Embryo selection is based on several morphological criteria, including:  

- Cell number and developmental stage (Day 2, 3, or 5).  

- Blastocyst structure, including the number and appearance of cells and the degree of fragmentation.  

Embryologists grade embryos based on these factors to identify the best candidates for transfer. Embryo development is monitored every 24 hours, though many clinics now focus only on development between Day 1 and Day 5, when the transfer occurs.  

 Does Embryo Grading Guarantee Pregnancy?  

No, embryo grading does not predict pregnancy with certainty. While the system helps assess implantation potential, it is not an absolute quality marker:  

- Morphologically "perfect" embryos can have genetic abnormalities and may not result in pregnancy.  

- Less visually ideal embryos may have strong genetic potential, leading to a successful pregnancy and a healthy baby.  

 Is Embryo Development in the Lab as Effective as in the Uterus?  

Yes, with advancements in culture conditions, research now suggests that embryo development in the laboratory is just as effective as in the uterus up to the blastocyst stage.