[The influence of the menstrual cycle on acute and persistent pain after laparoscopic cholecystectomy]. / A influência do ciclo menstrual na dor aguda e persistente após colecistectomia laparoscópica.

BACKGROUND AND OBJECTIVES: Fluctuations of female sex hormones during menstrual cycle influence pain perception. Endogenous pain inhibition is impaired in follicular phase of menstrual cycle. We tested the primary hypothesis that the women having surgery during their follicular phase have more acute pain and require higher opioids than those in the luteal phase, and secondarily we tested that women who have surgery during their follicular phase have more incisional pain at 3 month postoperatively. METHODS: 127 adult females having laparoscopic cholecystectomy were randomized to have surgery during the luteal or follicular phase of their menstrual cycle. Standardized anesthesia and pain management regimen was given to all patients. Pain and analgesic consumption were evaluated in post-anesthesia care unit and every 4h in the first 24h. Adverse effects were questioned every 4h. Time to oral intake and ambulation were recorded. Post-surgical pain, hospital anxiety, depression scale, SF-12 questionnaire were evaluated at 1 and 3 month visits. RESULTS: There was no difference in acute pain scores and analgesic consumption through the 24h period, Visual Analog Scale at 24h was 1.5±1.5cm for follicular group 1.4±1.7cm for luteal group (p=0.57). Persistent postoperative pain was significantly more common one and at three month, with an incidence was 33% and 32% in the patients at follicular phase versus 16% and 12% at luteal phase, respectively. The Visual Analog Scale at one and at three month was 1.6±0.7cm and 1.8±0.8cm for follicular group and 2.7±1.3cm and 2.9±1.7cm in the luteal group (p=0.02), respectively. There were no significant differences between the groups with respect to anxiety and depression, SF-12 scores at either time. Nausea was more common in follicular-phase group (p=0.01) and oral feeding time was shorter in follicular phase (5.9±0.9h) than in luteal phase (6.8±1.9h, p=0.02). CONCLUSIONS: Although persistent postoperative pain was significantly more common one and three months after surgery the magnitude of the pain was low. Our results do not support scheduling operations to target particular phases of the menstrual cycle.