胎盘早剥 Obstetrics is\bloody business Even though the maternal mortality rate has been reduced dramatically by hospitalization for delivery and the availability of blood for transfusion, death from hemorrhage remains prominent in the majority reports From willams obstetrics
General considerations Definition In placenta previa, the placenta is implanted in the lower uterine segment and located over the internal os. It constitutes an obstruction of descent of the presenting part. Main cause of obstetrical hemorrhage Incidence 0.24%-1.57% (our country)
Definition Placenta previa: Abnormal location- of the placenta over,orin close proximity to the internal os. Incidence: approximately 1 /250 pregnancy nulliparas: 1/1000~1/1500 pregnancy grandmultiparas: 1/20
Normal Pregnancy Pregnand The course that the embryo and the fetus grow in the maternal body Stages f pregnancy Early pregnancy: $12 weeks Mid pregnancy:≥13 weeks,≤27 weeks Late pregnancy: 228 weeks Term pregnancy:≥37 weeks,<42 weeks