Risk Factors and Clinical Presentation of Uterine Rupture in the Unscarred Uterus: A Case Control Study

Purpose: The aim of our study was to determine the risk factors and to describe the clinical presentation of women with uterine rupture without previous caesarean delivery. Methods: Case-control study involving all cases of uterine rupture in the unscarred uterus detected during labour or in the post-partum between January 1, 2004 and April 1, 2016. For the control we included four controls for one case among all the patients with no record of previous caesarean delivery and planned vaginal delivery in the same period. For each woman we collected the maternal and labour characteristics. We evaluate the risk factors of uterine rupture, using Bayesian’s method. Each result is presented as a differential with a 95% credibility interval and the probability that the difference is greater or less than 0 (or 1 for the odds ratio). Results: We identified seven cases of spontaneous rupture. Deep and variable decelerations were the most frequent abnormal fetal rhythm. There was not maternal death but one neonatal death. Multiparity (estimated difference of 1.59 (95% CI=0.55, 2.95) Pr (diff>0)=1); use of oxytocin (OR=26.4 (95% CI=1.79-103) Pr (diff>0)=0.99), induced labour (OR=14 (95% CI=2.5, 122) Pr (diff>0)=1) ultrasound macrosomia (OR 30.0 (95% CI=4.3-327) Pr (diff>0)=0.99), were associated with uterine rupture. Conclusion: Even in developed countries, uterine rupture remains a serious complication with high maternal and fetal morbidity. We identified some risk factors like multiparity, induction of labour and macrosomia. These factors can help us to detect earlier this complication.