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
epidemiology Labor and delivery between28-36+6 weeks 5%-10% be the leading cause of perinatal morbidity and mortality Survival rates have increased and morbidity has decreased because of technologic advances
Definition Fetal distress is defined as depletion of oxygen and accumulation of carbon dioxide,leading to a state of \hypoxia and acidosis during intra-uterine life