Blastocyst conversion rate and ploidy in patients with structural rearrangements.

Objective: The primary objective of this study was to test the hypotheses that compared to IVF cycles undergoing preimplantation genetic testing for aneuploidy (PGT-A) with or without testing for monogenic disorders (PGT-M), IVF cycles undergoing PGT for structural rearrangements (PGT-SR) will have (1) a poorer blastocyst conversion rate and (2) fewer usable blastocysts available for transfer. Secondarily, the study aimed to compare pregnancy outcomes among PGT groups.
Patients: Retrospective cohort study including cycles started from January 1, 2012, to March 30, 2020, with the intent of pursuing PGT-A, PGT-A with PGT-M, and PGT-SR, with trophectoderm biopsy on days 5 or 6.
Results: A total of 658 women underwent 902 cycles, including 607 PGT-A, 216 PGT-A&M, and 79 PGT-SR cycles. When compared with the blastocyst conversion rate for the PGT-A group (59.4%), and after adjustment for patient age, total number of mature oocytes, BMI, and ICSI, there were no significant differences for either the PGT-A&M (69.7%, aRR 1.03, 95% CI 0.96-1.10) or PGT-SR (63.2%, aRR1.04, 95% CI 0.96-1.13) groups. Compared to the PGT-A group, the proportion of usable blastocysts was statistically significantly lower in the PGT-SR group: 35.1% versus 24.4% (aRR 0.57, 95% CI 0.46-0.71) and the PGT-A&M group: 35.1% versus 31.5% (aRR 0.68, 95% CI 0.58-0.81). Implantation, pregnancy, and miscarriage rates were equivalent for all groups.
Conclusion: Patients with structural rearrangements have similar blastocyst development but significantly fewer usable blastocysts available for transfer compared to PGT-A testers. Nevertheless, with the transfer of a usable embryo, PGT-SR testers perform as well as those testing for PGT-A.