Adenosine Triphosphate Content in Human Unfertilized Oocytes, Undivided Zygotes and Embryos Unsuitable for Transfer or Cryopreservation

OBJECTIVE: To investigate the relationship between adenosine triphosphate (ATP) content and developmental potential in human oocytes, zygotes and embryos. METHODS: ATP content was determined using a bioluminescence assay in 72 unfertilized oocytes, 26 undivided zygotes and 70 embryos unsuitable for transfer or cryopreservation, obtained from 52 women undergoing in vitro fertilization and embryo transfer (IVF-ET). RESULTS: The mean ATP content increased with development: zygotes had a significantly higher ATP content than oocytes, and embryos had a significantly higher ATP content than both zygotes and oocytes. Within the embryo group, the ATP content was significantly higher in polypronuclear embryos than in inferior embryos with substantial fragmentation. When analysed in relation to IVF-ET outcome, the ATP content of oocytes and embryos from women who became pregnant was significantly higher than in oocytes and embryos from those who did not become pregnant. CONCLUSIONS: Reduced ATP content may be related to fertilization failure, arrested division and abnormal embryonic development. The differences observed in oocyte and embryo ATP content between women who became pregnant and those who did not suggests that mitochondrial function is correlated with individual fertility.