Characteristics of fetal heart rate tracings prior to uterine rupture

Objective: To identify the fetal heart rate patterns that occurred in a 2-h period of time preceding uterine rupture. Methods: The fetal monitor strip s and the medical records of patients with a confirmed diagnosis of uterine rupture were reviewed. These patients delivered at the University of Michi gan Hospital from January 1, 1985 to December 31, 1999 and were greater tha n or equal to 28 weeks gestational age. Asymptomatic uterine sear dehiscenc es were excluded. The weeks of gestation, the number of cesarean sections, the surgical findings, and the maternal complications were obtained from th e review of the maternal records. The fetal monitor strips for the 2 h prec eding the uterine rupture were analyzed, and the fetal heart rate patterns were classified. Results: During the study period, there were 11 patients i dentified with uterine rupture. Seven of the 11 (64%) had operative or post -operative complications. There were no maternal deaths. Review of the eigh t fetal heart rate tracings available revealed 7/8 (87.5%) with recurrent l ate decelerations and 4/8 (50%) with terminal bradycardia. All four of the patients with fetal bradycardia were preceded by recurrent late deceleratio ns (100%). Conclusions: The most common fetal heart rate abnormalities that occurred prior to uterine rupture Were recurrent late decelerations and br adycardia. The appearance of recurrent late decelerations may be an early s ign of impending uterine rupture. (C) 2001 International Federation of Gyne cology and Obstetrics. All rights reserved.