Extended embryo culture: use of two media simultaneously is an optimal approach to maximize blastocyst formation and utilization

Abstract

Objective: The evaluation of a commercially prepared embryo culture medium (CCM-20, Vitrolife) and an in house prepared culture medium (SGB) for the development of human embryos to the blastocyst stage, up to day 7 in vitro. Design: This was a retrospective study at a private IVF clinic. Patients for this study were treated from August, 2000 to December, 2001. Patients were chosen for extended culture to day 5, 6 or 7 based on number of embryos, quality of embryos on day 3 of culture, age of patient, diagnosis and embryo development and quality in previous cycles. Materials/Methods: Once patient selection was made, embryos were equally divided and cultured in each medium preparation. In the case of an odd number of embryos, CCM-20 was the default medium. Culture dishes (NUNC, 35mm) were prepared by scratching the patients name and media type on the bottom of the dish. Five mls of oil (Sage, BioPharma) were pipetted into each dish. Ten microliter droplets were pipetted into the center of the dish. Droplets for rinsing the embryos were placed around the dish perimeter. Dishes were pre-equilibrated in the incubator for four hours before the embryos were moved into the extended culture media. This change over occurred on day 3 and day 5 of embryo culture. Each embryo was rinsed several times before being placed into one of the center droplets. All embryos were numbered and a daily record of the development of each embryo was kept as part of the patient cycle data. Embryos were chosen for ET and cryopreservation on day 5, 6 or 7 based on inner cell mass, trophectodermal development and degree of expansion. All embryos for ET on day 6 or 7 underwent assisted hatching. Results: Table I data were broken into the three separate series of the study period. This was done to monitor any change in the performance of the SGB medium. For all data points, where the series were separated and where they were combined, it appears that the CCM-20 media had a slight advantage over the SGB media. This might be explained in part, by the fact that the total number of embryos differed in the groups. (2935 CCM-20, 2822 SGB) Pregnancy rate and implantation rate for CCM-20 and SGB were 54.2, 41.3 and 58.8, 52.9, respectively. It appeared that the SGB performed marginally more successfully than the CCM-20 for PR and IR.Table ISeries% Embryos of Blast% Embryos to ET% Embryos to Cryo% Total UtilizationCCM-20SGBCCM-20SGBCCM-20SGBCCM-20SGB2453.343.417.212.520.017.137.229.62555.442.216.912.320.715.937.628.22654.448.614.814.121.117.735.931.824, 25, 2654.445.016.113.020.716.936.830.0 Open table in a new tab Conclusions: Both media performed well for the development of blastocysts for both ET and cryopreservation. Pregnancy rates and implantation rates were also comparable. A significant advantage of an in house prepared medium is less time is lost in its use due to a minimizing of testing and shipping time when compared to a commercial medium. Additionally, routine splitting of embryos on day 3 into two extended culture media allows the potential to default to one or other of the media if a pronounced drop in embryo quality is perceived due to suboptimal quality of either medium. Supported by: NA.