Neonatal morbidity associated with uterine rupture: What are the risk factors?

OBJECTIVE: The purpose of this study was to evaluate factors associated with severe metabolic acidosis or death in a situation of uterine rupture. STUDY DESIGN: A retrospective study was performed with review of charts and electronic monitoring strips. RESULTS: Between November 1988 and November 2000, a total of 23 cases of complete uterine rupture were identified from among 2233 trials of labor after a previous low transverse cesarean delivery. Nine neonates (39.1%) had severe metabolic acidosis (pH < 7.0); among these, hypoxic-ischemic encephalopathy was diagnosed in 3 neonates and another neonate died. Placental or fetal extrusion or both were associated with severe metabolic acidosis (P < .001) but not with the other factors (birth weight, induction of labor, use of oxytocin, use of epidural, and cervix dilatation). Two newborns with severe acidosis had impaired motor development even with an intervention time less than 18 minutes from the onset of prolonged deceleration to delivery. CONCLUSION: When uterine rupture occurs, placental or fetal extrusion was the most important factor associated with severe metabolic acidosis. Prompt intervention did not always prevent severe metabolic acidosis and neonatal morbidity.