Effect of Group Embryo Culture under Low-Oxygen Tension in Benchtop Incubators on Human Embryo Culture: Prospective, Randomized, Controlled Trial

Improving Embryo Quality by Strictly Controlling IVF Laboratory Environment

“…In regard to embryonic parameters, Ebner et al [52] prospectively studied the effect of individual or group embryonic culture and showed that the group culture strategy was superior in terms of compaction, development and quality of blastocysts; and Tao et al [53] evaluated the influence of the same culture strategy but grouping embryos after day 3 according on embryo quality, showing that culturing embryos in group promoted blastocyst development and blastocyst utilization rate compared to those embryos individually cultured. Similar results were observed by Ruíz et al [47], Glatthorn et al [54], and García-Ferreyra,…”

“…It is important to highlight that in vivo, early embryonic development occurs in the absence of signalling factors because mammalian zygotes develop to the blastocysts stage free-floating in a dynamic fluid environment and without direct cell to cell contact; however, Lonergan [44] and O´Neill et al [45] suggested that signaling factors are necessary to modulate cell growth and cell division, or have anti-apoptotic functions, during preimplantation embryo development in vivo. When embryos are cultured in group, developmental rates and embryo quality are improved compared to those embryos individually cultured [46,47], and this beneficial nature is related to embryotrophic factors that support or promote their development in vitro, such as insulin-like growth factor-I [48], insulin-like factor-II [49], platelet-activating factor (PAF) [50], phospholipase C (PLC), protein kinase B/Akt, and 3-phosphoinositide-dependent kinase 1 (PDKS1) [51]. Cultured embryos in group produce and release trophic factors that act on the embryo itself and neighboring embryos through paracrine/autocrine actions improving their development, quality, and their implantation probability in the uterus [50].…”

“…With regard to clinical outcomes of group and individual strategies, some studies (Ebner et al [52], Tao et al [53], and Glatthorn et al [54] did not observed significant differences in the pregnancy and implantation rates between group and individual culture. However, Ruíz et al [47] carried out a prospective study to evaluate the effectiveness of group embryo culture using undergoing IVF one hundred forty-eight women data and the result showed a significantly higher implantation rate and live birth delivery rate with the first fresh embryo transfer. Our team used donor oocytes cycles to analyze the effect of group culture on embryo development and clinical outcomes and our results showed significantly more blastocysts, higher pregnancy, implantation ans live birth rates and lower miscarriage rates compared to individual culture ( At present, most laboratories worldwide using the individual embryo culture method as a manner to assess the embryo development and principally induced by the freeze-all and PGT-A practice, nonetheless this strategy has a detrimental impact on some embryonic parameters and inclusive on clinical outcomes as has been shown by several authors.…”

Redox Regulation and Oxidative Stress in Mammalian Oocytes and Embryos Developed In Vivo and In Vitro

“…Given that 21% (atmospheric) O 2 results in increased ROS, many IVF clinics have switched to low-O 2 incubators to more closely mimic O 2 concentrations of 2-8% in the reproductive tract [63,65]. Several clinical trials have been carried out to determine the impact of low concentrations of O 2 on various parameters of fertility [226][227][228]. Culture of embryos in 5% O 2 increases the percentage developing to the blastocyst stage and their quality.…”

“…Culture of embryos in 5% O 2 increases the percentage developing to the blastocyst stage and their quality. However, there is limited evidence to show low O 2 improves live-birth rate [226][227][228]. Table 2.…”