Pregnancy after polar body biopsy and freezing and thawing of human embryos.

OBJECTIVE To evaluate the outcome of frozen-thawed ET using embryos previously biopsied for preimplantation genetic diagnosis during a fresh ET cycle. DESIGN Prospective evaluation. SETTING Assisted reproductive biology program. PATIENT(S) A 31-year-old, G4, P1, TAB1, SAB2 carrier of a balanced RT 45,XX der(14;21)(q10;q10) translocation. INTERVENTION(S) Preimplantation genetic diagnosis by polar body biopsy. Excess embryos were frozen using the one-step method and then thawed. MAIN OUTCOME MEASURE(S) Embryo survival after thawing and subsequent pregnancy outcome. RESULT(S) Among the 32 mature oocytes, the results of fluorescence in situ hybridization were available for 25 polar bodies. Eleven were unbalanced, 10 were normal (8 fertilized), and 4 were balanced (3 fertilized) for the fresh IVF cycle. Two normal embryos were transferred. Four normal and 3 balanced embryos were cryopreserved. A chemical pregnancy resulted. Four months later, the 7 cryopreserved embryos were thawed; 2 survived (1 balanced and 1 normal) and were transferred. An ongoing pregnancy resulted, and a normal (46,XX) female was delivered. CONCLUSION(S) Freezing and thawing of biopsied embryos resulted in a low survival rate. However, this should not be a deterrent to the cryopreservation of extra chromosomally normal embryos because the embryos that do survive are able to implant.