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

Abstract 

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 30μl 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.

In contrast to animal data group culture does not increase preimplantation development in humans. This prospective study was done to test a new type of culture dish allowing for individual culture and any possible effect of autotrophic factors. Within a 6-month period, 72 patients with nine or more fertilized eggs were enrolled in this prospective evaluation. The 936 zygotes were split into three subgroups (individual culture, individual culture with contact to neighbours, group culture). All concepti were cultured in 30μl 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 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 and blastulation as compared with individual culture. A better blastocyst quality was observed in group culture. As a trend, more life births were achieved when blastocysts derived from group culture were transferred. This is first evidence that grouping embryos improves preimplantation development in human. Based on these results, it is recommended that culture volume should be reduced or embryo density increased.

Keywords: autotrophic factors, blastocyst formation, culture volume, embryo density, group culture