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. SETTING: All the patients were under clinical management at the Institut Rhonalpin pour l'Etude de la Reproduction Humaine in Lyons, France. PATIENTS: Patients involved in the in vitro fertilization program have had their supernumerary embryos frozen according to the three protocols presented here. MAIN OUTCOME MEASURES: Embryo recovery after freezing and thawing. Clinical and ongoing pregnancies after embryo transfer (ET). RESULTS: A protocol including sucrose addition and reduction of steps in the preparation of the blastocysts for freezing gave us a 21% PR per transfer (15 ongoing) of 101 transfers (106 thawings). CONCLUSIONS: Freezing of cocultured human blastocysts allow good PRs. This can represent an alternative for repeated failures of ETs at early stages.

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. Long term or ultrashort stimulation of the ovaries after gonadotrophin releasing hormone analogue gave 55-60% blastocyst formation. Serum was not necessary to obtain blastocysts. When the embryos were cocultured, we observed an increase in the implantation rates per embryo in the pregnant patients. However, a real increase in the pregnancy rate per transfer was observed in a population of patients who had had repeated failures of embryo transfer. This observation is discussed as possibly bypassing an effect of uterine motility, but the overall beneficial effect has to be assessed in a double blind randomized study. It is probable that improvements will not be observed for all the indications for in vitro fertilization.