Embryos derived from single pronucleus are suitable for preimplantation genetic testing

Objective To study and compare preimplantation genetic testing for monogenic conditions (PGT-M) results and cycle outcomes of embryos derived from single pronucleus (1PN) versus two pronuclei (2PN). Design A retrospective cohort study from January 2018 to December 2022 involving IVF-PGT-M cycles. Subject(s) A total of 244 patients who underwent 351 IVF-PGT-M cycles. Exposure Embryo biopsy with molecular testing for a monogenic disorder. Main Outcome Measure(s) The molecular diagnosis results and clinical outcomes following the transfer of embryos derived from 1PN and 2PN in IVF-PGT-M cycles. Result(s) Embryos derived from 1PN have a significantly low developmental potential with a lower rate of embryos that underwent biopsy compared to 2PN-derived embryos; 1PN-derived embryos demonstrated a significantly lower number of blastocysts (24% versus 37.9% P<0.01) and top-quality blastocyst (22.3% versus 48.1%, P<0.01) compared to 2PN derived embryos. Lower successfully completed and unaffected PGT-M results were achieved in 1PN compared to 2PN-derived embryos (47.1% versus 65.5% and 18.7% versus 31.6%, respectively, both P<0.01), with significantly higher abnormal molecular results (39.6% versus 22.7%, P<0.01). The embryo transfer of 24 1PN-derived embryos with no affected genetic disorder resulted in five clinical pregnancies (20.8%) and four live births (16.7%). Conclusion(s) Within the limits of fewer embryos derived from 1PN that yielded unaffected embryos suitable for transfer, the clinical pregnancy and live birth rate of 1PN embryos undergoing PGT-M are reassuring. We, therefore, suggest applying PGT-M on embryos derived from 1PN embryo in order to improve the cumulative clinical pregnancy and live birth rates.