['To determine if the longer length of time that embryos donated to an anonymous couple have been frozen has a negative effect of subsequent successful pregnancy following thawing and transfer to the recipients.', 'Retrospective determination of pregnancy rates according to the length of cryopreservation time has on pregnancy outcome following transfer of embryos designated for donation.', 'Longer time of freezing did not adversely affect subsequent pregnancy rates following frozen embryo transfer.'] Are effect of the length of time that donated embryos frozen on pregnancy outcome?