ABSTRACT
OBJECTIVES: Estimation of the anterior lower uterine segment (LUS) thickness difference who underwent prior cesarean delivery measured with transvaginal sonography at or after 36 gestational weeks (sonographic thickness) and a ruler during elective cesarean section (operation thickness) Methods: One hundred sixty women who underwent prior cesarean delivery had the thickness of their LUS measured with transvaginal sonography at or after 36 gestational weeks. The LUS thickness was measured with a ruler during elective cesarean section. We compared group I whose LUS was fairly well visualized 4 cm or more from the uterine cervix to group II which had less than 4 cm. RESULTS: The mean sonographic thickness of LUS was 1.7 0.8 mm and that of operation thickness was 1.9 0.5 mm. The mean difference of the two (thickness difference) was 0.5 0.5 mm. In 31.3% the sonographic thickness was same as the operation thickness and in 70.7% of the total with 0.5 mm or less difference, the sonographic thickness could be regarded as accurate. The thickness difference with the sonographic thickness with 2 mm or more was smaller than those with 1 mm or less (0.4 0.5; 0.6 0.6) and that of group I was smaller than that of group II (0.4 0.4; 0.9 0.6) (p< .05). CONCLUSION: The thickness difference was 0.5 0.5 mm and it was smaller when the LUS thickness is 2 mm or over, clearly visible 4 cm or over from the cervix.