Implantation or nidation
Implantation or nidation
Attachment of the developing embryo to the endometrium
Occurs in three stages in domestic animals: Apposition of the blastocyst or foetal membranes to the uterine epithelium
Adhesion
Firm attachment or invasion of the endometrium
INTERSTITIAL or INVASIVE IMPLANTATION
Primates and guinea pigs
Blastocyst implants itself interstitially by passing through the uterine epithelium and becoming completely cut off from the uterine lumen.
ECCENTRIC IMPLANTATION
ECCENTRIC IMPLANTATION
remains small and becomes lodged in a fold of the uterine lumen, where it implants itself.