Timing embryo biopsy for PGD - before or after cryopreservation?
OBJECTIVE
Pre-implantation genetic diagnosis (PGD) is required in order to screen and diagnose embryos of patients at risk of having a genetically affected offspring. A biopsy to diagnose the genetic profile of the embryo may be performed either before or after cryopreservation. The aim of this study was to determine which biopsy timing yields higher embryo survival rates.


METHODS
Retrospective cohort study of all PGD patients in a public IVF unit between 2010 and 2013. Inclusion criteria were patients with good-quality embryos available for cryopreservation by the slow freezing method. Embryos were divided into two groups: biopsy before and biopsy after cryopreservation. The primary outcome was embryo survival rates post thawing.


RESULTS
Sixty-five patients met inclusion criteria. 145 embryos were biopsied before cryopreservation and 228 embryos were cryopreserved and biopsied after thawing. Embryo survival was significantly greater in the latter group (77% vs. 68%, p < 0.0001).


CONCLUSIONS
Cryopreservation preceding biopsy results in better embryo survival compared to biopsy before cryopreservation.
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
S
S
Shinar
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
N
N
Kornecki
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
T
T
Schwartz
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
N
N
Mey-Raz
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
H
H
Amir
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
B
B
Almog
b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.|c IVF Unit, Hillel Yaffe Medical Center , Hedera , Israel.
T
T
Shavit
a The Sarah Racine IVF Unit, Department of Gynecology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University , Tel Aviv , Israel.|b Sackler School of Medicine, Tel Aviv University , Tel Aviv , Israel , and.
J
J
Hasson
D000328:Adult; D001706:Biopsy / Q000592:standards*; D015925:Cryopreservation / Q000592:standards*; D004624:Embryo Transfer / Q000592:standards*; D005260:Female; D006801:Humans; D019836:Preimplantation Diagnosis / Q000592:standards*; D027724:Reproductive Techniques, Assisted / Q000592:standards*; D012189:Retrospective Studies; D013997:Time Factors
Biopsy; PGD; blastomere; cryopreservation; embryo; freeze; slow