Case Report: Spontaneous complete uterine rupture in the second and third trimester of pregnancy

Objective: To summarize the clinical features, risk factors, and maternal and fetal outcomes of spontaneous complete uterine rupture during the second and third trimester of pregnancy, and to explore key aspects of early identification and management, especially in cases without prior cesarean section. This study aims to provide evidence-based insights for early warning and emergency intervention in clinical practice. Methods: This is a retrospective case series analysis of seven cases of spontaneous complete uterine rupture occurring in the second and third trimester of pregnancy. We analyzed patient demographics, obstetric history, gestational age at rupture, clinical presentation, management strategies, and outcomes. Descriptive statistical methods were employed, with continuous variables expressed as medians (range) and categorical variables as frequencies (percentages). Results: The median age of the seven women was 30 years old, with a median gestational age at rupture of 27 weeks. Among them, 57.1% (4/7) experienced rupture in the second trimester (<28 weeks), and 71.4% (5/7) had non-labor ruptures. 42.9% (3/7) of the cases involved women without a previous cesarean section. The most common clinical symptom was sudden onset of abdominal pain, often accompanied by shoulder pain, abnormal fetal heart rate, or vaginal bleeding, though these symptoms were non-specific. Surgical confirmation revealed rupture sites in the lower uterine segment (3 cases), fundus (3 cases), and cornua (1 case). Hemorrhagic shock (blood loss ≥ 2000 mL) occurred in 85.7% (6/7) of cases, with three cases complicated by placenta accreta spectrum (PAS). While all mothers survived, the perinatal mortality rate was 85.7% (6/7), with only one surviving fetus. Conclusion: Spontaneous complete uterine rupture during the second and third trimester of pregnancy typically presents as non-labor acute abdominal pain and may occur in women without a prior uterine surgery history, especially in the second trimester, where fetal outcomes are poor. Clinicians should maintain a high index of suspicion for uterine rupture in pregnant women presenting with acute abdominal pain, regardless of previous cesarean history. Early diagnosis and the establishment of a rapid, multidisciplinary emergency response are critical to improving maternal and fetal outcomes.