Deficient lower-segment Cesarean section scars: prevalence and risk factors.

OBJECTIVE

To examine the sonographic features of transverse lower-segment uterine Cesarean section scars in non-pregnant, premenopausal women and to identify factors associated with scar deficiency.

METHODS

Non-pregnant, premenopausal women with histories of previous transverse lower-segment Cesarean sections, who were referred for an ultrasound scan for a variety of gynecological indications, were included in this study. An attempt was made to identify the uterine scars on transvaginal ultrasound scan and to describe their locations and morphological features. Various demographic, clinical and ultrasound data were examined in order to identify factors associated with deficient scars. Deficient scars were defined as detectable myometrial thinning at the site of the Cesarean section scar.

RESULTS

Lower-segment uterine scars were detected in 321/324 (99.1%; 95% CI, 98.0-100) women with a history of previous Cesarean section. Sixty-three (19.4%; 95% CI, 15.1-23.8) women had evidence of deficient Cesarean scars. Using multivariate analysis, a history of multiple Cesarean sections, uterine retroflexion and the inability to visualize all Cesarean scars in women with previous multiple Cesarean sections were all shown to be significantly associated with deficient scars.

CONCLUSION

Deficient uterine scars are a frequent finding in women with a history of previous Cesarean section. The risk of scar deficiency is increased in women with a retroflexed uterus and in those who have undergone multiple Cesarean sections.