Is a trial of labor indicated after a prior cesarean delivery for dystocia when the estimated fetal weight is greater than the prior newborn's weight?

Abstract

DELIVERY FOR DYSTOCIA WHEN THE ESTIMATED FETAL WEIGHT IS GREATER THAN THE PRIOR NEWBORN’S WEIGHT? EMMANUEL BUJOLD, ISRAEL HENDLER, SUSAN BERMAN, SEAN BLACKWELL, ROBERT GAUTHIER, Wayne State University, Obstetrics and Gynecology, Detroit, MI Sainte-Justine Hospital, Obstetrics & Gynecology, Montreal, Quebec, Canada OBJECTIVE: To estimate if the rates of failed TOL and uterine rupture in patients with a prior cesarean delivery for dystocia are increased if the neonatal birth weight is higher than the one at the prior cesarean. STUDY DESIGN: Charts of all patients at term who had a trial of labor after a prior cesarean for dystocia in our institution between 1988 and 2002 were reviewed. The rates of successful VBAC, uterine rupture, and adverse obstetrical outcomes were associated with birth weight at the time of the prior cesarean, birth weight at the time of TOL, and the difference between the two. To adjust for confounding variables, univariate and multivariate regression analysis were performed . RESULTS: Out of 1015 patients with a prior cesarean for dystocia, 191 (19%) had a prior baby over 4000 g, 138 (14%) had a neonate with an actual birth weight over 4000 g, and 470 (46%) had a neonate with an actual birth weight greater than the birth weight of the prior newborn. In a univariate analysis, a neonate > 4000 g at the time of TOL (51% vs 69%, P 4000 g at the time of TOL was associated with a failed TOL (see Table). None of those three factors related to neonatal birth weight were associated with a higher risk of uterine rupture. CONCLUSION: Contrary to popular belief, the prior neonatal birth weight is not related to obstetrical outcomes in patients with a prior history of cesarean for dystocia.