Strictly selected Mono- and non-pronuclear blastocysts could result in appreciable clinical outcomes in IVF cycles

The aim of the study was to examine the clinical value of blastocysts derived from mono-pronuclear (1PN) or non-pronuclear (0PN) zygotes with two polar bodies (2PB), which were selected by our criteria. We retrospectively analysed 610 frozen-thawed blastocyst transfer (FET) cycles and the corresponding oocyte retrieval cycles from 2014 to 2017. Developmental potential and clinical outcomes of embryos derived from zygotes with various numbers of pronuclei were analysed. Based on more detailed pre-selection settings, blastulation rates of 1PN/2PB and 0PN/2PB-derived embryos were 70.18% and 69.17%, respectively. Blastocyst FET results were not significantly different between 2PN/2PB, 1PN/2PB and 0PN/2PB groups in terms of clinical pregnancy rates (59.79%, 47.06% and 56.25%), implantation rates (47.24%, 40.00% and 47.62%), live birth rates (49.39%, 29.41% and 43.75%) or malformation rates (0%, 0% and 0%). In conclusion, after strict morphological selection and blastocyst culture, 1PN/2PB and 0PN/2PB-derived embryos in IVF cycles can have considerable clinical value. Blastocysts derived from 1PN/2PB or 0PN/2PB zygotes are worthwhile FET option for patients who have no available 2PN-derived embryos.