Pregnancy following transfer of ooplasm from cryopreserved-thawed donor oocytes into recipient oocytes.

OBJECTIVE

To determine if frozen-thawed donor oocytes could be used to provide cytoplasm for transfer into patients' oocytes to improve subsequent embryonic development.

DESIGN

Prospective evaluation of the procedure in consenting IVF patients.

SETTING

Assisted reproductive technology program.

PATIENT(S): The study was open to consenting IVF patients (of any age) with a history of poor embryo quality or those couples in which the wife's age was > or = 40 years.

INTERVENTION(S): Transfer of donor egg cytoplasm from frozen-thawed oocytes into the oocytes of infertile recipients.

MAIN OUTCOME MEASURE(S): Donor oocyte survival following cryopreservation, fertilization following cytoplasmic transfer into recipient oocytes, embryo quality, and pregnancy outcome.

RESULT(S): Oocytes collected from four donors were cryopreserved and 61% (28/46) survived the thaw procedure. Cytoplasmic transfer was performed on the eggs of four patients, with fertilization occurring in 70.3% (26/37). Twin pregnancy was established in one patient (35 years of age) with a history of poor embryo quality.

CONCLUSION(S): Cryopreserved donor oocytes may provide a source of cytoplasm for transfer into recipient oocytes, eliminating the need for cycle synchronization between donor and infertile patient.