Register for Prediction of Complete Uterine Rupture by Sonographic Evaluation of the Lower Uterine Segment
2Nicole Jastrom1,
Robert J. Gauthier1,
Jessica Simoneau2, Suzanne
Brunet2, Emmanuel Bujold3
1Université de Montréal,
Obstetrics and Gynecology, Montréal, Quebec;
2Hôpital Sainte-Justine,
Quebec; 3Université Laval,
Obstetrics & Gynecology, Québec, Quebec
OBJECTIVE: Several studies have shown that sonographic evaluation of lower uterine segment (LUS) thickness can predict uterine scar defects by either full LUS thickness or muscular layer measurement. We aimed to establish the predictive value of both measurements for complete uterine rupture.
STUDY DESIGN: A prospective cohort study of women with prior cesarean was conducted. LUS thickness was measured between 35 and 38 weeks of gestation. The thinnest measurement was conserved as the dependent variable. Receiver operating curve (ROC) analyses determined the optimal cut-off value for sensitivity and specificity. Potential confounding factors were considered by regression analyses.
RESULTS: 236 women were included. Three cases of complete uterine rupture and 6 cases of uterine scar dehiscence were reported. ROC analyses demonstrated significant associations between the risk of uterine rupture during trials of labour (TOL) and full LUS thickness (area under the curve (AUC) = 88%, p=0.02), but not with muscular layer measurement (AUC = 66%, p=0.34). Uterine scar defect at the time of laparotomy was associated with both full LUS thickness (AUC = 71%, p=0.03) and muscular layer measurement (AUC=70%, p=0.047). Full LUS thickness under 2.3 mm was associated with a sensitivity of 100% and a specificity of 75% for complete uterine rupture. In univariate analyses, only full LUS thickness below 2.3 mm and single-layer closure were associated with uterine rupture during TOL. The combination of full LUS thickness under 2.3 mm and single-layer closure was strongly associated with uterine rupture (relative risk: 21.8, 95%CI: 2.1 – 222, p<0.001) during TOL.
CONCLUSION: Measurement of full LUS thickness near term could lead to a major reduction of uterine rupture in women contemplating vaginal birth after cesarean. The combination of single-layer closure and full LUS thickness below 2.3 mm is related to a very high risk of uterine rupture and should preclude a TOL.
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