Pregnancy at term does not alter the responses to a mechanical and an electrical stimulus after skin EMLA application.

Author(s): Katafigioti A, Paraskeva A, Petropoulos G, Siafaka I, Fassoulaki A

Affiliation(s): Department of Anesthesiology, Aretaieion Hospital, Medical School, University of Athens, Athens, Greece.

Publication date & source: 2009-06, Middle East J Anesthesiol., 20(2):251-5.

Publication type: Randomized Controlled Trial

BACKGROUND: Pregnancy is associated with reduced local anesthetic requirements and increased pain thresholds, possibly due to hormonal changes and activation of endogenous opioids. METHODS: We compared the responses to a mechanical and an electrical stimulus in 30 pregnant women (pregnant group) scheduled for cesarean section and 30 healthy female volunteers (control group) matched for age. Pain was assessed by Visual Analogue Scale (VAS) on two different days after skin application of EMLA or placebo cream on the forearms. EMLA and placebo cream were randomly applied on the medial surface of both forearms for 30 min in a blind cross over manner and the subjects received a mechanical stimulus generated through a pressor palpator followed by an electrical stimulus generated through a nerve stimulator. RESULTS: Average VAS values from both trials did not differ between pregnant and control group exposed to the mechanical or electrical stimulus after EMLA application or after mechanical or electrical stimulus after placebo cream application.. CONCLUSIONS: Late pregnancy is not associated with increased sensitivity to local anesthetics (EMLA) applied to the skin, under our study conditions.