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1、Placenta PreviaA common vaginal bleeding in third trimesterXiru LiuThe First Affiliated Hospital of Chongqing Medical UniversityRequirementsMaster the definition,types,clinical manifestations,diagnosis and treatment principles.Be familiar with the pathogenesis,pathophysiology,differential diagnosis,
2、and maternal&fetal outcomes.Understand the etiology and prevention.Case A 34 yr-old pregnancy woman at 31 weeks is admitted to the obstetric ward.She woke up in the middle of the night in a pool of blood.No pain or uterine contractions.Inspection of the uterus shows the fetus appears transverse lie.
3、Fetal heart tones are regular at 145/min.On inspection her perineum is grossly bloody.Diagnosis?Treatment?General ConsiderationDefinition After 28 weeks gestation,any part of the placenta is implanted in the lower uterine segment,even even partially or totally covered the internal cervical os.partia
4、lly or totally covered the internal cervical os.Consequently the placenta is Consequently the placenta is in advance of the presenting part.u Incidence 0.24%1.57%(our country)0.5%0.90%(other countries)It is the major reason of hemorrhage in the third trimester pregnancyGeneral ConsiderationuuPlacent
5、a previa statePlacenta previa state（胎盘前置状态）（胎盘前置状态）（胎盘前置状态）（胎盘前置状态）28 weeks.35 years 2.multiparity 3.prior cesarean delivery:5 times 4.smokingEtiologySuccenturiate placentaClassificationuComplete placenta previa uPartial placenta previa uMarginal placenta previaComplete PPPartial PPMarginal PPClassi
6、ficationuPernicious placenta previa（凶险性前置胎盘）（凶险性前置胎盘）previous c-section+placenta previa placenta accreta:50%Manifestationu Unassociated to activity,often occurs during sleep,or sleeps in a pool of blood.u A few nulliparas no bleeding.u Cause of bleeding Mechanical separation Placentitis Rupture of t
7、he venous in the decidua basalisManifestationuThe time of onset of bleeding,the amount,the frequency is related to the types of placenta previa.Types TimeFrequency AmountComplete2832wmoremorePartial3236wmidmidMarginal36wlesslessSign:uAnemia or shock (1)repeated bleeding anemia (2)heavy bleeding shoc
8、kuAbnormal fetal position (1)a high presenting part (2)breech presentation(often)ManifestationDiagnosisuClinical symptoms and signsuSonography:the most important diagnoses methodsimplest,precise,safestDiagnosisuMRI:Useful but expensive,check the accretaDiagnosisuSpeculum examinationuVaginal examinat
9、ion:seldom useduRectal examination:useless and dangerousDiagnosisuCheck the placenta and membrane after delivery:The distance from edge of placenta to the rupture of the fetal membranes is less than 7cm.Differential diagnosisVascular previaCervix diseasesEffect to mother and fetusuObstetric hemorrha
10、ge uPlacenta accreta uAnemia and infection uPremature delivery and perinatal fetus high mortality rateTreatment principlePrinciple:uInhibit contractionuControl bleedinguCorrect anemiauPrevent infectionuPromote fetal lung maturityExpectant treatmentIndication:u34weeksuFetal weight 400ml)threaten to m
11、other or fetusu36th weekuMarginal PP with bleeding too much，cant delivery immediatelyu36th week,fetal distress uFetus death or severe malformationTermination of pregnancyuCesarean section Complete and partial placenta previa Huge bleedinguVaginal delivery Marginal placenta previa Head presentation P
12、rogress of delivery satisfactoryTermination of pregnancyuTreat postpartum hemorrhage.1.Promote uterine contractions.Oxytocin,massage uterus.Uterine B-lynch suture 背带式缝合背带式缝合.Pack uterine cavity with ribbon gauze 宫腔填塞纱条宫腔填塞纱条.2.Uterine artery ligation.3.Subtotal hysterectomy次全子宫切除次全子宫切除.Emergent transferupostpartum hemorrhageuPernicious placenta previa（凶险性前置胎（凶险性前置胎盘）盘）uControl contractionsuTransfusion of bloodOxytocin,massage uterineUterine B-lynch SuturePack uterine cavity with ribbon gauzeUterine artery ligation