Does a maximum dose of oxytocin affect risk for uterine rupture in candidates for vaginal birth after cesarean delivery?
OBJECTIVE
The purpose of this study was to determine whether the maximum dose of oxytocin impacts the risk of uterine rupture in women who attempt vaginal birth after cesarean delivery (VBAC).


METHODS
We conducted a retrospective, multicenter cohort study of women with a history of cesarean delivery. We compared uterine rupture rates between VBAC candidates that did and did not receive oxytocin, analyzing the association between maximum dose of oxytocin and uterine rupture. Bivariate and multivariate analyses were performed.


RESULTS
Of the 13,523 patients who elected a VBAC trial, 128 women experienced a uterine rupture; 80 of these ruptures were in women who received oxytocin (62.5%). There was evidence of "dose response" for maximum oxytocin amount and uterine rupture, with a uterine rupture rate of 2.07% (adjusted odds ratio, 2.98; 95% CI 1.51-5.90) at the highest dosages.


CONCLUSIONS
In VBAC attempts, a dose-response relationship of maximum oxytocin and uterine rupture exists. These results provide evidence for vigilance when higher doses of oxytocin are given to patients who attempt VBAC.
Cahill
Alison G
AG
Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO 63105, USA. cahilla@wustl.edu
Stamilio
David M
DM
Odibo
Anthony O
AO
Peipert
Jeffrey F
JF
Stevens
Erika J
EJ
Macones
George A
GA
D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D010120:Oxytocics / Q000008:administration & dosage* / Q000009:adverse effects; D010121:Oxytocin / Q000008:administration & dosage* / Q000009:adverse effects; D011247:Pregnancy; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment; D014597:Uterine Rupture / Q000139:chemically induced / Q000453:epidemiology*; D016064:Vaginal Birth after Cesarean
D010120:Oxytocics; D010121:Oxytocin