Carbon dioxide versus normal saline in outpatient hysteroscopy.

BACKGROUND The aim of this prospective randomized study was to measure patients' discomfort after hysteroscopy with CO(2) or normal saline. METHODS A total of 415 patients was randomized to two groups according to distension medium (CO(2), n = 201; normal saline, n = 214). The nature of randomization was to alternate distension media on a weekly basis. After hysteroscopy, women were asked to rate the pain experienced on a 100-mm visual analogue scale (0 = no pain; 100 = worst imaginable pain). Pain scores were expressed as mean +/- SD (0-40 = minimal; 41-70 = moderate; 71-100 = severe). Data were analysed using Student's t-test. RESULTS Irrespective of the distension medium used, pelvic discomfort was worse in nulliparous women (pain score 39.0 +/- 26.5) than in multiparous women (30.4 +/- 25.9) (P < 0.05), especially if they were premenopausal. For all patients and both distension media, pelvic discomfort was generally minimal but higher in patients who had undergone hysteroscopy with normal saline (P < 0.05). CONCLUSIONS CO(2) and normal saline were comparable with regard to patient discomfort, but in terms of the high frequency of abnormal uterine bleeding, normal saline may be the most appropriate distension medium for outpatient hysteroscopy.