Abstract
Objective The objective of this study was to estimate epidural timing's impact on fetal station
during active labor.
Study Design This secondary analysis of a single-institution prospective cohort study included
all term singleton pregnancies, stratified by parity. Those with early epidurals (placed
at <6 cm) were compared with those with late epidurals (placed at ≥6 cm). The primary
outcome was median fetal station from 6 to 10 cm. Secondary outcomes included rate
of prolonged first or second stage of labor (>95%). Multivariable logistic regression
adjusted for labor type.
Results Among 7,647 women, 3,434 were nulliparous (2,983 with early epidurals and 451 with
late epidurals) and 4,213 multiparous (3,141 with early epidurals and 1,072 with late
epidurals). Interquartile ranges (IQRs) suggested fetal station at 6 cm was likely
lower among those with early epidurals (nulliparous: median head station −1 [IQR:
−1 to 0] for early epidural vs. −1 [IQR: −2 to 0] for late epidural, p < 0.01; multiparous: −1 (IQR: −2 to 0] for early epidural vs. −1 [IQR: −3 to −1]
for late epidural, p < 0.01). Early epidurals were not associated with increased risk of prolonged first
stage, but among nulliparous were associated with decreased risk of prolonged second
stage (adjusted odds ratio: 0.66 [95% confidence interval: 0.44–0.99]).
Conclusion Early epidurals were associated with lower fetal station in active labor but not
prolonged first stage.
Keywords
epidural anesthesia - fetal station - modern labor curve - active labor
