ENDOMETRIUM PREPARATION WITH EXOGENOUS ESTRADIOL AND PROGESTERONE FOR THE TRANSFER OF CRYOPRESERVED BLASTOCYSTS

Objective: To determine the implantation rates of cryopreserved blastocysts using controlled E(2) and P replacement cycles in women with functioning ovaries. Design: Retrospective clinical study. Setting: University teaching hospital. Patients: Infertile women with cryopreserved blastocysts obtained from previous IVF attempts. Interventions: Exogenous E(2) was administered orally from cycle day 1 and P was started transvaginally from day 15. Blastocysts were transferred on the 5th day of endometrial exposure to P (day 19). Main Outcome Measures: Blastocyst implantation rate and pregnancy rate (PR). Results: Ninety-eight percent of blastocysts survived thawing: 67 were transferred in 42 women. Eight pregnancies occurred giving a PR of 19% per ET and 11.9% per blastocyst. Conclusion: The high PR observed after transferring blastocysts on the 5th day of endometrial exposure to P in controlled E(2) and P replacement cycles speaks for a forward slide of the window of transfer in case of blastocysts.