Quality control in the IVF laboratory: in-vitro and in-vivo development of mouse embryos is unaffected by the quality of water used in culture media.

We have examined the effect of media made with tap water or with various purified waters on the fertilization of mouse oocytes, their development to blastocysts, their rate of hatching in vitro and their survival after transfer to recipients. Zona-intact and zona-free embryos, as well as cell clusters from 8-cell stage embryos, were also used. The macromolecular composition of the media was varied. We were unable to find any adverse effect of tap water under any condition examined. The implications of these findings for quality control in IVF units are discussed.