Cesarean section scar defects: agreement between transvaginal sonographic findings with and without saline contrast enhancement.

OBJECTIVES: To determine the agreement between transvaginal ultrasound examinations performed before and at saline contrast sonohysterography (SCSH) with regard to number, size and shape of Cesarean section (CS) scar defects. METHODS: In all, 108 women underwent transvaginal ultrasound examination with SCSH at least 6 months after CS: 68 had undergone one CS, 32 two CSs and eight women had undergone at least three CSs. The ultrasound examiner was blinded to the number of CSs and to the obstetric history. The number and shape of CS scar defects were determined subjectively, and any scar defect was estimated subjectively to be large or not large. Measurements of the scar defects were also taken. Results obtained before and at SCSH were compared. RESULTS: Most scar defects were triangular in shape. The shape did not change at SCSH, but the ultrasound examiner found it easier to delineate the borders of the scar defects at SCSH than at unenhanced ultrasound examination. More scar defects were seen and more scar defects were classified as large at SCSH than before: among the 100 women who had undergone one or two CSs, 16 additional women had large defects at SCSH, whereas no woman with a large defect before SCSH had no defect or only a small defect at SCSH. The length and height of the defects were larger at SCSH than before: mean difference 2 mm and 1 mm in women who had undergone one CS, and mean difference 4 mm and 2 mm in the lowest-positioned scar in women who had undergone two CSs. CONCLUSIONS: In non-pregnant women CS scars were better evaluated at SCSH than at unenhanced ultrasound examination, because the demarcations of scar defects were more clearly delineated at SCSH than before. More defects were detected and more defects were classified as large at SCSH.

High prevalence of defects in Cesarean section scars at transvaginal ultrasound examination.

OBJECTIVES: To determine the ability to correctly identify Cesarean section scars, to estimate the prevalence of defective scars, and to determine the size and location of scar defects by transvaginal ultrasound imaging. METHODS: Two hundred and eighty-seven women underwent transvaginal ultrasound examination 6-9 months after delivery: 108 had undergone one Cesarean section, 43 had had two Cesarean sections, 11 had undergone at least three Cesarean sections, and 125 were primiparae who had delivered vaginally. The ultrasound examiner was blinded to the obstetric history until all scans had been evaluated. RESULTS: None of the 125 vaginally delivered women had a visible scar in the uterus, whereas all women who had undergone Cesarean section had at least one visible scar. Median myometrial thickness at the level of the isthmus was 11.6 mm in women who had only been delivered vaginally, and 8.3 mm, 6.7 mm and 4.7 mm in women who had undergone one, two and at least three Cesarean sections, respectively (P < 0.001). Scar defects were seen in 61% (66/108), 81% (35/43) and 100% (11/11) of the women who had undergone one, two and at least three Cesarean sections (P = 0.002); at least one defect was classified as large by the ultrasound examiner in 14% (15/108), 23% (10/43) and 45% (5/11) (P = 0.027), and at least one total defect was seen in 6% (7/108), 7% (3/43) and 18% (2/11) (P = 0.336). In women who had undergone one Cesarean section, the median distance between an intact scar and the internal cervical os was 4.6 (range, 0-19) mm, and that between a deficient scar and the internal cervical os was 0 (range, 0-26) mm (P < 0.001). CONCLUSIONS: Cesarean section scars can be detected reliably by ultrasound imaging. Myometrial thickness at the level of the isthmus uteri decreases with the number of Cesarean sections and the frequency of large scar defects increases. Scars with defects are located lower in the uterus than intact scars.