Sonographic evaluation of the wall thickness of the lower uterine segment in patients with previous cesarean section

Abstract

In pregnant women with a history of cesarean section, wall thickness of the lower uterine segment may help determine the risk and safety of vaginal delivery. Determination of wall thickness may help identify the potential risk of uterine rupture in pregnant women who do not wish to have another cesarean section or who are not eligible for surgery due to other systemic disorders. In this study, 50 pregnant women with previous cesarean sections were evaluated with ultrasound preoperatively, and measurements of the lower uterine segment wall thickness were compared with intraoperative assessment of uterine thinning. These findings correlated highly with each other (sensitivity: 100%; specificity: 82% positive predictive value: 87%; negative predictive value: 100%), suggesting the reliability and safety of ultrasound in evaluating uterine wall thickness. © 1996 John Wiley & Sons, Inc.

Prediction of scar integrity and vaginal birth after caesarean delivery

“…The review comprises 12 studies published between 1988 and 2009 [12,[33][34][35][36][37][38][39][40][41][42][43] including together 1834 women with a previous low transverse caesarean hysterotomy who underwent ultrasound measurement of the thickness of the lower uterine segment at [35][36][37][38][39][40] gestational weeks. In seven of the 12 studies the full lower uterine segment thickness was measured [12,33,36,[38][39][40]42], in four studies the myometrial thickness was measured [34,35,37,43], and in one study both measurements were taken [41].…”

“…In seven of the 12 studies the full lower uterine segment thickness was measured [12,33,36,[38][39][40]42], in four studies the myometrial thickness was measured [34,35,37,43], and in one study both measurements were taken [41]. Because only three of the 12 studies reported the frequency of uterine rupture separately, the outcome measure was "uterine rupture or uterine dehiscence", i.e.…”

“…The cutoffs suggested for the full lower uterine segment thickness in the different studies varied between 2.0 mm and 3.5 mm and those for the myometrial thickness between 1.4 mm and 2.0 mm. It is of note that in nine of the 12 studies included in the review the ultrasound results were available to the staff managing the pregnancies and deliveries [33][34][35][38][39][40][41][42][43]. This is inappropriate when estimating sensitivity and specificity of a diagnostic test.…”

“…In studies reporting on measurements of the thickness of the lower uterine segment the measurement technique was described with varying detail [12,[33][34][35][36][37][38][39][40][41][42][43]. Therefore, it is unlikely that exactly the same transabdominal measurement technique or exactly the same transvaginal measurement technique was used in all studies: there may be differences between the degree of bladder filling, the site of measurement, the placement of the callipers, the number of measurements taken and in the measurement selected to be representative if more than one was taken.…”

Ultrasound finding and operative management of a uterine rupture during vaginal delivery after Cesarean section

“…Qureshi et al reported ≤ 2 mm as the criterion for poor healing of the uterine 8 . Preoperative ultrasound measurements of the lower uterine segment wall thickness also correlated well with the true intraoperative situs 9 .…”