Risk factors and morbidity in patients with placenta previa accreta compared to placenta previa non-accreta

Placenta accreta is associated with high morbidity and most cases occur with placenta previa. This study was carried out in an attempt to define risk factors for placenta accreta in cases of placenta previa and to quantify the increased morbidity of placenta previa accreta in comparison to placenta previa alone.

The records of all patients delivered by cesarean section (CS) for placenta previa and accreta during the seven-year period from 1990 to 1996, inclusive, were reviewed. Data regarding the demographic features, previous CS, the incidence of hysterectomy and postpartum morbidity were analyzed.

Out of 23070 deliveries 110 (0.48%) had placenta previa, twelve (0.05%) of whom had placenta previa accreta. There was no significant difference in age and parity. Patients with a history of previous CS showed a significant increase in the incidence of placenta previa accreta (p=0.001). The percentage of accreta increased linearly from 4.1% in patients with no CS to 60% in patients who had had three or more CS. Postpartum hemorrhage and emergency hysterectomy were significantly higher among the previa accreta patients compared with the previa patients alone (p<0.001; p<0.001, respectively).

In the presence of a previous history of CS, patients with antepartum diagnosis of placenta previa are considered to be at a greater risk for having placenta accreta. The risk increases with the increase in the number of previous CS. Patients with placenta previa accreta have a significantly higher incidence of PPH and are more likely to undergo emergency hysterectomy.