Labor outcomes with increasing number of prior vaginal births after cesarean delivery.
OBJECTIVE
To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs.


METHODS
From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery.


RESULTS
Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter.


CONCLUSIONS
Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy.


METHODS
II.
Mercer
Brian M
BM
Department of Obstetrics and Gynecology at Case Western Reserve University-MetroHealth Medical Center, Cleveland, Ohio 44109-1989, USA.
Gilbert
Sharon
S
Landon
Mark B
MB
Spong
Catherine Y
CY
Leveno
Kenneth J
KJ
Rouse
Dwight J
DJ
Varner
Michael W
MW
Moawad
Atef H
AH
Simhan
Hyagriv N
HN
Harper
Margaret
M
Wapner
Ronald J
RJ
Sorokin
Yoram
Y
Miodovnik
Menachem
M
Carpenter
Marshall
M
Peaceman
Alan
A
O'Sullivan
Mary J
MJ
Sibai
Baha M
BM
Langer
Oded
O
Thorp
John M
JM
Ramin
Susan M
SM
D000328:Adult; D001034:Apgar Score; D005260:Female; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D008428:Maternal Mortality; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012307:Risk Factors; D014219:Trial of Labor; D014597:Uterine Rupture / Q000453:epidemiology*; D016064:Vaginal Birth after Cesarean / Q000009:adverse effects* / Q000706:statistics & numerical data*