placenta previa lin qi de. definition placenta previa: abnormal location of the placenta over,or in...
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PLACENTA PREVIA
Lin Qi De
Definition
Placenta previa: Abnormal
location of the placenta over ,or in
close proximity to the internal os.
Incidence: approximately 1 /250
pregnancy
nulliparas: 1/1000~1/1500
pregnancy
grandmultiparas: 1/20
ClassificationComplete (total) placenta previa: entire cervical os is covered
Partial placenta previa:the margin of the placenta extends across but not all of the internal os.
Marginal:edge of the placenta lies adjacent to the internal os
Low lying placenta:placenta is located near but not directly adjacent to the internal os.
EtiologyMechanism: abnormal vascularization
Predisposing factors:
•Twin pregnancy
•Increasing maternal age
•Increasing parity
•Previous cesarean section
diagnosisPainless vaginal bleed:
first bleeding episode is 29~30 weeks
Ultrasonography:
benefit in localizing the placenta and diagnosis placenta previa
CautionDouble setup vaginal examination
No digital vaginal or rectal examination is preformed in case of placenta previa . Only as a final and definitive event and only under conditions of double set up.
This procedure involves careful evaluation of the cervix in the operation room with full preparations for rapid cesarean section.
ManagementBasic management
•Initial hospitalization with hemodynamic stabilization
•Enforced bed rest
•Restrictions of activity
Expectant management
(allow for further fetal growth and maturation)
•Blood transfusion is given as
necessary
•Amniocentesis for fetal lung maturity
testing
•Cesarean birth if fetus is thought to
be mature
Indication of vaginal delivery
•Delivery can be accomplished with minimal blood loss
•Fetus is dead
•Major fetal malformation
Complication
•Placenta previa accreta
•Postpartum hemopphage
•Increasing maternal mortality and perinatal mortality