Clinical outcome after culturing human preimplantation embryos in incubators with individual chambers compared to standard incubators: randomised trial.

Ronny Janssens, Romy Souffreau, Patrick Haentjens, Hilde Van De Velde, Greta Verheyen

Research output: Contribution to journalConference paper


Introduction: In IVF, the use of standard incubators with a single large incubation
chamber is generalised since the 80's. These type of incubators has been
criticised since each door opening results in fluctuations in temperature and gas
composition. In the 90's, smaller desktop incubators with individual culture
chambers flushed with premixed gas were developed. We aimed to validate a
new desktop incubator with 10 individual incubation chambers (G-185, K-Systems)
with gas regulation for CO2 and O2, for its performance in maintaining
stable culture conditions and for the clinical outcome. In a preliminary study on
sibling oocytes, better embryo quality was observed in the G-185 incubator. In
the present prospective randomised trial, culture for IVF/ICSI in a standard incubator
(SI) and in the G-185 incubator were compared with pregnancy rate as
primary endpoint.
Material and Methods: From June to December 2010, oocytes of 312 patients
were randomised for culture either in standard incubators (SI, HeraCell
240 or Thermoforma) or in the G-185. Cycles with at least 6 cumulus-oocyte
complexes and ejaculated (fresh and frozen) semen were included. PGD cycles
were excluded. Culture conditions (37.0°C - 6.0% CO2 - 5% O2, microdrop
culture without humidified atmosphere) and culture media (Sage) were identical
in both groups.
Results: In total, 278 cycles fulfilled the inclusion criteria and were included
for analysis, 138 in S Iand 140 in G-185. The age (34.4 ± 5.2 in SI vs. 33.1 ± 4.7
in G-185), number of oocytes collected (10.9 ± 4.3 vs. 11.6 ± 4.7), oocyte maturity
and fertilisation rate (75.4 vs. 75.0%) were similar in both groups. In two
SI and three G-185 cycles the transfer was cancelled because of OHSS risk,
and in two cycles in each incubator group the transfer was cancelled based
on insufficient embryo quality. Finally, 134 cycles cultured in SI resulted in a
transfer versus 135 cultured in G-185. In the G-185 group, more transfers were
performed on day 5 (40.7% vs 29.1%, P = 0.045). The point estimates for pregnancy rate (positive hCG) were more than 10 percent higher in the G-185 group compared with the SI group, although this increment was not statistically significant. Pregnancy rates per started cycle were 50.4% (69/137) and 39.0% (53/136) for G-185 and SI with a betweengroup difference + 11.4% (95% CI, - 0.3% to + 23.1%; p = 0.0583) in favour of G185. Likewise, the pregnancy rates per embryo transfer were 51.1% (69/135)
and 39.6% (53/134) for G185 and SI with a between-group difference + 11.6% (95% CI, - 0.3% to + 23.4%; p = 0.0569) in favour of G-185. The implantation rate (sacs with foetal heart beat) per embryo transferred was significantly higher in the G185 group (27.1% vs 18.5%), with a betweengroup
difference of + 8.5% (95% CI, + 0.4% to + 16.6%; P = 0.036) in favour of G185. However, a positive effect of a higher proportion of day 5 transfers cannot be excluded.
Conclusions: Among patients treated for IVF/ICSI, culture in the G185 incubator
with small individual chambers resulted in a trend towards higher pregnancy
rates. Since all culture variables were identical, we speculate that better
temperature and gas stability may explain these findings.
Original languageEnglish
Pages (from-to)40
Number of pages1
JournalHuman Reproduction
Publication statusPublished - Jul 2011
EventUnknown -
Duration: 1 Jul 2011 → …


  • incubators


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