Association between induction start time and labor duration in nulliparous women undergoing elective induction of labor

Francesca Lucia Facco, Obstetrics and Gynecology, University of Pittsburgh, Pittsburgh, United States.
Cora MacPherson, Epidemiology, George Washington University Biostatistics Center, ROCKVILLE, United States.
Uma Reddy, Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, United States.
Alan Tita, Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, United States.
Robert M. Silver, Obstetrics & Gynecology, University of Utah School of Medicine, Salt Lake City, United States.
Yasser El-Sayed, OB/Gyn, Stanford University, Stanford, United States.
Ronald Wapner, OB/GYN, Columbia University Medical Center, New York, United States.
Dwight J. Rouse, University of Alabama at Birmingham, Birmingham, United States.
George Saade, OB-GYN, EVMS, Norfolk, United States.
John M. Thorp
Suneet P. Chauhan, Maternal-Fetal Medicine, Delaware Center of Maternal-Fetal Medicine, Newark, United States.
Maged M. Costantine, Maternal-Fetal Medicine, Ohio State University Wexner Medical Center, Columbus, United States.
Edward Chien, OB GYN Specialist, Cleveland Clinic OB GYN and Women's Health Institute, Cleveland, United States.
Kent Heyborne, Obstetrics and Gynecology, Denver Health, Denver, United States.
Sindhu K. Srinivas, Obstetrics and Gynecology CRRWH, University of Pennsylvania, Philadelphia, United States.
Geeta K. Swamy, Obstetrics and Gynecology, Section of Maternal-Fetal Medicine, Duke University, Durham, United States.
William A. Grobman, Brown University, Providence, United States.

Document Type

Journal Article

Publication Date

2-27-2025

Journal

American journal of perinatology

DOI

10.1055/a-2547-4196

Abstract

OBJECTIVE: To examine the association between elective induction of labor (EIOL) start time and labor duration among nulliparous women Methods: The ARRIVE trial was a multi-center randomized controlled trial of induction of labor at 39 weeks 0 days to 39 weeks 4 days versus expectant management in low-risk nulliparous women. In this secondary analysis, we included participants randomized to the induction group who had an EIOL without spontaneous labor or rupture of membranes prior to the induction start. Start time of EIOL was categorized as: early AM (midnight to 5:59 AM), late AM (6 AM-11:59 AM), early PM (noon-5:59 PM), or late PM (6 PM-11:59 PM). The primary outcome was labor duration. Cesarean delivery rates by induction start time were also examined. Multivariable analysis was conducted controlling for age, body mass index, insurance status, and modified Bishop score on admission (< 5 or ≥5). RESULTS: Of 3,062 women randomized to EIOL, 2,197 were included in this analysis. EIOL occurred in the early AM in 13%, in late AM in 28%, in early PM in 13%, and in late PM in 45%. Participants induced in the late AM had the shortest mean labor durations (21.5 ±11.3 hours) and the highest frequency of delivery at < 24 hours (68%). In adjusted analyses, induction in the late AM (vs. grouped other time periods) remained significantly associated with shorter labor duration (-1.5 hrs, 95% CI -2.5, -0.4, p=0.006), and there was no interaction between Bishop score and time of EIOL. Cesarean delivery rates did not differ by start time. CONCLUSIONS: Induction of labor starting between 6AM and 11:59 AM was associated with shorter labor durations, independent of baseline maternal characteristics including cervical status on admission.

Department

Epidemiology

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