Station and cervical dilation at epidural placement in predicting cesarean risk

To compare station and cervical dilation at the time of epidural placement for predicting cesarean delivery risk.

This prospective cohort study included 275 women in labor with live, singleton fetuses at term in vertex presentations. We excluded women with preeclampsia or previous cesarean deliveries. A multiple logistic regression model evaluated demographic and labor-related variables' associations with cesarean risk.

Fifty-nine of the 275 patients receiving epidural analgesia (21.5%) were delivered by cesarean, whereas 216 (78.5%) delivered vaginally. Variables that proved to be statistically significant in increasing the likelihood of cesarean were station at time of epidural placement (odds ratio [OR] 5.3; 95% confidence interval [CI] 2.6, 11.0; P < .001) and nulliparity (OR 3.8, 95% CI 1.8, 8.0; P < .001). Cervical dilation at the time of epidural placement was not a statistically significant predictor (OR 1.2, 95% CI 0.9, 1.6; P = .26). Cesareans were performed in 43 of 129 women (33.3%) who received epidurals with the vertex at a -1 station or higher, whereas only 16 of 146 women (11.0%) had cesareans if placement of the epidural was done after the vertex had reached at least a zero station.

Station at the time of epidural placement was more accurate predicting cesarean risk than cervical dilation. Placement of the epidural after the fetal vertex has become engaged in the pelvis (at least a zero station) resulted in a substantially lower cesarean risk.