Preimplantation aneuploid embryos undergo self-correction in correlation with their developmental potential.
OBJECTIVE
To investigate the incidence of embryos' self-correction during preimplantation development in terms of mosaicism and in correlation with its developmental stage.


METHODS
Prospective study to compare the chromosome status of embryos on day 3 with that of day 5, in correlation with their developmental stage.


METHODS
In vitro fertilization unit of a university-affiliated hospital.


METHODS
Eighty-three aneuploid embryos.


METHODS
Fluorescence in situ hybridization (FISH) reanalysis.


METHODS
Day 3 embryos classified as mosaic or chromosomally abnormal by preimplantation genetic screening (PGS) were reanalyzed on day 5. The results were evaluated in correlation with the embryos' developmental stage.


RESULTS
Out of 83 day 3 aneuploid embryos, 15 (18.1%) were diagnosed with mosaicism. The FISH reanalysis on day 5 demonstrated that 27 embryos (32.6%) were partly or entirely normal disomic. Of these 83 aneuploid embryos, 8 (9.7%) underwent complete self-correction. The PGS results demonstrated that 26.5% of the embryos were trisomic, of which 41.0% underwent trisomic rescue by day 5. Self-correction was in correlation with the embryo's developmental stage, i.e., 38.1% of aneuploid embryos that developed to the blastocyst stage underwent self-correction compared with only 12.5% of embryos that only cleaved after biopsy.


CONCLUSIONS
Our results demonstrate that self-correction of aneuploid and mosaic embryos occurs probably more significantly during development toward the blastocyst stage than in delayed embryos. In addition, trisomic embryos correct themselves more than other aneuploidies. These findings suggest that PGS results must be interpreted with caution.
Barbash-Hazan
Shiri
S
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Frumkin
Tsvia
T
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Malcov
Mira
M
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Yaron
Yuval
Y
Prenatal Diagnosis Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Cohen
Tania
T
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Azem
Foad
F
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Amit
Ami
A
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Ben-Yosef
Dalit
D
Racine IVF Unit, Genetic Institute, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address: dalitb@tasmc.health.gov.il.
D000328:Adult; D000782:Aneuploidy; D001706:Biopsy; D001755:Blastocyst / Q000473:pathology / Q000502:physiology*; D020732:Cytogenetic Analysis / Q000379:methods; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D011247:Pregnancy; D019836:Preimplantation Diagnosis; D011379:Prognosis; D011446:Prospective Studies