Group culture of human zygotes is superior to individual culture in terms of blastulation, implantation and life birth.

This prospective study tested a new type of culture dish for the effects of individual culture and autotrophic factors. Within a 6-month period, 72 patients with nine or more fertilized eggs were enrolled in this prospective evaluation. Their 936 zygotes were split into three subgroups (individual culture, individual culture with contact to neighbours, group culture). All concepti were cultured in 30 μl drops (medium change on day 3) until blastocyst stage. On day 5, a single-blastocyst transfer was performed and the remaining blastocysts of good quality were vitrified. Fertilization rates were 69% for IVF and 81% for intracytoplasmic sperm injection. Blastulation was 48%. Single-blastocyst transfer resulted in a clinical pregnancy rate of 54%. Group culture was superior in terms of compaction (P<0.01) and blastulation (P<0.001) as compared with individual culture. A better blastocyst quality was observed in group culture (P<0.05). As a trend, more life births were achieved with blastocysts derived from group culture. As far as is known, this is the first evidence that grouping embryos improves preimplantation development in human and it is recommended that culture volume should be reduced or embryo density increased.