1-9周妇产科学课件产科学部分6.1placenta previa

1、Placenta PreviaA common vaginal bleeding in third trimestershao yongThe First Affiliated Hospital of Chongqing Medical UniversityRequirementsMaster the definition, types, clinical manifestations, diagnosis and treatment principles.Be familiar with the pathogenesis, pathophysiology, differential diag

2、nosis, and maternal & fetal es.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 transve

3、rse lie. 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 partially or totally covered the internal cervical

4、 os. Consequently the placenta is in advance of the presenting part. General Consideration Incidence 0.24%1.57% (our country) 0.5%0.90% (other countries) Nulliparas: 1/10001/1500 pregnancy Grandmultiparas: 1/20 pregnancy It is the major reason of hemorrhage in the third trimester pregnancyGeneral Co

5、nsiderationPlacenta previa state（胎盘前置状态） 35 years 2.multiparity 3.prior cesarean delivery: 5 times 4.smokingCauses 1. Endometrial abnormality 1)Scared or poorly vascularized endometrium in the corpus. 2)Curettage, Delivery, CS and infection of endometrium 2. Placental abnormality 1)Large placenta (m

6、ultiple pregnancy) 2)succenturiate lobe （副胎盘） 3. Delayed development of trophoblast cellEtiologyEtiologySuccenturiate placentaClassificationComplete placenta previa Partial placenta previa Marginal placenta previaComplete PPPartial PPMarginal PPLow-lying placenta（低置胎盘） The placenta is implanted in t

7、he lower uterine segment such that the placental edge does not reach the internal os, but is in close proximity to it.ClassificationMarginal PPLow-lying PClassificationPernicious placenta previa（凶险性前置胎盘） previous c-section + placenta previa placenta accreta: 50%ManifestationSymptom: Sudden, recurren

8、tly painless vaginal bleeding in third trimester.CHARACTER of bleeding PainlessManifestation Unassociated to activity , often occurs during sleep, or sleeps in a pool of blood. A few nulliparas no bleeding. Cause of bleeding Mechanical separation Placentitis Rupture of the venous in the decidua basa

9、lisManifestationThe time of onset of bleeding, the amount, the frequency is related to the types of placenta previa.Types TimeFrequency AmountComplete2832wmoremorePartial3236wmidmidMarginal36wlesslessSign:Abdominal findings: Uterus is soft, relaxed and no tender. Contraction may be palpated.Fetal he

10、art tones maybe disappear.ManifestationSign:Anemia or shock (1)repeated bleeding anemia (2)heavy bleeding shockAbnormal fetal position (1)a high presenting part (2)breech presentation (often)ManifestationDiagnosisClinical symptoms and signsSonography: the most important diagnoses methodsimplest, pre

11、cise, safestDiagnosisMRI: Useful but expensive, check the accretaDiagnosisSpeculum examinationVaginal examination: seldom usedRectal examination: useless and dangerousDiagnosisCheck the placenta and membrane after delivery: The distance from edge of placenta to the rupture of the fetal membranes is

12、less than 7cm.Differential diagnosis Placental abruptionpainful vaginal bleeding uterus tendernessDifferential diagnosisVascular previaCervix diseasesEffect to mother and fetusObstetric hemorrhage Placenta accreta Anemia and infection Premature delivery and perinatal fetus high mortality rateTreatme

13、nt principlePrinciple:Inhibit contractionControl bleedingCorrect anemiaPrevent infectionPromote fetal lung maturityTreatment methodExpectant treatment Termination of pregnancyEmergent transferExpectant treatmentIndication: 34weeksFetal weight 400ml) threaten to mother or fetus36th weekMarginal PP wi

14、th bleeding too much，cant delivery immediately36th week, fetal distress Fetus death or severe malformationTermination of pregnancyCesarean section Complete and partial placenta previa Huge bleedingVaginal delivery Marginal placenta previa Head presentation Progress of delivery satisfactoryTermination of pregnancyTreat postpartum hemorrhage. 1.Promote uterine contractions. Oxytocin, massage uterus. Uterine B-lynch suture 背带式缝合.Pack uterine cavity with ribbon gauze 宫腔填塞纱条. 2.Uterine artery ligation. 3.Subtotal hysterectomy次全子宫切