(162) The ARRIVE Trial: Impact of Elective Induction on Subsequent Pregnancy Occurrence and Mode of Delivery

Thursday, February 9, 2023

10:30 AM – 12:00 PM

Objective: Elective induction of labor (EIOL) is associated with a lower rate of cesarean delivery (CD) than expectant management (EM) in nulliparous people. However, impact on subsequent pregnancies is unknown. Our goal was to assess whether EIOL compared to EM at 39 weeks of gestation in nulliparas is associated with differences in the occurrence of a subsequent pregnancy and mode of delivery in the next pregnancy.

Study Design: This was a follow-up study of the ARRIVE trial, an RCT of EIOL vs EM among nulliparas at 39 weeks. Participants from one ARRIVE site who agreed to contact for future studies were invited to complete a survey about medical and obstetric events after ARRIVE. We compared the rate of subsequent pregnancy (yes/no) and among term, livebirth, singleton gestations, the mode of delivery in the next pregnancy by ARRIVE randomization group. Multivariable logistic regression adjusted for time since ARRIVE.

Results: 762 of 1,038 (73%) people responded on an average of 4.5 years (SD:1) after ARRIVE, responding and non-responding groups were similar in ARRIVE-recorded race/ethnicity, age >=35, obesity, insurance, smoking, randomization, and delivery mode. Of 754 people with data on subsequent pregnancies, 62% reported a subsequent pregnancy, similarly by ARRIVE randomization (EIOL 64%, EM 60%, p=0.4), and when adjusted for time since ARRIVE (figure). Of 412 participants with a term singleton next delivery, characteristics were similar by ARRIVE randomization (table). Cesarean delivery in the next pregnancy did not significantly differ by ARRIVE randomization (11% EIOL, 13% EM, p=0.6), nor when adjusted for time since ARRIVE (figure).

Conclusion: In this follow up study, there was no difference in subsequent term delivery rates among those who were randomized to EIOL or EM at 39 weeks. Those who were randomized to EIOL had a higher frequency of subsequent vaginal birth, but this difference did not reach statistical significance.

Primary & Presenting Author(s)

Dana R. Canfield, MD
Maternal Fetal Medicine Fellow
University of California, San Diego
La Jolla, California, United States

Coauthor(s)

AA
Amanda A. Allshouse, MS
Perinatal Biostatistician
University of Utah
Salt Lake City, Utah, United States
JS
Jessica Smith, MD
University of Utah
Salt Lake City, Utah, United States
Torri D. Metz, MD, MS (she/her/hers)
Associate Professor
University of Utah Health
Salt Lake City, Utah, United States
William A. Grobman, MD, MBA
Vice Chair, Clinical Operations, Maternal Fetal Medicine
The Ohio State University
Columbus, Ohio, United States
RS
Robert M. Silver, MD
University of Utah Health
Salt Lake City, Utah, United States