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What is Establishment of fetoplacental circulation seen at and explain in detail?
Ref. DC Dutta's Textbook of Obstetrics. Pg 36
 
Implantation of 12-16 cell stage occurs in the endometrium on the anterior and posterior wall of the body near the fundus on the 6th day following fertilization.

Then the deeper penetration of the human blastocyst is called interstitial implantation, which happens by approx. 13th day after fertilization
The fetal circulation is established by 21st days after fertilization