Interdelivery interval and risk of symptomatic uterine rupture

Objective: To relate interdelivery interval to risk of uterine rupture duri ng a trial of labor after prior cesarean delivery. Methods: We reviewed the medical records of all women who had a trial of la bor after cesarean delivery over 12 years (July 1984 to June 1996). Analysi s was limited to women with only one prior cesarean delivery and no prior v aginal deliveries who delivered term singletons and whose medical records i ncluded the month and year of the prior delivery. The time in months betwee n the prior cesarean delivery and the index trial of labor was calculated, and the women were divided accordingly to permit comparison with respect to symptomatic uterine rupture. Results: Two thousand four hundred nine women had trials of labor after one prior cesarean delivery and had complete data from the medical records. Th ere were 29 uterine ruptures (1.2%) in the population. For interdelivery in tervals up to 18 months, the uterine rupture rate was 2.25% (seven of 311) compared with 1.05% (22 of 2098) with intervals of 19 months or longer (P = .07). Multiple logistic regression was used to assess the risk of uterine rupture according to interdelivery interval while controlling for maternal age, public assistance, length of labor, gestational age at least 41 weeks, and oxytocin use. Women with interdelivery intervals of up to 18 months we re three times as likely (95% confidence interval, 1.2, 7.2) to have sympto matic uterine rupture. Conclusion: Interdelivery intervals of up to 18 months were associated with increased risk of symptomatic uterine rupture during a trial of labor afte r cesarean delivery compared with that for longer interdelivery intervals. (Obstet Gynecol 2001;97:175-7. (C) 2001 by The American College of Obstetri cians and Gynecologists.).