These data suggest that a combined evaluation of the Z-score and day 3 embryo morphology is highly predictive of embryo outcome after IVF/ICSI. The Z-score could be of great help in the selection of embryos for cultures extended to later stages. The Z-score alone, or preferably in combination with day 3 embryo morphology, is useful in the determination of the most suitable embryos and the number of embryos for transfer, thus achieving the optimal chance of conception while reducing the risk of high order multiple pregnancy.

These phenomena suggest that oocyte maturity produced in vivo determine the fertilization potential and subsequent blastocyst quality in vitro.

PurposeReactive oxygen species (ROS) are thought to play a critical role in the success of IVF. The relationships between oxidative stress parameters in culture media and IVF outcomes have not been extensively investigated. The objective of this study is to examine the relationships between early human embryonic parameters and levels of ROS in culture media.MethodsThis prospective study was conducted with 2633 spent culture media collected from patients undergoing conventional IVF (n = 101) and intracytoplasmic sperm injection (ICSI) (n = 60). Both fertilization and early culture were performed in universal IVF medium and G series medium. ROS levels were measured by chemiluminescence assays using luminol as the probe on days 1, 3, and 5 and determined the relationships of ROS levels with zygote condition, embryo quality, and clinical pregnancy rate.ResultsROS levels per embryo in culture media on the corresponding days 1, 3, and 5 showed significant correlations between each pair in the total cohort. Similar results were observed in the IVF and ICSI groups, but day 1 and day 3 ROS levels were significantly higher in culture media of IVF than of ICSI embryos. ROS levels in culture medium were not significantly associated with embryo quality, blastocyst formation, or arrest. ROS levels on day 1 were similar in media of normally fertilized zygotes, unfertilized oocytes, and polyspermic zygotes and were not associated with delayed embryonic development, high fragmentation, blastocyst formation, or arrest after prolonged culture. ROS levels in media were not associated with the likelihood of conception.ConclusionsROS levels in culture media may not be an effective indicator of embryo selection for IVF.

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