1. Blastocyst quality affects the success of blastocyst-stage embryo transfer 
Basak Balaban, B.Sc., Bulent Urman, M.D., Aycan Sertac, Cengiz Alatas, M.D., Senai Aksoy, M.D., Ramazan Mercan, M.D. 
Fertility and Sterility 
Volume 74, Issue 2, Pages (August 2000)
DOI: /S (00)

2. Figure 1
Expanded grade 1 blastocyst on day 5 (large arrow). This embryo showed early cavitation on day 4. Arrested and degenerating embryos (small arrows).
Balaban. Blastocyst quality and embryo transfer. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )

3. Figure 2
Grade 2 blastocysts (asterisks); late developing blastocysts compared with grade 1 blastocysts. These exhibit a transitional phase before expansion. During this phase single or multiple vacuoles with sharp concave borders appear. These are usually seen starting from day 4 of development. There appears to be no morphologic difference from grade 1 blastocysts when the distinct region of the inner-cell mass and trophoectoderm have formed. Expanded grade 1 blastocysts (large arrows); early blastocysts (double arrows). Grading cannot be well distinguished between 1 and 2 until the expansion phase.
Balaban. Blastocyst quality and embryo transfer. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )

4. Figure 3
Grade 3 blastocyst. These show several degenerative foci in the inner-cell mass.
Balaban. Blastocyst quality and embryo transfer. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )

5. Figure 4
Early hatching grade 1 blastocyst (asterisks); late hatching grade 1 blastocyst (arrow).
Balaban. Blastocyst quality and embryo transfer. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )