PGT-A in POSEIDON Patients - perspectives and limitations.

Objective: The aim of this study was to determine the likelihood of being able to perform PGT-A, and its results, in each POSEIDON group compared to their age-matched non-POSEIDON group.

Methods: This was a retrospective study of 4 groups of POSEIDON patients (n=824) who underwent intracytoplasmic sperm injection (ICSI) The controls were non-POSEIDON patients in two age groups (<35 and ≥35 years old; n=360).

Results: The non-POSEIDON <35Y group had the highest number of embryos at the blastocyst stage that could be used for PGT-A (5.1±2/cycle), and the POSEIDON IV group had the fewest (0.6±0.3/cycle). Significantly fewer blastocysts were PGT-A tested in the groups with no indications for PGT-A (i.e. POSEIDON I (26%) and III (28%) and non-POSEIDON <35Y (39%)), compared to the groups with indications (i.e. POSEIDON II (69%), and IV (67%) and non POSEIDON ≥35Y (72%)). The euploidy rate was similar between groups without PGT-A indications (59%-64%) and between groups with indications (35-41%), but was significantly lower in groups with indications (p<0.001).

Conclusions: POSEIDON patients are as willing to undergo PGT-A testing as non-POSEIDON patients, despite the poor prognosis. However, the final PGT-A result is very low compared to that in non-POSEIDON patients of the same age. Failure is usually caused by the inability to perform the blastocyst biopsy due to a lack of oocytes or blastocyst-stage embryos, and to a low rate of euploidy in groups ≥35Y.