Aneuploidy does not Correlate with Cell Number on Day 3

Leigh WHITMAN1, Jeremy OSBORN2, Jacquelyn IRVING1, Keith HARRISON1

1 Queensland Fertility Group, Brisbane, Australia2 Queensland Fertility Group, Toowoomba, Australia

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Background

Patients undergoing PGD for Aneuploidy screening with QFG have the option of either having a Day 3 biopsy with the intention of a fresh transfer on Day 5 or a Day 5 biopsy and freeze all.

Patients planning a Day 3 biopsy often query the likelihood of having an embryo identified as being suitable for transfer following testing if they only have a few embryos or if the embryos are developing slowly.

To provide patients with the relevant information, a review of Day 3 embryo quality and PGD results was undertaken.

Methods

Retrospective review of embryo quality on Day 3 for cases where Array PGD was undertaken using the 24 sure® (illumina) platform.

Data Set

• 63 cycles

• 45 patients

• 29 to 44 years

• 360 embryos biopsied either Day 3 or Day 5 post oocyte collection

• Grading on Day 3 post oocyte collection

Results

The biopsy of 360 embryos from 63 PGD cycles for 47 patients resulted in informative PGD results for 355 embryos (98.6%).

Patient’s age at the time of biopsy ranged from 29 to 44 years, with a mean of 36.0 years.

73 embryos had No Abnormality Detected (NAD; 20.5%), whilst 62 (17.5%) had a complex aneuploidy.

At the time of biopsy, embryo cell number ranged from 5 to 16 cells on Day 3, with 137 embryos (38.6%) at the 8 cell stage.

Quality grades also varied between embryos, however the majority of embryos (74%) were graded good to excellent.

Results by Cell Stage on Day 3

Cell Stage on Day 3

No Abnormality

Detected (NAD)

Aneuploidy Detected

Total number of embryos % NAD

5 3 11 14 21.46 16 79 95 16.87 12 69 81 14.88 31 106 137 22.69 2 12 14 12.3

10 4 5 9 44.411 1 2 3 33.312 2 2 4 5013 0 0 0 - 14 0 2 2 015 0 0 0 - 16 0 1 1 0

Results by Quality Grade on Day 3

Quality Grade on Day 3

No Abnormality

Detected (NAD)

Aneuploidy Detected

Total number of embryos % NAD

1 0 2 2 0

2 8 47 55 14.5

3 42 167 209 20.1

4 14 41 54 25.9

5 0 1 1 0

C 9 30 39 23.1

Grading: 5 highest, 1 lowest C = compacting

Results

A comparison of the embryo cell stage and quality grading with the PGD results, showed no significant increase in the likelihood of an embryo being identified as NAD.

Statistical analysis undertaken using Chi-Square (with significance at P <<0.05)

For example;

5 to 7 cell stage vs 8 cell stage – P = 0.159 to 16 cell stage vs 8 cell stage – P = 0.57

Quality grade 2 vs Quality grade 4 – P = 0.15Quality grade 3 vs Quality grade 4 – P = 0.39

Conclusions

Embryos with low cell numbers or poor quality on day 3 do not show an increased incidence of aneuploidy.

Acknowledgements

Grading of embryos undertaken by all scientists within the Queensland Fertility Group Brisbane laboratory

24 sure® (illumina) testing undertaken by scientists within the Melbourne IVF, Preimplantation Genetics Laboratory