1. placenta previa
前置胎盘

2. 胎盘 宫体 宫颈

3. definition
The normal placenta attaches to the anterior. Posterior or lateral wall of the uterine body . If it is attaches to the lower segment of the uterus, over the cervical os, lower than fetal presentation, it is called placenta previa.

4. etiology Scarred or poorly endometrium or infection
placenta is large than normal
abnormal placenta
the fertilized ovum develops slowly

5. Classification Complete placenta previa partial placenta previa
marginal placenta previa

6. Clinical manifestations
Mean symptoms
causeless
hemorrhage painless
(all the 3rd trimester) repeated
signs

7. diagnosis history signs vaginal examination ultrasound examination
inspection placenta after labor

8. Differential diagnosis
Placental abruption
others: cervical disease
(cervical polyps; erosion or
carcinoma of cervix ; cervicitis)
rupture of marginal sinus
（ 边缘窦破裂）
rupture of vasa previa
（血管前置破裂 ）

9. Influence on mother and fetus
Maternal hemorrhage shock
placenta accreta（胎盘植入）
puerperal infection
premature delivery and fetal death

10. Prevention prevent injury of endometrium consult on time
treat correctly

11. treatment
Expectant therapy
terminating pregnancy
preventing infection

12. Expectant therapy Expectant theray A indication : <37w
<2300g 
bleeding is little in amount
B methods: hospitalization
valium
to correct anemia
inhibiting to uterine contraction
improving maturity of fetal lungs

13. terminating pregnancy
cesarean section
vaginal delivery