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 |
Specialty: Obstetrics & Gynecology
ICD-10: ,