Previous preterm cesarean delivery and risk of subsequent uterine rupture.
OBJECTIVE
To determine if women with a history of a previous preterm cesarean delivery experienced an increased risk of subsequent uterine rupture compared with women who had a previous nonclassic term cesarean delivery.


METHODS
A prospective observational study was performed in singleton gestations that had a previous nonclassic cesarean delivery from 1999 to 2002. Women with a history of a previous preterm cesarean delivery were compared with women who had a previous term cesarean delivery. Women who had both a preterm and term cesarean delivery were included in the preterm group.


RESULTS
A prior preterm cesarean delivery was significantly associated with an increased risk of subsequent uterine rupture (0.58% compared with 0.28%, P<.001). When women who had a subsequent elective cesarean delivery were removed (remaining n=26,454) women with a previous preterm cesarean delivery were still significantly more likely to sustain a uterine rupture (0.79% compared with 0.46%, P=.001). However, when only women who had a subsequent trial of labor were included, there was still an absolute increased risk of uterine rupture, but it was not statistically significant (1.00% compared with 0.68%, P=.081). In a multivariable analysis controlling for confounding variables (oxytocin use, two or more previous cesarean deliveries, a cesarean delivery within the past 2 years, and preterm delivery in the current pregnancy), patients with a previous preterm cesarean delivery remained at an increased risk of subsequent uterine rupture (P=.043, odds ratio 1.6, 95% confidence interval 1.01-2.50) compared with women with previous term cesarean delivery.


CONCLUSIONS
Women who have had a previous preterm cesarean delivery are at a minimally increased risk for uterine rupture in a subsequent pregnancy when compared with women who have had previous term cesarean deliveries.
Sciscione
Anthony C
AC
Department of Obstetrics and Gynecology at Christiana Care Health System, Newark, Delaware 19713, USA. asciscione@christianacare.org
Landon
Mark B
MB
Leveno
Kenneth J
KJ
Spong
Catherine Y
CY
Macpherson
Cora
C
Varner
Michael W
MW
Rouse
Dwight J
DJ
Moawad
Atef H
AH
Caritis
Steve N
SN
Harper
Margaret
M
Sorokin
Yoram
Y
Miodovnik
Menachem
M
Marshall
Carpenter
C
Peaceman
Alan M
AM
O'Sullivan
Mary J
MJ
Sibai
Baha M
BM
Langer
Oded
O
Thorp
John M
JM
Ramin
Susan M
SM
Mercer
Brian M
BM
D000328:Adult; D016022:Case-Control Studies; D002585:Cesarean Section / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016017:Odds Ratio; D011247:Pregnancy; D047928:Premature Birth; D011446:Prospective Studies; D014597:Uterine Rupture / Q000209:etiology*