How long is too long: Does a prolonged second stage of labor in nulliparous women affect maternal and neonatal outcomes?

Am J Obstet Gynecol. 2004 Sep;191(3):933-8. doi: 10.1016/j.ajog.2004.05.044.


Objective: The purpose of this study was to examine maternal and neonatal outcomes in relation to lengthening intervals of the second stage of labor.

Study design: This is a retrospective cohort study of 15,759 nulliparous, term, cephalic, singleton births at the University of California, San Francisco, between 1976 and 2001. The second stage of labor was divided into 1-hour intervals. Maternal and neonatal outcomes were compared with the use of chi-squared and Student t tests, and a probability value of < or =.05 was used to indicate statistical significance. Potential confounders were controlled for with multivariate logistic regression.

Results: Increasing rates of cesarean delivery, operative vaginal delivery, and perineal trauma were associated with the second stage beyond the first hour. In multivariate analysis, the >4-hour interval group had higher rates of cesarean delivery (odds ratio, 5.65; P < .001), operative vaginal deliveries (odds ratio, 2.83; P < .001), 3rd- or 4th-degree perineal lacerations (odds ratio, 1.33; P = .009), and chorioamnionitis (odds ratio, 1.79; P < .001). There were no differences in neonatal acid-base status associated with length of second stage. However, there were fewer neonates with a 5-minute Apgar score of <7 (odds ratio, 0.45; P = .01).

Conclusion: Although the length of the second stage of labor is not associated with poor neonatal outcome, a prolonged second stage is associated with increased maternal morbidity and operative delivery rates.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analysis of Variance
  • Cesarean Section / statistics & numerical data
  • Chorioamnionitis / epidemiology
  • Delivery, Obstetric / methods
  • Female
  • Humans
  • Labor Stage, Second*
  • Lacerations / epidemiology
  • Logistic Models
  • Maternal Age
  • Odds Ratio
  • Parity*
  • Perineum / injuries
  • Postpartum Hemorrhage / epidemiology
  • Pregnancy
  • Pregnancy Outcome*
  • Pregnancy, High-Risk
  • Time Factors