The collagen substratum influences in vitro hatching and attachment of the mouse blastocyst in a serumless medium.

When a serumless medium is used for the in vitro growth and development of post-blastocyst mouse embryos, a collagen substratum causes a delay in the hatching from the zona pellucida. However, the collagen substratum is essential for blastocyst attachment and trophoblast cell outgrowth after hatching has taken place.