Author(s): Shubhada Suhas Jajoo, Joseph Stalin Augusti Mary Priyanka

BACKGROUND Caesarean section (Sectio Caesarea) is a surgical method for the completion of delivery. After various historical modifications of operative techniques, modern approach consists in the transverse dissection of the anterior wall of the uterus. The rate of vaginal birth after caesarean section was significantly reduced from year to year and the rate of repeated caesarean section is increased during the past 10 years. Evaluation of scar thickness is done by ultrasound, but it is still debatable size of thick scar that would be guiding “cut-off value” for the completion of the delivery method. To better assess the risk of uterine rupture, some authors have proposed sonographic measurement of lower uterine segment thickness near term assuming that there is an inverse correlation between LUS thickness and the risk of uterine scar defect. Therefore, this assessment for the management of women with prior CS may increase safety during labour by selecting women with the lowest risk of uterine rupture. The aim of the study is to study the diagnostic accuracy of sonographic measurements of the Lower Uterine Segment (LUS) thickness near term in predicting uterine scar defects in women with prior Caesarean Section (CS). We aim to ascertain the best cut-off values for predicting uterine rupture. MATERIALS AND METHODS 100 antenatal women with history of previous one LSCS who come to attend antenatal clinic will be assessed for scar thickness by transabdominal ultrasonography and its correlation with intraoperative findings. This prospective longitudinal study was conducted for 1 year after IEC approval with inclusion criteria previous one LSCS. Exclusion criteria- 1) Previous myomectomy scar; 2) Previous 2 LSCS; 3) Previous hysterotomy scar. RESULTS Our findings indicate that there is a strong association between degree of LUS thinning measured near term and the risk of uterine scar defect at birth. In our study, optimal cut-off value for predicting uterine scar defect is 3.9 mm. CONCLUSION Sonographic measurement of scar thickness is an excellent method for safely predicting the risk of scar dehiscence/rupture in women with previous one CS. With different cut-off values in different studies, critical thickness of LUS for evaluation of scar defects is need of the hour to save many pregnant women and babies from significant morbidity and mortality.