The effect of timing of embryonic progression on chromosomal abnormality.
OBJECTIVE
To evaluate the relationship between aneuploidy and timing of blastocyst formation.


METHODS
Historical cohort study.


METHODS
Private IVF clinic.


METHODS
Ninety-four couples undergoing IVF treatment in combination with chromosomal screening of embryos. The mean maternal age was 39.2 years and average number of embryos per patient 5.3.


METHODS
A total of 530 embryos were biopsied on day 3 and underwent chromosome screening with microarray-based comparative genomic hybridization.


METHODS
Effect of day of embryo blastulation and morphologic grade on aneuploidy rate.


RESULTS
Day 5 morulas that progressed to blastocysts on day 6 were significantly less likely to be aneuploid (79.8%) than day 5 morulas that did not progress to blastocysts (92.9%). However, there was no significant difference in aneuploidy rates when embryos that became blastocysts on day 5 were directly compared with embryos that became blastocysts on day 6.


CONCLUSIONS
Delayed blastulation is not associated with increased aneuploidy rates, but absence of blastulation is associated with increased aneuploidy. Therefore, we conclude that when choosing a morula for transfer on day 5, there may be a benefit in waiting an extra day for the possibility of blastulation to occur.
Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of California, Los Angeles, California 90095, USA.
Lindsay
L
Kroener
Gayane
G
Ambartsumyan
Christine
C
Briton-Jones
Daniel
D
Dumesic
Mark
M
Surrey
Santiago
S
Munné
David
D
Hill
D000328:Adult; D000782:Aneuploidy; D001755:Blastocyst / Q000166:cytology* / Q000502:physiology*; D002869:Chromosome Aberrations; D015331:Cohort Studies; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009028:Morula / Q000166:cytology / Q000502:physiology; D011247:Pregnancy; D018873:Pregnancy Rate; D019836:Preimplantation Diagnosis / Q000379:methods*; D013997:Time Factors