Prolonged cultivation of embryos to the blastocyst stage has become a routine practice in the human in vitro fertilization program (IVF) since 1999, when the first commercial sequential media were developed. The culture systems have been improved many times and today most of the blastocyst culture media enable the embryos to reach the blastocyst stage in more than 50% of cases (Gardner et al., ...

The first differentiative event in mammalian development is segregation of the inner cell mass and trophectoderm (TE) lineages. The epithelial TE cells pump fluid into the spherical blastocyst to form the blastocyst cavity. This activity is fuelled by glucose supplied through facilitative glucose transporters. However, the reported kinetic characteristics of blastocyst glucose transport are inc...

The nature of the early interaction between blastocyst and endometrial epithelium is known to be highly specific within individual species. Despite this unique initial interaction, the trophoblast promptly establishes a common theme as invasive cells penetrate the endometrium and colonize its local blood vessels. In all animals with this type of implantation the blastocyst plays a more active r...

background: embryo cryopreservation is the process that water is removed from the cell by cryoprotectant materials, and embryos are stored at temperature below zero. this process may affect the viability and developmental potential of embryos. objective: in this study, the effect of the vitrification cryotop method on the expression level of oct4 and mest developmental genes in mouse blastocyst...

Mammalian embryonic diapause is a phenomenon defined by the temporary arrest in blastocyst growth and metabolic activity within the uterus which synchronously becomes quiescent to blastocyst activation and implantation. This reproductive strategy temporally uncouples conception from parturition until environmental or maternal conditions are favourable for the survival of the mother and newborn....

Two independent studies have recently suggested similar models in which the embryonic and abembryonic parts of the mouse blastocyst become separated already by the first cleavage division. However, no lineage tracing studies carried out so far on early embryos provide the support for such a hypothesis. Thus, to re-examine the fate of blastomeres of the two-cell mouse embryo, we have undertaken ...

BACKGROUND Embryo quality may be accurately assessed as early as the pronuclear zygote phase, as shown in recent studies. However, it is not known whether good quality zygotes are destined to become good quality cleavage stage embryos and blastocysts. METHODS In this retrospective study, 86 intracytoplasmic sperm injection-embryo transfer cycles were studied where each available embryo was sc...

The mammalian embryo is encased in a glycoproteinaceous coat, the zona pellucida (ZP) during preimplantation development. Prior to implantation, the blastocyst must undergo 'hatching' or ZP escape. In hamsters, there is a thinning of the ZP followed by a focal lysis and a complete dissolution of the ZP during blastocyst hatching. Earlier studies from our laboratory have indicated a role for cys...

BACKGROUND Several studies have evaluated outcomes of singleton pregnancies after blastocyst versus cleavage stage embryo transfer. Higher incidences of preterm birth (PTB), very preterm birth (VPTB), low birthweight (LBW) and congenital malformations were identified in a few of them. The objective of our study was to systematically review and meta-analyze pregnancy and neonatal outcomes among ...