enrollment too slow, too many variables included in the study

This randomized pilot study will assess if there is a difference in clinical pregnancies using donor oocytes cryopreserved in either a closed or a semi-closed vitrification device.

Oocyte cryopreservation was optimized by the use of a new technique: vitrification. Vitrification can be performed using either open devices (where the oocytes are in direct contact with the liquid nitrogen) or closed systems (where the oocytes are never in contact with liquid nitrogen). Previous studies have associated the use of open devices to higher oocyte survival rates and better embryo development. However, any beneficial effect on clinical pregnancy rates is yet to be proven. Hence, the objective of this study is to compare the clinical pregnancy rates of open and closed oocyte vitrification devices.

Inclusion Criteria:

• this is a pragmatic randomized clinical trial. Hence, all consenting oocyte recipients will be eligible for the study

Exclusion Criteria:

• women who do not consent or that cannot comprehend the investigational nature of the study