Morphokinetic differences on embryo development after normal or abnormal fertilization

Could monopronucleated ICSI zygotes be considered for transfer? Analysis through time-lapse monitoring and PGS

“…The presence of 2PB was also clearly established to avoid the inclusion of diploid embryos resulting from the nonextrusion of the second polar body. Timings for second PB extrusion and PN appearance are similar to those observed in 2PN zygotes [19]. According to the images obtained, our hypothesis is that the origin of the monopronucleated zygotes could be due to either a parthenogenetic oocyte activation or to an abnormal formation of the nuclear envelope.…”

Morphokinetics and in vitro developmental potential of monopronucleated ICSI zygotes until the blastocyst stage

“…Although it only represents 2-5% of intracytoplasmic sperm injection (ICSI) zygotes (Staessen and Van Steirteghem, 1997;Itoi et al, 2015;Bradley et al, 2017;Mateo et al, 2017), it is still interesting to study this pattern. Preliminary TL studies have assessed monopronucleated zygotes (1PN), generally focusing on the fertilization process and early development (Boada et al, 2012;Yamaguchi et al, 2013;Igashira et al, 2016;Tanaka et al, 2016;Araki et al, 2018). Using this technology, some authors have been able to detect a novel mechanism of 1PN formation involving the complete extrusion of female genetic material in a third polar body-like cell (Mio et al, 2014;Iwata and Mio, 2016).…”