Reduced blastocyst formation in reduced culture volume

Abstract

Purpose The aim of this prospective sibling oocyte study was to evaluate whether reduced culture volume improves blastocyst formation. Methods Twenty-three patients with extended embryo culture until day 5 were selected for the study. After injection, 345 sibling oocytes were individually cultured in either 25 or 7 μl droplets of Origio cleavage medium under oil. On day 3 of development, embryos were transferred to droplets with the corresponding volume of Origio blastocyst culture medium. Fertilization and embryo quality on day 3 and day 5/6 were evaluated. Results No statistically significant difference (p=0.326) in fertilization rate was observed (81.3 versus 83.0 %). There was no significant difference in terms of the number of excellent and good-quality embryos obtained on day 3 between both groups (p=0.655). Embryo culture in 25 μl droplets led to more embryos with a higher cell number when compared to 7 μl culture (p=0.024). On day 3, 132 and 131 embryos were considered for further culture until day 5/6. Blastulation rates were significantly higher in the 25 μl group (75.0 versus 61.6 %; p=0.017) and significantly more day 5 embryos with excellent and good quality were found in this group (54.5 versus 40.5 %; p=0.026). Finally, the utilization rates expressed per mature oocyte (41.4 versus 29.8 %; p=0.043), per fertilized oocyte (50.7 versus 36.6 %; p=0.023), and per day 3 embryo undergoing extended culture to day 5/6 (54.5 versus 39.7 %; p=0.019) were all significantly higher in the 25 μl group. Conclusion Reduced culture volume (7 μl) negatively impacts early development by reducing the cell number on day 3 and both blastocyst formation and quality.

The Effect of Dose Adjustments in a Subsequent Cycle of Women With Suboptimal Response Following Conventional Ovarian Stimulation

“…Secondary endpoint was the total number of good quality Day 3 embryos between cycles. EQ was classified similar to what is described in a previous study performed by De Munck et al ( 6 ), with a minor update in the classification (good quality embryos included up to <50% fragmentation).…”

In vitro culture of individual mouse preimplantation embryos: the role of embryo density, microwells, oxygen, timing and conditioned media

“…Embryo density during single embryo culture can have a dramatic effect on cell numbers, as well as cleavage, blastocyst and hatching rates in the mouse (Lane and Gardner, 1992;Melin et al, 2009;O'Neill, 1997;Paria and Dey, 1990). In humans, one study observed no effect of embryo density on blastocyst rate (Rijnders and Jansen, 1999), but evidence from two recent studies show that embryo density is an important factor in human blastocyst development, although their conclusions on optimal density were inconsistent (De Munck et al, 2015;Minasi et al, 2015). The beneficial effect of increasing embryo density may be explained by the concentration of autocrine factors in the media.…”

Impact of the IVF laboratory environment on human preimplantation embryo phenotype

“…One study found no effect of altering the media volume from day 3 to 5; 205 however, a more recent study found that reducing the media volume for the entire duration of culture resulted in a higher blastocyst rate, 211 and yet another study reported the reverse, that is reduced media volume resulted in a lower blastocyst rate. 212 These contradictory results are probably because optimum embryo density is dependent on other culture conditions, including oxygen, 97,198,199,[213][214][215] which suggests that individual clinics will need to optimize embryo density for their culture system.…”