Is a review of standard procedures for cryopreservation needed?
Safe and effective cryopreservation —should sperm banks and fertility centres move toward storage in nitrogen vapour?
Mathew Tomlinson1 and Denny Sakkas
Assisted Conception Unit, Birmingham Women's Hospital, Edgbaston, Birmingham B15 2TG, UK
A recent consultation documentation by the Human Fertilisation and Embryology Authority (HFEA) which focused on the safe cryopreservation of gametes and embryos highlighted the need for a review of the way that fertility clinics in the UK store potentially infective material. The main points for consideration were to: (i) ensure containers used for cryopreservation are guaranteed by manufacturers to withstand low temperatures; (ii) use secondary containers, i.e. `double bagging' of samples if stored in the liquid phase; and (iii) store in nitrogen vapour as a `safer' alternative. In this article we examine a number of issues related to vapour storage which need careful consideration, including safety, cost and the effectiveness of various storage techniques in maintaining gamete and embryo viability. We also discuss the effectiveness of vapour storage in comparison with current liquid nitrogen storage techniques. In conclusion, we propose that fertility clinics should be compelled to review their cryopreservation procedures, not just because of new legislation or indeed fear of litigation but by a moral obligation.
Key words: cryopreservation /nitrogen vapour/safety/sperm banks
Source: Human Reproduction, Vol. 15, No. 12, 2460-2463, December 2000.