妇产科学教学课件：6-1前置胎盘.ppt

A 34 yr-old pregnant woman at 32 weeks is admitted to the obstetric ward. She woke up in the middle night and in a pool of blood.No pain or uterine contractions. Fetal heart tones are regular at 145/min.Case Preterm labor → NICUHemorrhagic shock → ICUuterusplacenta Obstetrician（“惨”科医生）Pregnancy is a miracle ! Hemorrhage is a disaster !TVReality Etiology Classification Epidemiology impact Definition1 ManagementCatalog23456Clinical manifestationDiagnosis Differential diagnosis DefinitionPlacenta previa： After 28 gestational weeks, any part of the placenta is implanted in the lower uterine segment, even partially or totally covered the internal cervical os. ≥28W ！ EtiologyThe exact cause of placenta previa is still unknown…… Endometrial abnormality: previous curettage, cesarean section, infection of endometrium Placental abnormality: multiple pregnancy, succenturiate lobeDelayed development of trophoblast TwinSuccenturiate lobeNormal sigleton EtiologyThe exact cause of placenta previa is still unknown…… Endometrial abnormality: previous curettage(刮宫), cesarean section, infection of endometrium Placental abnormality: multiple pregnancy, succenturiate lobe(副胎盘)Delayed development of trophoblast ClassificationComplete/Total —the internal os is covered completely by placentaPartial—the internal os is partially covered by placentaMarginal—the edge of the placenta is at the margin of the internal osRelationship between the edge of placenta and the internal cervical os Partial MarginalComplete Clinical manifestation Symptoms: sudden, recurrently painless vaginal bleeding in third trimesterPainless Bleeding mechanismLower uterine segment keep extensionfetal membranes and deciduas mismatchplacenta separateblood vessel rupture Clinical features of bleedingTotal Early (20-28wks) Large amount Several timesBleeding volumePartialMarginal Between total and marginal Late (37-40WKS or in labor ) Less bleeding P