الفهرس 
Anatomy of normal PlacentaOnly 14 pages are availabe for public view
 |  | from | 117 |  |  |
| | | from | 117 | | |
Abstract
The term Placenta accreta is used to describe any
placental implantation in which there is abnormally firm
adherence to the uterine wall. As the consequence of partial or
total absence of the decidua basalis and imperfect development
of the fibrinoid layer, placental villi are attached to the
myometrium. In Placenta Increta, the placenta invades the
myometrium, whereas in Placenta Percreta, it penetrates
through the myometrium and serosa, sometimes into adjacent
organs, such as the bladder.
The incidence of placenta accreta has increased 10 fold in
the past 50 years and now occurs with a frequency of 1 per
2,500 deliveries. The incidence of placenta accreta is
increasing, primarily as a consequence of rising cesarean
delivery rates.
The primary complication is hemorrhage during delivery
because the placenta has difficulty separating from the uterine
wall. The maternal mortality risk may reach 7%, and the
extensive surgically related morbidities include massive
transfusion, infection urologic injury, and fistula formation.
It is important to make the diagnosis of placenta accreta
prenatally because this allows effective management planning
to minimize morbidity.
Summary and Conclusion
- 84 -
Predicting adherent placenta prenatally with the use of
ultrasonography is becoming increasingly common. The
sonographic features suggestive of placenta accreta include:
- Irregularly shaped placental lacunae [vascular spaces]
within the placenta.
- Thinning of the myometrium overlying the placenta
- Loss of the retoplacental ’’clear space”
- Protrusion of the placenta into the bladder.
MR imaging shows the placenta in a gravid uterus as
moderately hyperintense on T2-weighted images and allows
differentiation between the placenta and the hypointense
myometrium. Placenta accreta and increta are suggested by
thinning, irregularity, or focal disruption of the subjacent
myometrium. Placenta percreta is suggested by extension of the
placenta transmurally through the myometrium.
A two-stage protocol for evaluating women at high risk
for placenta accreta, which uses ultrasonography first, and then
MRI for cases with inconclusive ultrasound features, will
optimize diagnostic accuracy.