placenta previa 前置胎盘

胎盘 宫体 宫颈

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.

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

Classification Complete placenta previa partial placenta previa marginal placenta previa

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

diagnosis history signs vaginal examination ultrasound examination inspection placenta after labor

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 ）

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

Prevention prevent injury of endometrium consult on time treat correctly

treatment Expectant therapy terminating pregnancy preventing infection

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

terminating pregnancy cesarean section vaginal delivery