لینک دانلود و خرید پایین توضیحات

دسته بندی : پاورپوینت
نوع فایل : پاورپوینت بارداری چند جنینی.ppt( قابل ويرايش و آماده ارائه )
تعداد اسلاید 32 اسلاید
قسمتی از متن .ppt :



Multifetal 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 .
If division occurs between the fourth and eighth day ,Two amniotic sac will be covered with a common chorion diamniotic , monochorionic ,monozygotic .
If the amnion is established ,witch occurs about 8 days fertilization mono amniotic ,mono chorionic, monozygotic twin pregnancy will result .
If devision is after this , that is after formation of embryonic disk cleavage is incomplete and conjoined twins are formed .

شيوع
شيوع دوقلوهاي منوزيگوت تقريباً در تمام دنيا يكسان و حدود1 در هر 250 حاملگي است و به نژاد وسن و پاريتي ارتباطي ندارد .
متعاقب اينداكشن اووليشن ،شيوع دونيمه شدن اووم دو برابر ميشود.
شيوع دوقلوهاي دو تخمكي بطور قابل توجهي بوسيله نژاد،سن مادر و پاريتي و بخصوص داروهاي القا كننده اووليشن افزايش مي يابد .
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