妇产科学课件：前置胎盘（英文版)

1、单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Placenta previa,Definition,the placenta is implanted partially or completely over the lower uterine segment within the zone of effacement and dilatation of the cervix.The placenta lies below the fetal presentation.,After 28 weeks,Placenta previa is a severe obstetric complication.,in the second and third trimesters of pregnancy.,serious morbidity and mortality to both the fetus and the mother.,the commonest causes of antepartum haemorrhage.(account for

2、 20%),Incidence,approximately 0.5%-1%of all pregnancy,account for 20%of all cases of antepartum hemorrhage.,90%of patient will be multipara.,the major reason of hemorrhage:when the lower uterine segment is increasing in length,and shearing forces between the trophoblast and the maternal blood sinuses.,Incidence,The first episode of bleeding occurs:,60%-after 36weeks of gestational age.,30%-between 32-36weeks of gestational age.,10%-before 32weeks of gestational age.,Etiology,The etiology of plac

3、enta previa is not so clear,may be multifactorial.Eg.multiparity,multiple gestations,maternal advanced age(35yrs),previous cesarean delivery,previous abortion,and infaust living habit(smoking,drug abuse).Uterine paramorphia,the patient who received assisted reproductive techniques.,Etiology,1.Endometrial lesion or injury.The common causes:abortion,curettage,puerperal infection,cesarean section,operative history of uterus,pelvic inflammation,.,Endometrial inflammation or atrophic lesions,poorly v

4、ascularized endometrium in pregnancy and insufficiency of placenta perfusion.To intake more nutrients the placenta increased its surface and extend to the lower uterine segment.,scarring in the lower segment of the uterus-hamper the removal of the placenta.ART make the difference between the endometrium and fetus development.,Etiology,2.placental abnormality(size and shape),twin pregnancy-increased placental surface area,succenturiate placenta,pseudoplacenta,ring-shaped placenta,placenta membran

5、acea,placenta multipartita,placenta multiples etc.,Etiology,3.The retardation of zygote growth,when the zygote reached uterine cavity,trophoblast is not prepared for implantation,so the zygote continue to move,at last implanted in the lower segment of the uterus.,Classification,Complete or central placenta previa,Partial placenta previa,Marginal placenta previa,Another Classification is Low-lying placenta.,Complete or central placenta previa,Partial placenta previa,Marginal placenta previa,Class

6、ification,According to the danger of the disease,：,pernicious placenta previa,Non-pernicious placenta previa,Note:,The diagnosis is according to the last examination before the termination of pregnancy.,Clinical manifestation,1.symptom:vaginal bleeding,Characters:Painless,in the third trimester,sudden onset,causeless,recurrent,Unrelated to activity,often occurs during sleep,(2)Reasons:,Mechanical separation,Formation of the lower segment(,isthmus uteri,)or effacement and dilatation of cervix,Not

7、e:placenta lies in the posterior portion of the lower uterine segment-difficult to ascertain.-high rate of missed diagnosis,transvaginal ultrasonography,transabdominal approach.,(3)The time of onset of bleeding,the amount,the frequency is related to type of placenta previa,type,onset,amount,Frequency,Central,Earlier,28,th,week,Severe,shock,more,Partial,Between central and marginal,between central and marginal,Marginal,Late,3740 weeks,slight,less,note:,A few patients even reach term without bleed

8、ing.For these patient,we should pay more attention to placenta increta.,2.Signs:,Anemia and shock,Abdominal exam,Uterus,：,soft,relaxed,and nontender.,The infant will present in an oblique or transverse lie,in about 15%of cases.,fetal distress,(repeatedly hemorrhage or massive hemorrhage.),Diagnosis,1.Clinical symptoms and signs,2.Sonography:rapid,simplest,precise,safest,MRI,Ultrasonography,the diagnosis of placenta previa is based upon results of ultrasound examination.,A simple,precise,and safe

9、 method to visualize the placenta,accuracy rate is over 95%,MRI,MRI has the advantages to placenta implanted in the posterior uterine wall,oligohydramnios,placenta increta.,Diagnosis,3.Diagnoses in parturition,(1)Cesarean section,(2)Vaginal delivery,If the distance between the rupture of the membrane and the placental margin is 7cm,it indicates placenta previa.,Whether there has clot cohere to the maternal surface of placenta previa or not.,Whether there has ruptured vessel in the placental marg

10、in.,Differential diagnosis,1.Cord velamentous insertion,2.Rupture of the marginal sinus,Differential diagnosis,3.Placental abruption,Placental abruption is the other major cause of vaginal bleeding in pregnancy.,4.,Bleeding of cervix and vagina,Complications,Maternal:,Postpartum hemorrhage,shock,death,Puerperal infection,Placenta increta,Amniotic fluid embolism,Fetus:,Fetal distress,Preterm delivery,Perinatal mortality rate is increased,Treatment,Principle:,Tocolysis,hemostasis,correct anemia,pr

《妇产科学课件：前置胎盘（英文版)》由会员第***分享，可在线阅读，更多相关《妇产科学课件：前置胎盘（英文版)》请在金锄头文库上搜索。