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Fertility and Sterility, The Official Journal of the American Society
of Reproductive Medicine
Volume 82, Issue (Supplement 2), Page S246 (September 2004)
Outcome of preimplantation genetic diagnosis in frozen-thawed embryos
J.Y. Kim, C.K. Lim, J.H. Jun, H.S. Lee, M.K. Koong, I.S. Kang
Objective
Cryopreservation of embryos is widely applied in ART. And it is also useful
for efficient preimplantation genetic diagnosis (PGD) in cases with supernumerary
embryos or with collected embryos through several cycles in poor responders.
The aim of this study is to evaluate the feasibility of FISH or PCR in
the blastomeres biopsied from frozen-thawed embryos and the outcome of
PGD, and to determine whether frozen- thawing process affect the embryo
development after blastomere biopsy.
Design
Retrospective clinical study.
Materials and methods
In 86 patients, 319 PGD cycles were performed between Jan. 2000 and Dec.
2003. Patients were divided into 2 groups: thawed PGD group - PGD cycle
was performed in frozen-thawed embryos (33 patients, 40 cycles, age =
34.2±4.7yrs. (mean±SD)), fresh PGD group - PGD cycle was
performed in fresh embryos (patients=53, cycles=279, mean age = 31.8±4.3yrs.).
In 20 cycles, supernumerary embryos were frozen and thawed, and in 19
cycles, embryos were collected through several cycles in poor responders
and then thawed altogether. PGD was performed for translocation carriers
or aneuploidy screening and some single gene diseases were included. Ovarian
stimulation was done using GnRH agonist/FSH long protocol or clomifen
citrate/GnRH antagonist protocol in poor responders. Oocytes were inseminated
by ICSI and the fertilized embryos were cryopreserved at PN stage or cleaving
embryo stage. In thawed embryo transfer cycles, estradiol was administrated
from day 2 of menstrual cycle and progesterone injection was started from
1 day before 2PN thawing. The cryopreserved embryos were thawed and blastomeres
were biopsied in survived embryos developed to 6–10 cell stage. PGD
was performed by using FISH or PCR and the embryos were replaced 3 days
after PN thawing. The survival rate of the thawed embryos, the rate of
successful diagnosis for FISH or PCR, embryo development and pregnancy
rate were compared between thawed and fresh PGD cycles.
Results
The survival rate of thawed embryos was 71.2±29.8% (mean±SD).
The FISH or PCR analysis was successful in 88.1±22.0 % in thawed
PGD group and 95.2±10.3% in fresh PGD group (P>0.05). The proportion
of transferable embryos in thawed PGD group was similar to fresh PGD group
(21.6±19.7% vs. 27.4±18.8%; P>0.05). The rate of embryos
developed cleavage after biopsy was also similar in both groups (62.0±26.5%
vs. 66.4±26.1%; P>0.05). The clinical pregnancy rate per transfer
was 11.4 % (4/35) in thawed PGD group and 21.3% (57/267) in fresh PGD
group. Although it was not statistically significant, the pregnancy rate
tends to be lower in thawed PGD group.
Conclusion
Our data suggest that blastomere biopsy and analysis with FISH or PCR
is feasible in frozen-thawed embryos if the embryos survive well. The
embryo development was not affected by biopsy in thawed embryos, but the
pregnancy rate was lower in thawed PGD cycles. Therefore PGD in thawed
embryos could be applied usefully in cycles with supernumerary embryos
or collected cyropreserved embryos, and optimization of freezing-thawing
condition might be important.
Dept. of Ob/Gyn, Samsung Cheil Hospital, Sungkyunkwan Univ.School of
Medicine, Seoul, Republic of Korea; Lab. of Reproductive Biology and Infertility,
Samsung Cheil Hospital, Seoul, Republic of Korea
Supported by: None.
PII: S0015-0282(04)01955-7
doi:10.1016/j.fertnstert.2004.07.655
© 2004 Published by Elsevier Inc.
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