A prospective, randomized trial on the effect of atmospheric versus reduced oxygen concentration on the outcome of intracytoplasmic sperm injection cycles.
OBJECTIVE
To assess whether the embryo cultivation at different oxygen tensions had any effect on intracytoplasmic sperm injection (ICSI) outcome.


METHODS
Prospective randomized trial.


METHODS
University clinical center.


METHODS
Women undergoing ICSI (n = 647).


METHODS
Culturing of embryos, either at 6% CO(2), 5% O(2), 89% N(2), or at 6% CO(2) in air.


METHODS
The primary outcome was ongoing pregnancy rates (PR).


RESULTS
cumulative PRs, implantation, and embryo quality, for both treatment groups and clinical outcomes for subgroups (optimal cycles, poor responders, older women).


RESULTS
Although low oxygen resulted in a higher proportion of good day 2 embryos (0.547 +/- 0.021 vs. 0.39 +/- 0.019) and optimal blastocysts (0.162 +/- 0.199 vs. 0.083 +/- 0.128), the ongoing PRs (31.6% vs. 27.1%) and implantation rates (28.8% vs. 25.2%) were similar in both oxygen groups. Low oxygen caused a higher cumulative PR (38% vs. 28.3%) in the main group and a higher PR in the poor responder subgroup (23% vs. 9.8%) with embryo transfers performed mostly on day 3.


CONCLUSIONS
The use of reduced oxygen in IVF is reasonable, irrespective of the duration of embryo culture. It improves embryo development and cumulative PR and is also recommended in poor responding cycles.
Kovacic
Borut
B
Department of Reproductive Medicine and Gynecologic Endocrinology, University Clinical Centre Maribor, Maribor, Slovenia. borut.kov@ukc-mb.si
Sajko
Mojca Cizek
MC
Vlaisavljević
Veljko
V
D000388:Air; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D002245:Carbon Dioxide / Q000494:pharmacology*; D046149:Embryo Culture Techniques / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D007246:Infertility / Q000628:therapy*; D008297:Male; D010062:Ovulation Induction; D010100:Oxygen / Q000494:pharmacology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*
D002245:Carbon Dioxide; D010100:Oxygen