placenta previa is defined as a placenta implanted in the lower segment of the uterus
presenting ahead of the leading pole of the fetus It occurs in 2.8/1000 singleton
pregnancies and 3.9/1000 twin pregnancies and represents a significant clinical problem because the patient may need to be admitted to hospital for observation , she may need blood transfusion, and she is at risk for premature delivery.
The incidence of hysterectomy after Caesarean section (CS) for placenta previa is 5.3% (relative risk compared with those undergoing CS without placenta previa is 33). Perinatal mortality rates are three to four times higher than in normal pregnancies.