الفهرس 
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Abstract
SUMMARY
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os.
Placenta accreta spectrum ( PAS ) is the general term applied to abnormal
adherence of the placental trophoblast to the uterine myometrium; it is also referred to as morbidly adherent placenta. the pooled prevalence of placenta previa is about 4 per 1000 births , PAS incidence approximately 1 in 1000 to 2000 pregnancies.
The major causes of PAS include placenta previa (placenta that partially or completely covers the cervical os) and previous cesarean delivery; the risk is greater when both factors are present and when the previa overlies the scar. The greater the number of previous cesarean deliveries, the higher the risk.
Prenatal screening and diagnosis are important so that the patient and her family can be counseled about the suspected placental abnormality and an appropriate site and plan for delivery can be developed.
Prenatal diagnosis of MAP is done mainly by imaging , 2-D grey scale and color Doppler ultrasound is the most important .
This study was carried out on 57patients attending the obstetrics outpatient clinic of Beni-Suef University Hospitalwhere 57 pregnant women with persistent placenta previa (after 28 weeks’ gestation) were enrolled into this study
Detailed medical history was taken from each patient followed by full general and local examination; accordingly patients were included or excluded from the study.
Patients Included in this study werePregnant women with persistent placenta previa (after 28 weeks’ gestation) implanted on the lower uterine segment.
Patients with this criteria was excluded if there was placenta previa posterior wall, unscarred uterus.
For each patient included in the study, the whole placenta was scanned in a systematic fashion using both gray-scale ultrasound and color flow mapping.
On gray-scale ultrasound imaging, we considered the presence of at least one of the following characteristics to indicate placenta accreta (including its variants, placenta increta and placenta percreta):
(1) Complete loss of the retroplacentalsonolucent zone.
(2) Thinning of Myometrium .
(3) Thinning or disruption of the hyperechoic uterine serosa–bladder interface.
(4) Presence of focal exophytic masses invading the urinary bladder.
(5) Presence of abnormal placental lacunae.
Likewise, the diagnosis of placenta accreta was regarded as positive when any one of these color Doppler criteria is present:
(1) Diffuse or focal lacunar flow pattern.
(2) Hypervascularity of the uterine–bladder interface with abnormal blood vessels linking the placenta to the bladder.
(3) Markedly dilated vessels over the peripheral subplacental region .
All the pregnancies enrolled in this study was delivered by cesarean section at our hospital with full availability of information on the delivery.
Results showed significant association between each 2-D ultrasound grey scale finding and the intraoperative diagnosis of morbid adherence, all were statistically significant P value < 0.05 except exophytic masses invading the urinary bladder was insignificant P value > 0.05.
It also show significant association between each 2-D color doppler ultrasound finding and the intraoperative diagnosis of morbid adherence, all were statistically significant P value < 0.05.
2-D grey scale findings of placenta and intra operative diagnosis of placenta adherence were analysed , the sensitivity of presence of Intra-placental blood lake for morbid adherence was 82.86 % and its specificity was 100%. The positive predictive value and the negative predictive value were 100 % and 78.6% respectively , the sensitivity of loss of the retro-placental sono-lucent Zone for morbid adherence was 88.57 % and its specificity was 77.72%. The positive predictive value and the negative predictive value were 86.1 % and 80.9% respectively, the sensitivity of thinning or disruption of the hyper-echoic serosa-bladder interface for morbid adherence was 40 % and its specificity was 90.9%. The positive predictive value and the negative predictive value were 87.5 % and 48.8% respectively, the sensitivity of exophytic masses invading the urinary bladder for morbid adherence was 11.4 % and its specificity was 100%. The positive predictive value and the negative predictive value were 100 % and 41.5% respectively, the sensitivity of thinning of myometrium for morbid adherence was 100% and its specificity was 63.4%. The positive predictive value and the negative predictive value were 81.4 % and 100% respectively, the sensitivity of number of lacunae for morbid adherence was 85.7% and its specificity was 100%. The positive predictive value and the negative predictive value were 100 % and 81.5% respectively.
2-D color doppler findings of placenta and intra operative diagnosis of placenta adherence were analyzed the sensitivity of Dilated vessels over the peripheral sub-placental region for morbid adherence was 100% and its specificity was 100%. The positive predictive value and the negative predictive value were 100 % and 100% respectively, the sensitivity of Hyper-vascularity of the uterine–bladder interface for morbid adherence was 100% and its specificity was 100%. The positive predictive value and the negative predictive value were 100 % and 100% respectively, the sensitivity of increased Lacunar flow for morbid adherence was 77.14% and its specificity was 81.8%. The positive predictive value and the negative predictive value were 87.1 % and 69.2% respectively.