Description

Gardner and Sakkas developed a score for evaluating the viability of a fertilized embryo based on changes seen during the first 5 days (120 hours) after in vitro fertilization. This can help determine if the embryo is suitable for implantation. The authors are from the Colorado Center for Reproductive Medicine and Yale University.


 

Times of assessment after insemination (19 assessments):

(1) 18-19 hours (6 assessments)

(2) 25-26 hours (2 assessments)

(3) 42-44 hours (3 assessments)

(4) 66-68 hours (3 assessments)

(5) 94-96 hours (2 assessments)

(6) 106-108 hours (3 assessments)

Parameter of the Fertilized Embryo

Finding

Points

size and symmetry of pronucleus at 18-19 hours

equal

10

 

not equal

0

relation of pronucleus to polar bodies at 18-19 hours

aligned

5

 

not aligned

0

cytoplasm at 18-19 hours

lacks heterogenicity and granularity

5

 

shows heterogenicity and/or granularity

0

pronucleus at 18-19 hours

both nucleolar precursor bodies polarized

10

 

both nucleolar precursor bodies not polarized

10

 

1 nuclear precursor body polarized

0

difference in the number of nucleolar precursor bodies at 18-19 hours

< 3

10

 

>= 3

0

polar bodies at 18-19 hours

not displaced from each other

10

 

displaced from each other

0

embryo at 25-26 hours

cleaved to form 2-cell embryo with even blastomeres and no fragments

15

 

has not formed a 2-cell embryo with even blastomeres and no fragments

0

zygotes at 25-26 hours

progressed to nuclear membrane breakdown

5

 

have not progressed to nuclear membrane breakdown

0

number of blastomeres at 42-44 hours

>= 4

10

 

< 4

0

fragmentation at 42-44 hours

< 20%

10

 

>= 20%

0

multinucleated blastomeres at 42-44 hours

0

5

 

>= 1

0

number of blastomeres at 66-68 hours

>= 8

10

 

< 8

0

fragmentation at 66-68 hours

< 20%

10

 

>= 20%

0

multinucleated blastomeres at 66-68 hours

0

5

 

>= 1

0

compaction at 94-96 hours

present

10

 

absent

0

blastocoele formation at 94-96 hours

present

15

 

absent

0

blastocoele cavity at 106-108 hours

full

10

 

not full

0

inner cell mass at 106-108 hours

with numerous cells tightly packed

15

 

not with numerous cells tightly packed

0

trophectoderm at 106-108 hours

many cells forming epithelium

10

 

no or few cells forming epithelium

0

 

total score =

= SUM(points for all of the findings)

 

Interpretation:

• minimum score: 0

• maximum score: 180

• The higher the score the more perfect the embryo.

 


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