Human embryo fragmentation in vitro and its implications for pregnancy and implantation

Embryo selection criteria based on morphology VERSUS the expression of a biochemical marker (sHLA-G) and a graduated embryo score: prediction of pregnancy outcome

“…Determining which morphologic evaluation system [10][11][12][13] to use for transferring embryos on Day 2/3, and to achieve pregnancy rates similar to embryos that are transferred at the blastocyst stage, is a controversial subject [14,15]. Some researchers claimed that transferring selected embryos on day 3 yielded a pregnancy rate equivalent to embryos transferred on day 5 or 6 [16,17].…”

An oocyte score for use in assisted reproduction

“…This is usually achieved either by the extended culture of human embryos to the blastocyst stage [5,6] or by the morphological analysis and selection of the highest quality embryos for transfer [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. More recently, the assessment of zygote quality has been applied [23][24][25][26][27][28][29][30][31][32].…”

Selection of Embryos for Day-3 Transfer at the Pronuclear-Stage and Pronuclear-Stage Cryopreservation Results in High Delivery Rates in Fresh and Frozen Cycles

“…Several oocyte, zygote, and cleavage-stage grading methods that were not used in this study have been shown to correlate with an embryo's implantation potential (1)(2)(3)(5)(6)(7)11,12,28,(30)(31)(32)(33)(34)(35)(36)(37). Tesarik et al (1) showed that the relationship between the number of embryos transferred and the multiple rate depended on PN-S morphology; transfer of 2 embryos from pattern zero zygotes usually resulted in a twin pregnancy.…”

“…New methods under evaluation include number, pattern, and distribution of nucleoli within the PN (1,2,5,7), size and shape of PN-S halos (7), early cleavage to the 2-cell stage (32,36,37), day-3 fragmentation pattern (35), and variation in the thickness of the zona pellucida.…”