Fluctuations of female sex hormones during the menstrual cycle influence pain perception. Endogenous pain is pronounced in the follicular phase of the menstrual cycle. The investigators tested the primary hypothesis that the women having surgery during their follicular phase have more acute pain and require more opioids than those in the luteal phase, and secondarily the investigators tested that women who have surgery during their follicular phase have more incisional pain at 3 month postoperatively.

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 PACU and every four hours in first 24 hours. Adverse effects were also questioned every four hours. Time to oral intake and ambulation were recorded. Post-surgical pain, hospital anxiety and depression scale, and SF-12 questionnaire were also evaluated at 1- and 3-month visits.

Inclusion Criteria:

• Women with a negative urine pregnancy test

Exclusion Criteria:

• Patients with pre-existing pain syndromes
• Patients using routinely using opioids
• Patients using hormone preparations in the last 6 months
• Patients with hysterectomy
• Patients breastfeeding in the previous 6 months
• Patients with body mass index >35 kg/m2