Second-stage labor duration in nulliparous women: relationship to maternal and perinatal outcomes.
OBJECTIVE
The purpose of this study was to assess maternal and perinatal outcomes as a function of second-stage labor duration.


METHODS
We assessed outcomes in nulliparous laboring women who were enrolled in a trial of fetal pulse oximetry.


RESULTS
Of 5341 participants, 4126 women reached the second stage of labor. As the duration of the second stage increased, spontaneous vaginal delivery rates declined, from 85% when the duration was <1 hour to 9% when it was > or =5 hours. Adverse maternal outcomes that were associated significantly with the duration of the second stage of labor included chorioamnionitis (overall rate, 3.9%), third- or fourth-degree perineal laceration (overall rate, 8.7%), and uterine atony (overall rate, 3.9%). Odds ratios for each additional hour of the second stage of labor ranged from 1.3-1.8. Among individual adverse neonatal outcomes, only admission to a neonatal intensive care unit was associated significantly with second stage duration (odds ratio, 1.4).


CONCLUSIONS
The second stage of labor does not need to be terminated for duration alone.
Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, AL, USA.
Dwight J
DJ
Rouse
Steven J
SJ
Weiner
Steven L
SL
Bloom
Michael W
MW
Varner
Catherine Y
CY
Spong
Susan M
SM
Ramin
Steve N
SN
Caritis
Alan M
AM
Peaceman
Yoram
Y
Sorokin
Anthony
A
Sciscione
Marshall W
MW
Carpenter
Brian M
BM
Mercer
John M
JM
Thorp
Fergal D
FD
Malone
Margaret
M
Harper
Jay D
JD
Iams
Garland D
GD
Anderson
D000328:Adult; D001720:Birth Injuries / Q000453:epidemiology; D001917:Brachial Plexus / Q000293:injuries; D005260:Female; D006801:Humans; D007363:Intensive Care Units, Neonatal; D007748:Labor Stage, Second; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D013997:Time Factors