Gardner and Schoolcraft developed criteria for describing blastocysts. This can help select suitable blastocysts for in vitro fertilization. Better blastocysts have a better implantation success rate.
Parameters:
(1) blastocyst grade
(2) inner cell mass (ICM)
(3) trophectoderm
Blastocyst
Grade
blastocele < half of embryo volume
1
blastocele >= half of embryo volume but does not fill it
2
blastocele completely fills the embryo
3
expanded, with blastocele larger than the early embryo
4
hatching, with herniation of trophectoderm
5
hatched, completely outside zone
6
If the grade is 3 to 6, then the inner cell mass and trophoectoderm are graded.
Inner Cell Mass
Grade
many cells, tightly packed
A
several cells, loosely grouped
B
very few cells
C
Trophoectoderm
Grade
many cells, with tight knit epithelium
A
few cells
B
very few cells
C
To read more or access our algorithms and calculators, please log in or register.
