Related Experiment Video
Updated: Jun 6, 2026

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Contemporary patterns of spontaneous labor with normal neonatal outcomes
Jun Zhang1, Helain J Landy, D Ware Branch
1From the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Georgetown University Hospital, MedStar Health, Washington, DC; Intermountain HealthCare and University of Utah, Salt Lake City, Utah; Baystate Medical Center, Springfield, Massachusetts; Maimonides Medical Center, Brooklyn, New York; Cedars-Sinai Medical Center, Los Angeles, California; Summa Health System, Akron City Hospital, Akron, Ohio; University of Texas Health Science Center at Houston, Houston, Texas; MetroHealth Medical Center, Cleveland, Ohio; University of Miami, Miami, Florida; University of Illinois at Chicago, Chicago, Illinois; Christiana Care Health System, Wilmington, Delaware; Indiana University-Clarian Health, Indianapolis, Indiana; and The EMMES Corporation, Rockville, Maryland.
Objective:
To use contemporary labor data to examine the labor patterns in a large, modern obstetric population in the United States.
Methods:
Data were from the Consortium on Safe Labor, a multicenter retrospective study that abstracted detailed labor and delivery information from electronic medical records in 19 hospitals across the United States. A total of 62,415 parturients were selected who had a singleton term gestation, spontaneous onset of labor, vertex presentation, vaginal delivery, and a normal perinatal outcome. A repeated-measures analysis was used to construct average labor curves by parity. An interval-censored regression was used to estimate duration of labor, stratified by cervical dilation at admission and centimeter by centimeter.
Results:
Labor may take more than 6 hours to progress from 4 to 5 cm and more than 3 hours to progress from 5 to 6 cm of dilation. Nulliparous and multiparous women appeared to progress at a similar pace before 6 cm. However, after 6 cm, labor accelerated much faster in multiparous than in nulliparous women. The 95 percentiles of the second stage of labor in nulliparous women with and without epidural analgesia were 3.6 and 2.8 hours, respectively. A partogram for nulliparous women is proposed.
Conclusion:
In a large, contemporary population, the rate of cervical dilation accelerated after 6 cm, and progress from 4 cm to 6 cm was far slower than previously described. Allowing labor to continue for a longer period before 6 cm of cervical dilation may reduce the rate of intrapartum and subsequent repeat cesarean deliveries in the United States.
