Transcript Alpha Consensus 2011

Pre &Post morphological selection
of blastocysts cryopreserved with
vitrification, clinical outcomes
Tammie Roy and Steven McArthur
Embryo selection for vitrification
> Gametes and embryos can be cryopreserved at any
stage of development. The standard practice is to
cryopreserve at the blastocyst stage on day 5 or 6.
> Day 5 – All Blastocysts with intact inner cell mass and
sufficient trophectoderm.
> Day 6 – Expanding Blastocysts (or further
development) with intact inner cell mass and
sufficient trophectoderm.
Blastocyst – Grade
Blastocyst
1
– Grade 2
Grade 1 – Gardner Equivalence
Grade 2 – Gardner Equivalence
2AA, 3AA, 4AA, 5AA, 6AA
1AA, 2AB, 2BA, 2BB, 3AB, 3BA, 3BB,
4AB, 4BA, 4BB, 5AB, 5BA, 5BB, 6AB,
6BA, 6BB
Blastocysts were vitrified using modified Kitazato
Cryotop protocol
60-90 sec
9-15min
(8% DMSO + EG)
(16% DMSO + EG,
0.6M trehalose)
a)
b)
c)
d)
e)
f)
Different stages of the PGD (a,b,c) and non-PGD (d,e,f) freeze
(a, d) at thaw (b, e) and 24 hours post-thaw (c, f).
More grade 1 blastocysts transferred as fresh, more grade
2 blastocysts remaining to be vitrified
p<0.05
Similar implantation rates with comparable
quality fresh and vitrified blastocysts
100%
Fresh
years
<>=38
38 years
Vitrified
p<0.05
*
p<0.05
*
*
24% 43%
24% 44%
*
52%
59%
46%63%
41%
49%
33% 54%
50%
0%
TOTAL
Grade 1
Grade 2
Embryo developmental stage has some impact
on implantation rates for both fresh and vitrified
100%
EB
B
XB
HB
p<0.05
*
50%
56%
65%
43%
48%
48%
43%
25%
50%
*
0%
Fresh
n=
16
4
51 29
233 105
193 82
Vitrified
Vitrification post blastocyst biopsy
Total Number Total Number
Embryos
Embryos
Thawed
Survived
PGD
% survived
Average
Implantation
Number of
rate (Fetal
Embryos
heart per
Transferred per
embryo
ET
transferred)
<38
26
26
100%
1.04
50.0%
>=38
12
11
92%
1.10
27.3%
Total
38
37
97%
1.06
43.2%
Conclusion
> Whilst blastocyst development and grade on day 5
impacts positively on implantation rates, subsequent
cryopreservation by vitrification does not
significantly reduce implantation rates. Reliable
vitrification and morphology assessment methods
allow single blastocyst embryo transfer to be
successfully implemented for women.