How long is too long: Does a prolonged second stage of labor in nulliparous women affect maternal and neonatal outcomes?
OBJECTIVE
The purpose of this study was to examine maternal and neonatal outcomes in relation to lengthening intervals of the second stage of labor.


METHODS
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).


CONCLUSIONS
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.
Department of Obstetrics, Gynaecology and Reproductive Services, University of California, San Francisco 94143, USA. yvecheng@hotmail.com
Yvonne W
YW
Cheng
Linda M
LM
Hopkins
Aaron B
AB
Caughey
D000704:Analysis of Variance; D002585:Cesarean Section / Q000706:statistics & numerical data; D002821:Chorioamnionitis / Q000453:epidemiology; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D006801:Humans; D007748:Labor Stage, Second; D022125:Lacerations / Q000453:epidemiology; D016015:Logistic Models; D008423:Maternal Age; D016017:Odds Ratio; D010298:Parity; D010502:Perineum / Q000293:injuries; D006473:Postpartum Hemorrhage / Q000453:epidemiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D018566:Pregnancy, High-Risk; D013997:Time Factors