[Ultrasound evaluation of uterine scar after segmental transverse cesarean surgery]

To evaluate the thickness of the lower uterine segment by transvaginal ultrasound in a group of non-pregnant women and to describe the morphologic findings in the scar of those submitted to cesarean section.

A retrospective study of 155 transvaginal ultrasound images obtained from premenopausal and non-pregnant women, conducted between January 2008 and November 2011. the subjects were divided into three groups: women who were never pregnant (Control Group I), women with previous vaginal deliveries (Control Group II) and women with previous cesarean section (Observation Group). We excluded women with a retroverted uterus, intrauterine device users, pregnant women and those with less than one year of tsince the last obstetrical event. The data were analyzed statistically with Statistica, version 8.0 software. ANOVA and LSD were used to compare the groups regarding quantitative variables and the Student's t-test was used to compare the thickness of the anterior and posterior isthmus. The Spearman correlation coefficient was calculated to estimate the association between quantitative variables. P values <0.05 were considered statistically significant.

There was significant difference between the thickness of the anterior and posterior isthmus only in the group of women with previous cesarean section. Comparing the groups two by two, no significant differences between the thickness of the anterior and posterior isthmus were observed in the Control Groups, but this difference was significant when we compared the Observation Group with each Control Group. In the Observation Group, no correlation was found between the thickness of the isthmus and the number of previous cesarean deliveries or the time elapsed since the last birth. A niche was found in the cesarean scar in 30.6% of the women in the Observation Group, 93% of whom complained of post-menstrual bleeding.

The relationship between the thickness of the anterior and posterior wall of the lower uterine segment by transvaginal ultrasound is a suitable method for the evaluation of the uterine lower segment in women with previous cesarean sections.