Evaluation the effect of lowered incubator oxygen tension on embryo quality

Madaschi, Camila; Guilherme, Patrı́cia; Izzo, C.P.M.; Yamakami, Lucas; Fassolas, G.; Izzo, Carlos Roberto

doi:10.1016/j.fertnstert.2010.07.956

Cited by 2 publications

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“…Similar positive results excluded from this meta-analysis (e.g., data reported by only one study or data presented in a way making calcualtions impossible) have been reported by some RCTs (increases in biochemical [ 37 , 39 ] and cumulative [ 38 ] pregnancy rates and higher rates of live births [ 24 ]). In addition, other non-randomised studies have also reported increased implantation [ 21 ] and pregnancy [ 21 , 48 , 49 ] rates. On the basis of these data, it may seem attractive to consider low O 2 tension as a means to improve clinical outcomes.…”

Section: Discussionmentioning

confidence: 99%

IVF/ICSI outcomes after culture of human embryos at low oxygen tension: a meta-analysis

Sobrinho

Oliveira

Petersen

et al. 2011

Reprod Biol Endocrinol

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BackgroundImproved pregnancy, implantation, and birth rates have been reported after the use of reduced O2 concentration during embryo culture, mainly due to a reduction of the cumulative detrimental effects of reactive oxygen species. However, some studies have failed to report any positive effects. The objective of this meta-analysis was to evaluate the effect of a low-O2 environment on IVF/intracytoplasmic sperm injection (ICSI) outcomes.MethodsAll available published and ongoing randomised trials that compared the effects of low (~5%; OC~5) and atmospheric (~20%; OC~20) oxygen concentrations on IVF/ICSI outcomes were included. Search strategies included online surveys of databases from 1980 to 2011. The outcomes measured were fertilisation rate, implantation rate and ongoing pregnancy rates. The fixed effects model was used to calculate the odds ratio.ResultsSeven studies were included in this analysis. The pooled fertilisation rate did not differ significantly (P = 0.54) between the group of oocytes cultured at low O2 tension and the group at atmospheric O2 tension. Concerning all cycles, the implantation (P = 0.06) and ongoing pregnancy (P = 0.051) rates were not significantly different between the group receiving transferred sets containing only OC~5 embryos and the group receiving transferred sets with only OC~20 embryos. In a meta-analysis performed for only those trials in which embryos were transferred on day 2/3, implantation (P = 0.63) and ongoing pregnancy (P = 0.19) rates were not significantly different between the groups. In contrast, when a meta-analysis was performed using only trials in which embryos were transferred on days 5 and 6 (at the blastocyst stage), the group with transferred sets of only OC~5 embryos showed a statistically significantly higher implantation rate (P = 0.006) than the group receiving transferred sets with only OC~20 embryos, although the ongoing pregnancy (P = 0.19) rates were not significantly different between the groups.ConclusionsDespite some promising results, it seems too early to conclude that low O2 culture has an effect on IVF outcome. Additional randomised controlled trials are necessary before evidence-based recommendations can be provided. It should be emphasised that the present meta-analysis does not provide any evidence that low oxygen concentration is unnecessary.

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