Roentgenographic pelvimetry in single vertex pregnancies

Of the 4,529 women delivered of infants at The Johns Hopkins Hospital during 1976 and 1977, 212 (5%) had roentgenographic pelvimetry. An analysis of a subgroup of 142 single vertex pregnancies with radiographic pelvimetry during this two-year period is presented. The cesarean section rate was 40% among patients selected for roentgenographic pelvimetry whose pelvis was found to be adequate. Vaginal delivery in women with a pelvis radiographically shown to be small was accomplished in 27% of patients with failure to progress in labor and in 22% of the patients with a fetus in the floating vertex presentation. Patients with a small pelvis who delivered vaginally had significantly smaller infants than those delivered by cesarean section (2,785 ± 399 gm vs 3,146 ± 433 gm). The only significant difference in pelvic measurements between these two groups occurred in the AP diameter of the inlet (11.5 ± 1.1 cm vs 10.5 ± 1.0 cm). Roentgenographic pelvimetry of single vertex pregnancies as evaluated in this study appears to have limited clinical usefulness.