The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery.
OBJECTIVE
The purpose of this study was to determine which factors influence the likelihood of successful trial of labor (TOL) after 1 previous cesarean delivery (CD).


METHODS
We performed a multicenter 4-year prospective observational study (1999-2002) of all women with previous CD undergoing TOL. Women with term singleton pregnancies with 1 previous low transverse CD or unknown incision were included for analysis.


RESULTS
Fourteen thousand five hundred twenty-nine women underwent TOL, with 10,690 (73.6%) achieving successful VBAC. Women with previous vaginal birth had an 86.6% success rate compared with 60.9% in women without such a history (odds ratio [OR] 4.2; 95% CI 3.8-4.5; P < .001). TOL success rates were affected by previous indication for CD, need for induction or augmentation, cervical dilation on admission, birth weight, race, and maternal body mass index. Multivariate logistic regression analysis identified as predictive of TOL success: previous vaginal delivery (OR 3.9; 95% CI 3.6-4.3), previous indication not being dystocia (CPD/FTP) (OR 1.7; 95% CI 1.5-1.8), spontaneous labor (OR 1.6; 95% CI 1.5-1.8), birth weight <4000 g (OR 2.0; 95% CI 1.8-2.3), and Caucasian race (OR 1.8, 95% CI 1.6-1.9) (all P < .001). The overall TOL success rate in obese women (BMI > or = 30) was lower (68.4%) than in nonobese women (79.6%) (P < .001), and when combined with induction and lack of previous vaginal delivery, successful VBAC occurred in only 44.2% of cases.


CONCLUSIONS
Previous vaginal delivery including previous VBAC is the greatest predictor for successful TOL. Previous indication as dystocia, need for labor induction, or a maternal BMI > or = 30 significantly lowers success rates.
Landon
Mark B
MB
Department of Obstetrics and Gynecology at The Ohio State University College of Medicine and Public Health, Columbus, OH 43210-1228, USA. landon.l@osu.edu
Leindecker
Sharon
S
Spong
Catherine Y
CY
Hauth
John C
JC
Bloom
Steven
S
Varner
Michael W
MW
Moawad
Atef H
AH
Caritis
Steve N
SN
Harper
Margaret
M
Wapner
Ronald J
RJ
Sorokin
Yoram
Y
Miodovnik
Menachem
M
Carpenter
Marshall
M
Peaceman
Alan M
AM
O'Sullivan
Mary Jo
MJ
Sibai
Baha M
BM
Langer
Oded
O
Thorp
John M
JM
Ramin
Susan M
SM
Mercer
Brian M
BM
Gabbe
Steven G
SG
D000328:Adult; D017604:Cesarean Section, Repeat / Q000706:statistics & numerical data*; D004420:Dystocia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007751:Labor, Induced / Q000706:statistics & numerical data; D016015:Logistic Models; D016017:Odds Ratio; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012307:Risk Factors; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data*