(1109) Optimal second stage duration in nulliparas: why don’t we use morbidity to guide a cut-off?

Friday, February 10, 2023

3:30 PM – 5:00 PM

Objective: The 2010 Consortium on Safe Labor data suggests that approximately 50% of nulliparas with epidurals will deliver within the first hour of second stage. We investigated the cumulative risks of maternal and neonatal morbidity, and likelihood of spontaneous vaginal delivery (SVD) for every 30 minute duration of the second stage past 1 hour.

Study Design: Secondary analysis of a multicenter randomized trial in which nulliparas with term pregnancies and neuraxial analgesia were assigned at complete dilation to immediate or delayed (60 min) pushing. The co-primary outcomes were composite maternal (3rd/4th degree perineal lacerations, maternal fever, postpartum hemorrhage, transfusion, endomyometritis) and neonatal (death, birth injury, acidemia, respiratory distress, transient tachypnea, meconium aspiration, hypoxic-ischemic encephalopathy, hypoglycemia, hypothermia treatment, or suspected sepsis) morbidity. Secondary outcome was SVD. Multivariable logistic regression was used to determine the risks of outcomes for every 30 min interval past initial hour of second stage compared to all preceding time intervals (cumulative risk).

Results: Of 2404 patients in the trial, 1789 (74%) had a second stage >1 hour. The risk of maternal morbidity significantly increased with every additional 30 minutes when the second stage was longer than 90 min. The risk of neonatal morbidity increased with every additional 30 min added to the second stage after 120 min. Every 30 min extension of the second stage did not impact the likelihood of SVD until after 150 min when the chance of SVD was 26% lower than those with a shorter second stage.

Conclusion: Nulliparas with a second stage longer than 120 mins are at increased risk of maternal and neonatal morbidity with similar chances of SVD as those with a shorter second stage. Although these risks should be compared to the alternative risks of second stage cesarean, these data call for the definition of prolonged second stage to be revisited based on risk of morbidity.

Primary & Presenting Author(s)

Nandini Raghuraman, MD,MSc (she/her/hers)
Assistant Professor
Barnes Jewish Hospital, Washington University in St Louis
St. Louis, Missouri, United States

Coauthor(s)

CW
Candice Woolfolk, MPH, PhD
Research Statistician
Washington University in St.Louis
St. Louis, Missouri, United States
Sindhu K. Srinivas, MD, MSCE
Professor, Vice Chair for Quality and Safety, Physician Lead, Women's Health Service Line Penn Medicine
Perelman School of Medicine, University of Pennsylvania
Philadelphia, Pennsylvania, United States
Antonina I. Frolova, MD,PhD (she/her/hers)
Assistant Professor
Washington University School of Medicine
St. Louis, Missouri, United States
Lorie M. Harper, MD,MSCI (she/her/hers)
Associate Professor
University of Texas Dell Medical School
Austin, Texas, United States
Aaron B. Caughey, MD,MPH,PhD
Professor and Chair
Oregon Health and Science University
Portland, Oregon, United States
Alan T. Tita, MD, PhD
Professor
University of Alabama at Birmingham
Birmingham, Alabama, United States
Methodius G. Tuuli, MD, MPH, MBA
Chace-Joukowsky Professor and Chair
Women & Infants Hospital of Rhode Island, Warren Alpert Medical School of Brown University
East Greenwich, Rhode Island, United States
Alison G. Cahill, MD, MSCI
Professor
University of Texas at Austin, Dell Medical School
Austin, Texas, United States