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

Objective: To evaluate the outcome of frozen-thawed ET using embryos previo usly 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,X X der(14;21)(q10;q10) translocation. Intervention(s): Preimplantation genetic diagnosis by polar body biopsy. Ex cess embryos were frozen using the one-step method and then thawed. Main Outcome Measure(s): Embryo survival after thawing and subsequent pregn ancy 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 f resh IVF cycle. Two normal embryos were transferred. Four normal and 3 bala nced 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 norma l (46,XX) female was delivered. Conclusion(s): Freezing and thawing of biopsied embryos resulted in a low s urvival rate. However, this should not be a deterrent to the cryopreservati on of extra chromosomally normal embryos because the embryos that do surviv e are able to implant. (C) 2000 by American Society for Reproductive Medici ne.