Inter- and intraobserver variability in sonographic measurement of the lower uterine segment after a previous Cesarean section.
OBJECTIVE
To evaluate the reproducibility of sonographic measurement of the lower uterine segment in pregnant women at term.


METHODS
Two independent observers performed transabdominal sonography on 129 women between 36 and 38 weeks of gestation who had had a previous Cesarean section. Sonography was performed when the patients had a full and a half-full bladder; in 100 patients, the measurements were also performed transvaginally, with the patients having an empty bladder. Agreement was quantified by the intraclass correlation coefficient and, using a cut-off of 3.5 mm, by the kappa coefficient.


RESULTS
The intraobserver agreement was generally high (intraclass correlation coefficient > 0.90). The interobserver agreement was higher on transvaginal (intraclass correlation coefficient, 0.94) compared with transabdominal (0.70 and 0.84, with full and half-full bladder, respectively) ultrasound. The kappa coefficient was 0.75 transvaginally, compared with 0.34 and 0.54 using the transabdominal approach, with full and half-full bladder, respectively.


CONCLUSIONS
The agreement between two observers for sonographic transvaginal measurement of the lower uterine segment can be considered good, compared with poor to moderate agreement using the transabdominal approach.
Jastrow
N
N
Obstetrics and Gynecology Department, University Hospital of Geneva, Switzerland. nijw@bluewin.ch
Antonelli
E
E
Robyr
R
R
Irion
O
O
Boulvain
M
M
D000328:Adult; D000704:Analysis of Variance; D002585:Cesarean Section; D005260:Female; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D011247:Pregnancy; D012306:Risk; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler / Q000379:methods; D016216:Ultrasonography, Prenatal / Q000379:methods; D014597:Uterine Rupture / Q000000981:diagnostic imaging*; D014599:Uterus / Q000000981:diagnostic imaging*; D016064:Vaginal Birth after Cesarean