Received December 07, 2025
Accepted December 07, 2025

Objective: Single embryo culture has been adapted to select viable human embryos for transfer, with various efforts have been made to complement the drawbacks of individual culture. This study was aimed to evaluate the effects of different culture volumes on embryonic developmental competence. Methods: This retrospective cohort study included 6173 individually cultured sibling embryos obtained from 859 normal-responder women who underwent in vitro fertilization (IVF) or intracytoplasmic sperm injection between November 2018 and November 2019 at a single fertility center. The embryos were cultured in 30 (n=3271) or 10 μl (n=2902) of Sydney IVF cleavage medium under paraffin oil at 37 ˚C, 6% CO2, 5% O2 and 99% humidity. On day 3, the embryos were transferred to Sydney IVF blastocyst medium and the embryo quality (days 2, 3, and 5) and utilization rate (day 5) were evaluated. Results: No statistically significant differences were observed in embryo utilization rate (35.46 vs 35.25%; p=0.86) between embryos cultured in large or small drops of culture medium. Furthermore, no significant differences were observed in embryo quality on (day 2, 43.36 vs. 42.66%, p=0.18; day 3, 44.88 vs. 43.31%, p=0.22; day 5, 18.00 vs. 18.00%, p=0.82) and clinical pregnancy rates (days 3, 4, and 5) between the embryos cultured in two different culture volumes (37.91 vs. 40.63%; p=0.67). Conclusions: Culture volumes did not affect the embryo quality, embryo utilization rate, or clinical pregnancy rates. Our findings may provide baseline data supporting flexible culture medium volume adjustments for single-embryo cultures in laboratory practices.