Cryostorage tank failures: temperature and volume loss over time after induced failure by removal of insulative vacuum

Sustainability in the IVF laboratory: recommendations of an expert panel

The healthcare industry is a major contributor to greenhouse gas emissions. Assisted reproductive technology is part of the larger healthcare sector, with its own heavy carbon footprint. The social, economic and environmental costs of this collective carbon footprint are becoming clearer, as is the impact on human reproductive health. Alpha Scientists in Reproductive Medicine and the International IVF Initiative collaborated to seek and formulate practical recommendations for sustainability in IVF laboratories. An international panel of experts, enthusiasts and professionals in reproductive medicine, environmental science, architecture, biorepository and law convened to discuss the topics of importance to sustainability. Recommendations were issued on how to build a culture of sustainability in the workplace, implement green design and building, use life cycle analysis to determine the environmental impact, manage cryostorage more sustainably, and understand and manage laboratory waste with prevention as a primary goal. The panel explored whether the industry supporting IVF is sustainable. An example is provided to illustrate the application of green principles to an IVF laboratory through a certification programme. The UK legislative landscape surrounding sustainability is also discussed and a few recommendations on 'Green Conferencing' are offered.

Effect of exposed-to-air frequency of cryopreserved embryo on clinical outcomes of vitrified-warmed embryo transfer cycles: a retrospective analysis of 9,200 vitrified-warmed transfer cycles

BACKGROUND

Cryopreservation of embryos plays a major role in the in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. However, the storage condition of the cryopreserved embryo can change temporarily due to repeated retrieval of the embryo from the liquid nitrogen (LN2) tank during the practical application during cryopreservation. Whether the implantation potential of a cryopreserved embryo will be damaged when the cane containing it is temporarily exposed to air due to the transfer between the LN2 tank and LN2 container is yet to be elucidated. Also, whether the exposed-to-air frequency (EAF) of cryopreserved embryos influences the clinical outcomes is unclear.

OBJECTIVE

To investigate whether the EAF of cryopreserved embryo affects the clinical outcomes of vitrified-warmed embryo transfer.

METHODS

A total of 9200 vitrified-warmed embryo transfer cycles were included in this study. All cycles were divided into five groups according to different EAFs (2, 4, 6, 8, or ≥ 10). Post-warming survival rates and clinical outcomes, including implantation, clinical pregnancy and live birth rates were investigated. Kruskal-Wallis test and Pearson's chi-squared tests were used to compare the patient characteristics and clinical outcomes among the five groups. Furthermore, multivariate logistic regression analyses were conducted to investigate the association between EAF and clinical outcomes.

RESULTS

No significant differences were observed in the positive HCG rate, implantation rate and live birth rate (P > 0.05) among five EAF groups with respect to D3 embryo, D5 blastocyst and D6 blastocyst. Post-warmed survival rate of D3 embryos (P = 0.015) differed significantly among the five EAF groups, but it was not EAF-dependent. Although clinical pregnancy was different among the five groups with respect to D5 blastocyst (P = 0.042), multivariate logistic regression analysis adjusted for confounding variables suggested that EAF did not adversely affect clinical pregnancy or live birth.

CONCLUSION

These findings indicated that human vitrified embryos in the open system could be repeatedly retrieved from the LN2 tank without affecting the implantation potential of the embryo.

Damages and stress responses in sperm cells and other germplasms during dehydration and storage at nonfreezing temperatures for fertility preservation

Long-term preservation of sperm, oocytes, and gonadal tissues at ambient temperatures has the potential to lower the costs and simplify biobanking in human reproductive medicine, as well as for the management of animal populations. Over the past decades, different dehydration protocols and long-term storage solutions at nonfreezing temperatures have been explored, mainly for mammalian sperm cells. Oocytes and gonadal tissues are more challenging to dehydrate so little to no progress have been made. Currently, the detrimental effects of the drying process itself are better characterized than the impact of long-term storage at nonfreezing temperatures. While structural and functional properties of germ cells can be preserved after dehydration, a long list of damages and stresses in nuclei, organelles, and cytoplasmic membranes have been reported and sometimes mitigated. Characterizing those damages and better understanding the response of germ cells and tissues to the stress of dehydration is fundamental. It will contribute to the development of optimal protocols while proving the safety of alternative storage options for fertility preservation. The objective of this review is to (1) document the types of damages and stress responses, as well as their mitigation in cells dried with different techniques, and (2) propose new research directions.