The pelvic outlet. A comparison between clinical evaluation and radiologic pelvimetry.

A random sample of 798 primiparas was screened with clinical evaluation and radiologic low-dose pelvimetry of the pelvic outlet. The purpose was to study the accuracy of clinical evaluation in comparison with X-ray pelvimetry and to determine whether clinical evaluation could reveal any other factor influencing labor. A significant agreement between clinical and X-ray pelvimetry was found, but the sensitivity of clinical evaluation was low and as many as half the patients with a contracted pelvis, according to pelvimetry, were not detected. Delivery outcomes in two matched groups with similar pelvic outlet measurements but different clinical evaluation did not differ, indicating that clinical evaluation did not detect any other factor not revealed by X-ray pelvimetry.