Safety and efficacy of the automated liquid-phase embryo storage, Hatchferti: a pilot study

To date, no fully automated liquid-phase embryo tank has been implemented in assisted reproductive technology (ART) laboratory and its impact on the safety and efficacy of embryo storage remains unknown. To evaluate its performance, the Hatchferti group (HG) stored a total of 230 clinically discarded 3PN zygotes (n = 143) and day 3 cleavage embryos (n = 87) from September 2023 to April 2024. These embryos were vitrified and stored for 30, 90, and 180 days, their survival and culture results were statistically analyzed. The total 3PN zygote cleavage rate after thawing was compared with the fresh 2PN zygote cleavage rate of 2023 laboratory annual data (n = 32,520). A 7-day period of workload data showed that the operating time in conventional liquid nitrogen tank group (CG) required for storage and retrieval were 6.71 ± 1.28 and 39.00 ± 13.42 minutes, respectively, while that in HG were significantly lower (1.95 ± 0.04 and 0.96 ± 0.03 minutes respectively, P < 0.05). In order to assess the stability of the operating temperature, during the 6-month study period, the temperature readings in the retrieval area were -177.84 ± 1.53 °C, and the storage area temperatures were -195.47 ± 2.01 °C and -195.81 ± 0.94 °C meeting the expected temperature for embryo storage. In the comparison between different freezing time groups, there was no statistically significant difference in the recovery rates of 3PN embryos and day 3 cleavage embryos between groups (both 100%, P > 0.05). There was no statistically significant difference in the cleavage rate of 3PN embryos after thawing between groups (95.56%, 95.83%, 100%, P > 0.05, respectively). There was no significant difference in the total zygote cleavage rate after thawing between HG (for the entire experimental period) and 2023 laboratory annual data (97.2%, 97.76%, P > 0.05). In conclusion, Hatchferti has demonstrated its safety and efficacy, showing promising potential for application in the ART laboratory.