الفهرس 
Introduction and Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Summary
The number of deliveries by caesarean section has been
increasing steadily worldwide in recent decades. Although it is
often assumed that caesarean section improves neonatal
outcomes, there is no hard scientific evidence to support this.
The safety of caesarean section, however, has increased owing
to improvements in surgical and anaesthetic techniques,
increased safety of blood transfusion and routine use of
antibiotics and thromboprophylaxis.
As the incidence of caesarean deliveries rises,the
number of patients who face the decision between a trial of
labour (TOL) and repeat caesarean section delivery increases
Uterine rupture is an uncommon but potentially
catastrophic complication of a trial of VBAC. Several studies
have reported the perinatal risks of failed trial of labour and
uterine rupture in women attempting VBAC.
Studies have shown that the risk of uterine rupture in the
presence of a defective scar is directly related to the degree of
thinning of the lower uterine segment.
Ultrasound also has been used by clinicians to diagnose
uterine rupture before the onset of labour, and recently,
researchers have tried to predict which women may be at
increased risk of uterine rupture.
To measure the scar thickness, the most suitable time to
perform ultrasonography is from 36-38 weeks gestation, as this
allows for adequate lower segment development and avoids
problems of diagnosis when the presenting part is deep in the
pelvis and when the amniotic fluid is physiologically
decreased
Summary
74
Some authors have also tried to use
transvaginalsonography in the first trimester but with a limited
degree of success. They found slightly thinner total and
anterior lower uterine segment measurements in women with a
history of caesarean compared with women with an unscarred
uterus, but the difference was not significant
The aim of the current study was to measure the lower
uterine segment thickness of caesarean section scar using two
& three dimensional ultrasonography transabdominaly and
transvaginaly in women with at least previous one caesarean
section to assess accuracy by comparing the outcome of each
measurement to intraoperative visual assessment of the scar.
The current study included 30 women with at least
previous one caesarean section recruited from Ain Shams
university maternity hospital from June 2012 to June 2014.
The lower segment thickness was measured from the
muscularis mucosa of the bladder on the outer side to the
chorioamnionitic membrane inside by transabdominal and
transvaginal 2D & 3D ultrasound.
Transabdominal and transvaginal ultrasound scans
2D&3D were performed to all included women to measure the
thickness of the lower uterine segment. , the mean lower
uterine segment thickness was 3.6±2.3 mm& 5.4±4.3 mm³ by
2D &3D TAUS respectively and was 3.7±2.7 mm & 6.1±4.5
mm³ by 2D &3D TVUS respectively.
The lower uterine segment was inspected intraoperative
during the caesarean section to note the grade according to
Qureshi et.al classification. Birth weight was also measured.
There was highly significant statistical difference
between normal and abnormal grades as regard LUS thickness
using 2D&3D US (P<0. 01).
Summary
75
2D and 3D were perfect and reliable to predict uterine
scar defects AUC; 0.789% and 0.801%in transabdominal and
also 2D&3D were perfect and reliable to predict uterine scar
defects AUC; 0.811% and 0.845%.
The association criterion with 2D TAUS ≤ 2.95mm has
sensitivity 100%, specificity 60.87%, PPV 43.8% & NPV
100%, while to achieve the same sensitivity, specificity,
PPV&NPV the cut-off value with 2D ≤2.79 proved by the
ROC curve.
The association criterion with 3D TAUS ≤ 3.16 has
sensitivity 85.71%, specificity 86.96%, PPV66.7% &NPV
95.2%, while to achieve the same sensitivity, specificity,
PPV&NPV the cut-off value with 3D ≤2.35 proved by the
ROC curve.
The best association criterion values were with 2D
TAUS≤2.95mm , 3D TAUS ≤3.16mm,2D TVUS ≤2,79 and
3D TVUS ≤2.35 for predicting uterine scar defects (highest
diagnostic accuracy).2D, 3D TAUS and 2D ,3D TVUS were
reliable to predict uterine scar defects AUC; 0.789,0.801,0.811
and 0.845.