This paper provides a concise review of single embryo transfer (SET) in cycles using fresh embryos as well as in cycles using frozen-thawed embryos. Relevant studies were identified by a computerized search in PubMed for the period 1995-2004. The pregnancy rates, delivery rates and multiple pregnancy/birth rates were evaluated after fresh or frozen embryo transfer as well as cumulative delivery...

Background The purpose was to investigate the effect of the duration of gamete incubation on fertilization rate, embryo cleavage, and embryo quality before and after freezing in mice. MaterialsAndMethods Ovulated oocytes collected from superovulated mice after ip injection of PMSG and hCG were divided randomly into control and experimental groups. Oocytes from the control group were inseminated...

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...

BACKGROUND To determine whether mouse embryos generated from frozen-thawed oocytes can successfully survive a second cryopreservation. METHODS Immature C57BL6*BALB/c female mice underwent superovulation and the collected oocytes were divided into three groups. Group A oocytes (n = 107) underwent IVF. Group B oocytes (n = 167) underwent IVF and embryos generated were then cryopreserved. Group ...

When frozen embryos are publically debated in the United States, they are most often positioned as having two possible future trajectories: (1) as individual humans and (2) as contributors to stem cell research. Long-term embryo accumulation threatens both of these futures. An accumulated embryo is stuck in a clinic, held back from having an individual future or from contributing to science. Th...

Two flocks of ewes were used as sources of embryos for embryo transfer programs: a Merino flock comprising 3 lines differentially selected on weaning weight and a Coopworth flock consisting of three lines differentially selected for backfat thickness. Effects of embryo genotype, year of transfer, sire and number of embryos transferred on embryo survival were examined. No significant line or sir...

Continuous improvements to assisted reproductive technology (ART) have facilitated the advancement and preservation of animal genetics as well as animal reproductive efficiency. One of the ART techniques is cryopreservation which facilitates embryo transfer procedures. In the present experiment embryos produced in vivo or in vitro were transferred to the recipient ewes just after collection (fr...

Mares can be artificially inseminated with chilled or frozen semen to increase the revenue from their offspring. Embryo transfer can be used to produce more than one foal from a single mare per season. Recent advances in using equine follicle-stimulating hormone to induce superovulation in mares have stimulated research on preserving equine embryos. Equine embryos are usually collected on day 7...