Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Randomized Controlled Trial
. 2025 Oct;42(14):1864-1870.
doi: 10.1055/a-2547-4196. Epub 2025 Feb 27.

Association between Induction Start Time and Labor Duration in Nulliparous Women Undergoing Elective Induction of Labor

Francesca L Facco  1 , Cora MacPherson  2 , Uma M Reddy  3 , Alan T N Tita  4 , Robert M Silver  5 , Yasser Y El-Sayed  6 , Ronald J Wapner  7 , Dwight J Rouse  8 , George R Saade  9 , John M Thorp Jr  10 , Suneet P Chauhan  11 , Maged M Costantine  12 , Edward K Chien  13 , Kent D Heyborne  14 , Sindhu K Srinivas  15 , Geeta K Swamy  16 , William A Grobman  17 ; Eunice Kennedy Shriver National Institute of Child Health Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network
Affiliations
Randomized Controlled Trial

Association between Induction Start Time and Labor Duration in Nulliparous Women Undergoing Elective Induction of Labor

Francesca L Facco et al. Am J Perinatol. 2025 Oct.

Abstract

This study aimed to examine the association between elective induction of labor (EIOL) start time and labor duration among nulliparous women.The ARRIVE trial was a multicenter randomized controlled trial of induction of labor at 390/7 to 394/7 weeks 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. The start time of EIOL was categorized as: early a.m. (midnight to 5:59 a.m.), late AM (6 AM-11:59 a.m.), early p.m. (noon-5:59 p.m.), or late p.m. (6 p.m.-11:59 p.m.). 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).Of 3,062 women randomized to EIOL, 2,197 were included in this analysis. EIOL occurred in the early a.m. in 13%, in late a.m. in 28%, in early p.m. in 13%, and in late p.m. in 45%. Participants induced in the late a.m. 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 a.m. (vs. grouped other time periods) remained significantly associated with shorter labor duration (-1.5 hours; confidence interval: -2.5 and -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.Induction of labor starting between 6 a.m. and 11:59 a.m. was associated with shorter labor durations, independent of baseline maternal characteristics including cervical status on admission. · Women were associated with shorter labor durations. · Cesarean delivery rates did not differ by EIOL start time.. · Differences in labor management by time of day may in part explain these findings..

PubMed Disclaimer

Conflict of interest statement

G.K.S. is associated with Pfizer, Moderna, Dynavax, GlaxoSmithKline DSMB/Advisory board, while E.K.C is associated with Novo Nordisk DSMB/consulting fees.

Figures

Fig. 1
Fig. 1
Kaplan–Meier survival curves for labor duration by induction time category (p = 0.002).
See this image and copyright information in PMC

References

    1. Moore TR. Patterns of human uterine contractions: implications for clinical practice. Semin Perinatol. Feb 1995;19(1):64–72. - PubMed
    1. Moore TR, Iams JD, Creasy RK, Burau KD, Davidson AL. Diurnal and gestational patterns of uterine activity in normal human pregnancy. The Uterine Activity in Pregnancy Working Group. Obstet Gynecol. Apr 1994;83(4):517–23. - PubMed
    1. Bakker JJ, van der Goes BY, Pel M, Mol BW, van der Post JA. Morning versus evening induction of labour for improving outcomes. Cochrane Database Syst Rev. Feb 28 2013;(2):CD007707. doi: 10.1002/14651858.CD007707.pub2 - DOI - PMC - PubMed
    1. Grobman WA, Rice MM, Reddy UM, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. N Engl J Med. Aug 9 2018;379(6):513–523. doi: 10.1056/NEJMoa1800566 - DOI - PMC - PubMed
    1. Kawakita T, Saeed H, Huang JC. An Externally Validated Model to Predict Prolonged Induction of Labor with an Unfavorable Cervix. Am J Perinatol. Nov 23 2023;doi: 10.1055/a-2195-6063 - DOI - PubMed

Publication types