Time-dependent O2 consumption patterns determined optimal time ranges for selecting viable human embryos.

OBJECTIVE

To evaluate correlations between metabolic activity and implantation potential of transferred embryos in a study based on oxygen (O(2)) consumption (OC) measurements, because O(2) uptake is directly related to the capacity of an embryo to produce energy via adenosine triphosphate.

DESIGN

Retrospective cohort study.

SETTING

Infertility institute.

PATIENT(S): Five hundred seventy-five injected oocytes in 56 first oocyte donation cycles with embryo transfer on day 3.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): We analyzed embryo destination viability and implantation depending on the embryo OC rate obtained from 47,741 measurements (up to 85 measurements per embryo, 2-3 measurements per hour). OC patterns were analyzed in relation to the time elapsed from sperm microinjection, to the final destination of the embryos (transferred, frozen, or discarded), to ongoing pregnancy, and by successful implantation.

RESULT(S): OC was found to decrease during embryonic development. OC patterns from 52 hours onward showed the strongest correlation with implantation success. Regarding embryo destination, the same patterns were observed.

CONCLUSION(S): OC from individual embryos revealed significant differences, mainly close to the time of transfer, when OC pattern was associated with successful implantation. Therefore, measuring the OC pattern of human embryos culture up to 72 hours could be used to select the embryo with best developmental potential.