Abstract:

Obstetric risks have increased among pregnancies following previous cesarean section deliveries. Placenta accreta and cesarean scar pregnancies, as abnormal placentation entities, represent two important clinical manifestations. Placenta accreta is characterised with a placenta that is abnormally adherent to uterine cavity because of the absence of decidua basalis and presence of incompletely developed fibrinoid layer. Placenta accreta occurs in 5-10% of pregnancies complicated with placenta previa. Placenta increta and percreta are the other serious abnormalities of placental implantation that demonstrates invasion of chorionic villi into the myometrium and uterine serosa respectively. Placenta accreta has been seen rarely as 1 in 30.000 births in 1950’s but the incidence of placenta accreta has increased recently to 1 in 553 and 2510 deliveries in parallel with increased cesarean sectio deliveries. Previous uterine surgery is the most important risk factor for placenta accreta. Thin, defectively formed or absent decidua basalis layer can not show resistance to deep penetration of trophoblasts and placenta invades this pathological region of uterus that has previously been traumatised by uterine surgery. Abnormal placental implantation impedes placental removal spontaneously following delivery. The first clinical sign of placenta accreta is profuse and life threatening bleeding that occurs during manuel removal of placenta. Placenta accreta is diagnosed with characteristic signs during prenatal ultrasound examination including color doppler modalities. Magnetic resonance imaging is also helpful for equivocal cases. Massive bleeding and resultant disseminated intravascular coagulation, adult respiratuar distress syndrome, renal insufficiency, unplanned surgery and death are serious complications of placenta accreta. Preoperative and intraoperative management strategies of placenta accreta have been detailed in this review.

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