This work was supported by the National Basic Research Program of China (2011CB944400, 2011CB710905, 2012CB944702 and 2015CB943000), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA04020202-20 and XDA04020419) and the National Natural Science Foundation of China (31200879 and 31300957).
Dear Editor, In mammalian species, the window of implantation is defined as a limited period when implantation-competent blastocyst can interact with the receptive endometrium [1]. Besides the acquisition of blastocys...