There was no specific funding for the preparation of these proposed guidelines. Meetings were held opportunistically during scientific conferences and using online communication tools. H.N.C. is a scientific consultant for ESCO, supplier of Miri TL. I.E.A. is a minor shareholder in Unisense Fertilitech, supplier of the EmbryoScope. Full disclosures of all participants are presented herein. The remaining authors have no conflict of interest.

Objective To compare the dynamics of early development between embryos cultured in single and sequential media. Design Randomized, comparative study. Setting Private IVF centre. Patients A total of 446 metaphase II oocytes from 51 couples who underwent oocyte retrieval procedure for intracytoplasmic sperm injection. Forty-nine resulted in embryo transfer. Intervention Oocytes were split between single and sequential media produced by the same manufacturer and cultured in a time-lapse incubator. Main outcome measures Morphokinetic parameters until the embryos reached the 5-cell stage (t5), utilization, clinical pregnancy and implantation rates. Results Embryos cultured in single media were advanced from the first mitosis cycle and reached 2-to 5-cell stages earlier. There was not any difference between the durations for cell cycle two (cc20t3-t2) and s2 (t4-t3). The utilization, clinical pregnancy and implantation rates did not differ between groups. The proportion of cryopreserved day6 embryos to two pronuclei oocytes was significantly higher in sequential than in single media. Conclusions Morphokinetics of embryo development vary between single and sequential culture media at least until the 5-cell stage. The overall clinical and embryological parameters remain similar regardless of the culture system.

The aim of the present study was to examine the effect of culture under 5 and 20% oxygen on the development, differentiation and viability of zygotes and in-vivo-produced embryos at the 2-cell and 8-cell stages of development. First, zygotes collected in a common pool were cultured in 20% O2 for 0, 23, 46 and 95 h. Zygotes and in-vivo-produced embryos at the 2-cell and 8-cell stages of development were then cultured in 5 or 20% O2. The proportion of embryos reaching the compaction and blastocyst stages of development did not differ between groups regardless of the period of time embryos were cultured in 20% O2 or the stage at beginning of culture. Duration of culture under 20% O2 had a significant effect on total number of blastocyst cells. A stage-specific effect was observed on total and trophectoderm cell numbers in blastocysts resulting from the culture of zygotes and in-vivo-produced embryos under 20% O2. ICM and percent ICM development was significantly decreased by culture in 20% O2 at all stages examined. Oxygen concentration had no effect on implantation rate and fetal weights upon embryo transfer. However, transfer of zygotes grown to the blastocyst stage in 20% O2 resulted in a dramatic decrease in fetal development per blastocyst and fetal development per implantation. These results demonstrate that culture of F1 mouse zygotes in 20% O2 compromises the developmental potential of resultant blastocysts, which appear to be normal on morphological assessment.

No abstract

A machine learning-based decision support system would be useful in improving the success rates of IVF treatment.