Freezing cocultured human blastocysts.

Objective: To determine the possibility of obtaining good pregnancy rates (PRs) after freezing and thawing cocultured blastocysts.

Design: Human blastocysts were frozen first according to a protocol available from literature. Two other protocols including the addition of glycerol were designed to improve the results.

Coculture of embryos on Vero cells and transfer of blastocysts in humans.

Preliminary results are presented concerning the first clinical application of cocultures of human embryos. In the experimental group, the embryos were cultured and transferred on day 5 post-insemination. Blastocyst formation was not dependent upon the stimulation regimen.