OBJECTIVE: The suggested beneficial effects of coculture include the secretion of embryotrophic factors and the elimination of potentially harmful substances, thereby detoxifying the culture medium. Multiple feeder cells have been recommended, such as human endometrium, granulosa cell, fibroblast, cumulus cell, and even non-human cells or cell lines. However, some of the coculture techniques are difficult to perform, time-consuming, or with risk of infection. In this study, we used autologous cumulus cell as the feeder to perform coculture in poor prognostic patients and evaluated whether this coculture system improves day3 embryo development within the same patient.DESIGN: Observational study.MATERIALS AND METHODS: In our center, coculture was performed in patients who had failed multiple cycles with low cleavage rates or high fragmentation. A total of 175 cycles of autologous cumulus cell coculture were evaluated and only the patients, who had two consecutive cycles, one with regular culture and one with coculture, were included in the study. In both cycles the same type of culture media was used, except in the second cycle, a monolayer of autologous cumulus cells were plated in the dish. Day 3 embryo morphology was compared within each patient. Cleavage was the cell number assessed at 48 hours after coculture. Fragmentation was scored by 1 to 5 with 1 as the best. Paired t-test was performed using STATA 7.0.Table 1Comparison day 3 embryo morphology with coculture vs. regular cultureRegular CultureWith Autologousp#Embryo485546Average Cell#5.73 ± 1.626.43 ± 1.320.004Average Fragmentation score3.01 ± 0.913.13 ± 0.780.13 Open table in a new tab CONCLUSIONS: Our study suggests a cumulus cell coculture system may improve human embryo cleavage, but not fragmentation score. This result is consistent with our earlier data utilizing BRL cells. The mechanism of coculture needs to be further studied to explain this phenomenon. From a practical standpoint, autologous cumulus cell coculture is easy to perform, less time consuming and negligible risk for infection, and therefore, a feasible alternative to optimize human embryo culture system. OBJECTIVE: The suggested beneficial effects of coculture include the secretion of embryotrophic factors and the elimination of potentially harmful substances, thereby detoxifying the culture medium. Multiple feeder cells have been recommended, such as human endometrium, granulosa cell, fibroblast, cumulus cell, and even non-human cells or cell lines. However, some of the coculture techniques are difficult to perform, time-consuming, or with risk of infection. In this study, we used autologous cumulus cell as the feeder to perform coculture in poor prognostic patients and evaluated whether this coculture system improves day3 embryo development within the same patient. DESIGN: Observational study. MATERIALS AND METHODS: In our center, coculture was performed in patients who had failed multiple cycles with low cleavage rates or high fragmentation. A total of 175 cycles of autologous cumulus cell coculture were evaluated and only the patients, who had two consecutive cycles, one with regular culture and one with coculture, were included in the study. In both cycles the same type of culture media was used, except in the second cycle, a monolayer of autologous cumulus cells were plated in the dish. Day 3 embryo morphology was compared within each patient. Cleavage was the cell number assessed at 48 hours after coculture. Fragmentation was scored by 1 to 5 with 1 as the best. Paired t-test was performed using STATA 7.0. CONCLUSIONS: Our study suggests a cumulus cell coculture system may improve human embryo cleavage, but not fragmentation score. This result is consistent with our earlier data utilizing BRL cells. The mechanism of coculture needs to be further studied to explain this phenomenon. From a practical standpoint, autologous cumulus cell coculture is easy to perform, less time consuming and negligible risk for infection, and therefore, a feasible alternative to optimize human embryo culture system.