The rotational thromboelastogram (ROTEM) test can be performed on patients with placenta previa/accreta/increta/percreta who have a high likelihood of massive bleeding, and the predictors can be identified by comparing the patients who actually show massive bleeding with those who do not.

Applying these predictive factors to pregnant women undergoing cesarean section after diagnosis of placenta previa/accreta/increta/percreta, it will be advantageous for the perioperative management because it is possible to select pregnant women with a factor of massive bleeding.

Inclusion Criteria:

• Cesarean section under spinal anesthesia
• Placenta previa
• Placenta accreta
• Placenta increta
• Placenta percreta

Exclusion Criteria:

• Coagulopathy
• Medication with antiplatelets or anticoagulants

Pregnant women over 20 years old who are scheduled for cesarean section under spinal anesthesia after diagnosis of placenta previa/increta/percreta/accreta