Amer J Perinatol
DOI: 10.1055/s-0037-1617457
SMFM Fellowship Series Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Epidurals and the Modern Labor Curve: How Epidural Timing Impacts Fetal Station during Active Labor

Adam K. Lewkowitz1, Methodius G. Tuuli1, Molly J. Stout1, Candice Woolfolk1, Kimberly Roehl1, George A. Macones1, Alison G. Cahill1
  • 1Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, Missouri
Further Information

Publication History

29 April 2017

29 November 2017

Publication Date:
29 December 2017 (eFirst)


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.


This abstract was presented as a poster presentation at the 37th Annual SMFM Pregnancy Meeting, hosted by the Society for Maternal-Fetal Medicine in Las Vegas, NV from January 23–28, 2017, under final program ID number 457.


This project was supported in part by a Robert Wood Johnson Foundation Physician Faculty Scholar Award (A.G.C.).