Why are our sister's exploding?

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Am J Obstet Gynecol. 2008 May

1. [Epub ahead of print] Higher maximum doses

of oxytocin are associated with an unacceptably high risk for uterine

rupture in patients attempting vaginal birth after cesarean delivery.

Cahill AG, Waterman BM, Stamilio DM, Odibo AO, Allsworth JE, Evanoff B,

Macones GA. Department of Obstetrics and Gynecology, Washington University

School of Medicine, St. Louis, MO.

OBJECTIVE: The objective of the study was to more precisely estimate the

effect of maximum oxytocin dose on uterine rupture risk in patients

attempting vaginal birth after cesarean (VBAC) by considering timing and

duration of therapy.

STUDY DESIGN: A nested case-control study was conducted within a

multicenter, retrospective cohort study of more than 25,000 women with at

least 1 prior cesarean delivery, comparing cases of uterine rupture with

controls (no rupture) while attempting VBAC. Time-to-event analyses were

performed to examine the effect of maximum oxytocin dose on the risk of

uterine rupture considering therapy duration, while adjusting for

confounders.

RESULTS: Within the nested case-control study of 804 patients, 272 were

exposed to oxytocin: 62 cases of uterine rupture and 210 controls. Maximum

oxytocin ranges above 20 mU/min increased the risk of uterine rupture 4-fold

or greater (21-30 mU/min: hazard ratio

---

3.92, 95% confidence interval

[CI], 1.06 to 14.52; 31-40 mU/min: HR 4.57, 95% CI, 1.00 to 20.82).

CONCLUSION: These findings support a maximum oxytocin dose of 20 mU/min in

VBAC trials to avoid an unacceptably high risk of uterine rupture.

PMID: 18455132 [PubMed - as supplied by publisher]