Erect lateral pelvimetry and the outcome of labor in Lagos.

The erect lateral radiograph pelvimetry measurements was related to the outcome of labor in 173 patients. The most common indication for pelvimetry was one previous caesarean section in 90 (52%) patients. Sixty-nine (39.9%) pelvimetry measurements were performed because of suspected cephalopelvic disproportion, while 20 (11.6%) were done because of breech presentation. In patients with a cephalic presentation at delivery, the mean +/- standard deviation (SD) obstetric conjugate for the 87 women who delivered vaginally (group 1) was 11.42 +/- 1.5 cm, while that of the 45 women who had emergency caesarean section (group 2) was 10.77 +/- 1.5 cm. The mean +/- SD anteroposterior outlet diameter for groups 1 and 2 were 12.24 +/- 1.9 cm and 11.84 +/- 1.7 cm respectively. Both differences were found to be statistically significant (p < 0.001 and p < 0.05 respectively). The mean +/- SD birthweight of the babies in groups 1 and 2 were 3.34 +/- 0.79 kg and 3.42 +/- 0.86 kg respectively. There was no statistically significant difference between the two groups (p < 0.05). The critical obstetric conjugate for safe vaginal delivery was 9.88 cm while the corresponding value for the anteroposterior pelvic outlet diameter was 10.24 cm.