باوربوینت درمورد بارداری چند جنین

فرمت فایل باوربوینت تعداد اسلاید29   بارداری چند جنین   ¨ ¨Multi fetal pregnancy ¨Etiology : ¨More commonly fertilization of two ova with tow sperm         double ovum or fratermal or  dizygotic twins ¨About tow third. ¨A bout one third as often ¨One fertilized ovum divided into two similar structures, into a separate individual that we call it a single ovum – monozygotic or Identical twins ¨Either or both process may be involved in the formation of high number of fetuses . ¨Genesis of monozygotic twins ¨If division occurs within first 72 hours before the inner cell mass is formed and the outer  layer of blastocyst is not commited to chorion , They will evolve  two embryoes ,with diamniotic  ,dichorionic monozygotic. ¨The frecuency     18-36% ¨ ¨There may be  two distinct placenta or may be a single fused placenta . …