To investigate the clinical features and treatment of placenta previa complicated with previous caesarean section. Methods The clinical data of 29 patients with placenta previa complicated with a previous caesarean section (RCS group) admitted in Peking Union Medical College Hospital during a period from 2003 to 2011 were retrospectively reviewed and compared with those of 243 patients with placenta previa without a previous caesarean section (FCS group) during the same period. Results There was no difference in the mean age (28.9±3.6 vs.28.1±4.5 years) and the average gravidity (2.35±1.48 vs.2.21±1.53) between RCS group and FCS group (all P>0.05).The RCS group had more preterm births (24.1% vs.13.2%)

complete placenta previa (55.2% vs.4.9%)

placenta accreta (34.5% vs.2.5%)

more blood loss during caesarean section (1412±602 vs.648±265 mL)

blood transfusion (51.7% vs.4.9%)

disseminated intravascular coagulation (13.8% vs.2.1%)

and obstetric hysterectomy (13.8% vs.0.8%) than the FCS group (all P<0.05).The preterm infant rate (30.0% vs.13.0%)

neonatal asphyxia rate (10.0% vs.4.9%)

and perinatal mortality rate (6.7% vs.0.4%) of the RCS group were higher than those of the FCS group (all P<0.05). Conclusions More patients had complete placenta previa and placenta accreta

postpartum hemorrhage

transfusion

uterine packing

obstetric hysterectomy

and perinatal morbidity in the placenta previa patients with previous caesarean section.The patient should be informed of the risk and unnecessary first cesarean sections should be avoided.