BACKGROUND Cryopreservation of embryos may lead to zona hardening that may compromise in vivo hatching and implantation following thawing and transfer. Assisted hatching (AH) has been advocated as a means of assisting the natural hatching process and enhancing implantation. METHODS The aim of this study was to assess in a prospective randomized manner the effect of laser-assisted hatching (LA...

during spring, summer and winter seasons, sistani donor cows, with normal reproductive status, were superovulated and embryos were recovered non-surgically on day 7. grade a blastocyst embryos were either transferred fresh (spring) or frozen (summer and winter). recovered embryos during summer and winter were exposed to glycerol and frozen using conventional method. during spring season, recipi...

BACKGROUND Focus on the hatching process has so far been in the field of fresh embryos. Cryopreserved-thawed embryos have a lower rate of pregnancy than fresh embryos, which might be due to hardening of the zona pellucida. METHODS During a 2 year period, a prospective randomized study enrolling 253 cryopreserved-thawed cycles was performed on day 2 embryos. Pseudorandomization to assisted hat...

BACKGROUND The availability of an efficient cryopreservation program is especially important in the case of embryos that have undergone blastomere biopsy for PGD. Unfortunately, the freezing/thawing of biopsied embryos has given disappointing results when performed at the cleavage stage. In this study, embryos diagnosed as normal after PGD were grown to the blastocyst stage, frozen and thawed f...

Background: It was reported in a literature that approximately one third of the 4-cell stage embryos did not exhibit a tetrahedral shape. Non-tetrahedral embryos showed a lower in vitro developmental potential than tetrahedral embryos. Recently vitrification technology has been widely employed for embryo cryopreservation. The objective of this study was to prove our hypothesis that vitrified - ...

Canine embryos (8-cell to blastocyst stages) frozen-thawed using the slow-freezing method with glycerol (four recipients) or dimethyl sulfoxide (three recipients) as a cryoprotectant and vitrified-warmed using the Cryotop method (five recipients) were surgically transferred into the unilateral uterine horn of recipient bitches. As a result, the morphology of embryos frozen-thawed using the slow...

introduction: mouse embryos can successfully be frozen with sucrose and propandiol. however, different developmental stages of mammalian embryos have shown to have various capacities to undergo freeze-thawing procedure. in the present study, the ability of 1,2,4 and 8-ell mouse embryo to tolerate the freeze-thawing procedure was investigated and the effect of this procedure on the further in vi...

This study was designed to investigate the effect of vitrification and post-thaw survival and chromosomal aberrations caused by vitrification of vitrified 8-cell mouse embryos in comparison with a control group. To this purpose the survival rate and the frequency of chromosomal aberrations were assessed in frozen-thawed 8-cell mouse embryos after various storage durations in the presence of eth...

OBJECTIVE To assess on which day to cryopreserve and transfer thawed embryos in good-responder patients by comparing the cycle outcomes of day 3 transfers vs blastocysts formed through extended culture before or after cryopreservation. DESIGN Retrospective clinical study. SETTING Private IVF center. PATIENT(S) Frozen-thawed cycles (n = 2,531) who had ETs at day 3, 5, and 6 and post-thawed...