Effect of reduced oxygen concentrations on the outcome of in vitro fertilization

The effect of two distinct levels of oxygen concentration on embryo development in a sibling oocyte study

“…It emerged that the fertilization and cleavage rates in our series were not influenced by the changes in oxygen concentration. This coincides with the findings of other studies [1,4,7,15,17,27]. However, the number of blastomeres on day 3 was significantly higher in the current study when the 5 % O 2 concentration was used compared with the 20 % concentration.…”

“…The current study showed significantly more day 3 topquality embryos with the low oxygen concentration regimen. These data are consistent with those of Bahçeci et al [1], Ciray et al [5] and Kea et al [15] who also found better quality embryos when using a lower (5 %) oxygen concentration. Since top-quality embryos were more abundant in our 5 % O 2 group, 76 transferred embryos came from this group, significantly more than the 38 transfers from the high oxygen concentration group.…”

“…All of them were prospective, but the randomization methods they used for examining the differences between the two oxygen concentrations from fertilization to ongoing pregnancies and live births are problematic. Randomization was either based on day of admission to the IVF laboratory [1], age of the woman, infertility factor, amount of gonadotrophins, number of retrieved oocytes [17], or per patient [15,19,27]. They all saw higher implantation, pregnancy and birth rates with reduced O 2 concentrations.…”

“…A better blastocyst outcome and a significant improvement in pregnancy and birth rates were found with low oxygen concentrations by Waldenström et al [27], but their study was not conducted on sibling oocytes. Kea et al [15] found that different oxygen concentrations did not significantly Capsule Implantation, pregnancy and live birth rate are higher, and more good quality embryos are available for transfer and freezing with reduced rather than with atmospheric oxygen concentrations during embryo incubation. affect fertilization rate, blastocyst formation and quality or pregnancy rate, but that there was a significant difference in the mean embryo score on day 3, in favor of the reduced oxygen concentration.…”

Diploid, but not haploid, human embryonic stem cells can be derived from microsurgically repaired tripronuclear human zygotes

“…21 Therefore, some studies suggested that the viability of pre-implantation embryos and the quality of blastocysts were all improved significantly when the embryos were cultured under conditions of low oxygen concentration. 22,23 More importantly, Lengner et al demonstrated that the human blastocysts contained pre-X-inactivation cells, and that this state was preserved in vitro through culture under 5% oxygen, which suggested that not only blastocyst formation but also ES cell derivation from these blastocysts was improved under hypoxic conditions. 24 Therefore, the hypoxic conditions would contribute to the improvement of the developmental competence of embryos and should be tested in the culture process of r1PN embryos in further study.…”