermia in epidural anesthesia, not to be monitored core temperature, but also upper limb skin temperature gradients.