Why is colonoscopy more difficult in women?

Background: In our experience colonoscopy in women is more difficult than in men. A retrospective review of 2194 colonoscopies performed by a single experienced endoscopist (CBW) showed that 31% of examinations in women were considered technically difficult compared with 16% in men. Methods: To investigate a possible anatomic basis for this finding, normal barium enema series from 183 female and 162 male patients were identified. From these barium enemas, measurements of colonic length and mobility were independently taken by two physicians who were unaware of each patient's gender. Results: Total colonic length was greater in women (median, 155 cm) compared to men (median, 145 cm), p=0.005, despite women's smaller stature (p<0.0001). Although there were no significant differences in rectum plus sigmoid, descending, or ascending plus cecum segmental lengths, women had longer transverse colons (female median length, 48 cm; male median length, 40 cm), p<0.0001. There were no differences in mobility of the descending colon and transverse colon between the sexes, but the transverse colon reached the true pelvis more often in women (62%) than in men (26%), p<0.001. Conclusions: Colonoscopy appears to be a technically more dificult procedure in women. The reason for this may be due in part to an inherently longer colon.