Rupture of the scarred and unscarred gravid uterus: Outcomes and risk factors analysis

Objective: To study the maternal and fetal outcomes and assess the risk factors in patients with rupture at the lower-segment or non-lower-segment scarred, or unscarred gravid uterus. Materials and Methods: Gravid patients with uterine rupture were retrospectively collected in Chang-Gung Memorial Hospital from November 2004 to July 2017. The rupture timing and location in association with maternal and fetal outcomes were collected as well as the possible risk factors including surgical history and interval prior to conception were analyzed. Results: Thirty patients were included [mean age (±SEM), 34.4 ± 0.7 years; mean body mass index, 25.0 ± 0.6 kg/m] with mean onset of rupture at 34.2 ± 0.9 weeks, in which, 12 occurred at term and 18 at preterm (range 20-34 weeks). Four fetal demises, 22 transferals to neonatal intensive care unit, and 17 maternal blood transfusions without maternal mortality were noted. Twenty-two patients presented with acute abdominal pain and/or abnormal fetal heart rate tracing were managed with emergent cesarean delivery. Four ruptures were found in postpartum of vaginal delivery, in which 3 were after trials of labor after cesarean delivery and 1 was unscarred uterus, and two of the four eventually underwent hysterectomy. Unscarred uterus (n = 6) without identifiable risk factor ruptured in significantly later gestation associated with higher fetal birthweights than those of the scarred uterus (n = 24) (both p < 0.05), both of which yielded morbidity. The rupture timing between patients of non-lower-segment scar (n = 14) and lower-segment scar (n = 10) were not significantly different. Conclusion: Rupture of gravid uterus prevalently occurred after 30 weeks of gestation with remarkable morbidity. Unscarred uterus could rupture in later gestation than the scarred ones without identifiable risk factor. Alertness to the acute abdominal pain, atypical from uterine contraction or the suspicious fetal heart rate tracing is the key to the timely rescue and successful management.