Poster Session 2
Jourdan E. Triebwasser, MA, MD (she/her/hers)
Clinical Associate Professor
University of Michigan
Ann Arbor, Michigan, United States
Evan J. Keil, MD
Resident in Obstetrics and Gynecology
University of Michigan
Ann Arbor, Michigan, United States
Rebecca Wardrop, PhD
University of Michigan
Ann Arbor, Michigan, United States
Xilin Chen, MPH
University of Michigan
Ann Arbor, Michigan, United States
Rebecca F. Hamm, MD, MSCE (she/her/hers)
Assistant Professor
University of Pennsylvania Perelman School of Medicine
Philadelphia, Pennsylvania, United States
Lisa Kane Low, CNM, PhD (she/her/hers)
University of Michigan
Ann Arbor, Michigan, United States
Abigail Ramseyer, DO
University of Michigan Health-Sparrow
Lansing, Michigan, United States
Molly J. Stout, MD, MSCI (she/her/hers)
Division Chief for Maternal Fetal Medicine, Associate Professor of Obstetrics and Gynecology
University of Michigan Medical Center
Ann Arbor, Michigan, United States
Michelle Moniz, MD, MSc (she/her/hers)
Associate Professor
University of Michigan
Ann Arbor, Michigan, United States
To evaluate the association of prolonged induction of labor (IOL) on severe maternal morbidity (SMM) and severe neonatal morbidity (SNM) among nulliparous, term, singleton, vertex (NTSV) births.
Study Design:
Retrospective cohort study across 70 hospitals using clinically abstracted data from the Obstetrics Initiative, a quality improvement initiative supported by Blue Cross Blue Shield of Michigan and Blue Care Network. We included NTSV IOL from 01/2022 to 12/2023. Prolonged IOL was defined as duration > 75th percentile for the cohort. Primary outcomes were SMM (Centers for Disease Control criteria) and SNM (unexpected complications in term newborns, PC-06). Secondary outcomes were postpartum hemorrhage (PPH, blood loss > 1000 mL) and obstetric infection (chorioamnionitis or endometritis). A 1-to-1 propensity score-matched analysis was performed between those with and without prolonged IOL within a hospital using greedy nearest neighbor matching. Adjusted odds ratios (aOR) were calculated adjusting for hospital characteristics (teaching status, higher level neonatal care) to account for hospital-level clustering. Results were stratified by mode of delivery.
Results:
Among 29,340 NTSV inductions, the 75th percentile for IOL length was 31 h 47 min. In unadjusted analyses, prolonged IOL was associated with SMM (4.5% vs. 3.0%, p < 0.001), SNM (6.1% vs. 4.0%, p < 0.001), cesarean (50% vs. 28%, p < 0.001), PPH (19% vs. 10%, p < 0.001), and obstetric infection (10% vs. 5.2%, p < 0.001). After propensity score matching (Table), prolonged IOL was associated with SMM (aOR 1.43, 95% CI 1.06-1.92) and SNM (aOR 1.37, 95% CI 1.07-1.75) among vaginal, but not cesarean births (Figure). Prolonged IOL was associated with increased risk of PPH for vaginal (aOR 1.70, 95% CI 1.40-2.07) and cesarean births (aOR 1.30, 95% CI 1.13-1.50). Similarly, prolonged IOL was associated with obstetric infection for vaginal (aOR 2.07, 95% CI 1.68-2.54) and cesarean births (aOR 1.48, 95% CI 1.20-1.81).
Conclusion:
Prolonged IOL is associated with maternal and neonatal morbidity, particularly for vaginal births.
