Results:Among 35 920 deliveries,incidence of placenta previa was 0.98%,that of placenta accreta was 0.089%,that of placenta previa complicated with placenta accreta was 0.05%.

• 结果:在35920例产妇中前置胎盘发生率为0.；98%25；胎盘植入的发生率为0