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
Definition Preterm Labor: Labor occurring prior to the completion of 37 weeks' of gestation (228 weeks), or 196-258 days from the last menstrual period (LMP)
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